Ladera, CA

Unincorporated San Mateo County has no dedicated gas-powered leaf blower ban or specific leaf-blower ordinance; the recent leaf-blower bans and electric-blower rebate programs are city-level (e.g., City of San Mateo, Atherton, Redwood City). In unincorporated areas, blowers are governed by the general Chapter 4.88 noise standards.

Amplified music in unincorporated San Mateo County is regulated by County Code Chapter 4.88: it must stay within the exterior dBA limits of Section 4.88.330 and must not be unreasonably loud under the General Noise Regulation (4.88.350). There is no separate county amplified-sound permit chapter in the noise code itself.

Noise from motor vehicles operated on public roads in unincorporated San Mateo County is primarily controlled by the California Vehicle Code, which requires an adequate muffler and prohibits modified exhaust that amplifies noise. The County's Chapter 4.88 noise limits generally address stationary, on-property noise rather than vehicles in transit on public rights-of-way.

County Code 4.88.330 sets exterior noise limits at residences, schools, hospitals, churches and libraries on a sliding scale by how long the noise lasts in an hour. Daytime (7 a.m.-10 p.m.) limits run from 55 dBA (30 min/hr) up to 75 dBA (instantaneous max); nighttime (10 p.m.-7 a.m.) limits are 5 dBA lower, from 50 to 70 dBA.

Outdoor music in unincorporated San Mateo County must comply with the exterior decibel limits in County Code 4.88.330 and must not be unreasonably loud under 4.88.350. The County noise code has no special outdoor-music exemption, so evening and late-night events face the stricter 10 p.m.-7 a.m. nighttime limits.

Industrial and commercial noise in unincorporated San Mateo County is controlled through the exterior noise standards of County Code 4.88.330 (measured at nearby residences, schools, hospitals, churches and libraries) and the General Noise Regulation 4.88.350, with construction-noise exemptions limited to set hours under 4.88.360.

Aircraft noise is regulated by the FAA under federal law, not by the County's local noise ordinance. The County of San Mateo operates San Carlos and Half Moon Bay airports and runs a voluntary Airports Noise Abatement Program with voluntary flight procedures, a 'Fly Friendly' education effort and a noise-complaint hotline at (844) 266-6266.

There is no separate barking-dog decibel rule for unincorporated San Mateo County; persistent barking is addressed under the County's General Noise Regulation (4.88.350), which prohibits unreasonably loud, unnecessary or unusual noise that disturbs the peace, with animal complaints handled through the County and its contracted animal-control services.

In unincorporated San Mateo County, Noise Control Chapter 4.88 sets nighttime hours of 10:00 p.m. to 7:00 a.m. with stricter exterior dBA limits than the 7:00 a.m. to 10:00 p.m. daytime period, measured at residences, schools, hospitals, churches and libraries.

Under County Code 4.88.360, construction, demolition, repair, remodeling and grading in unincorporated San Mateo County is exempt from noise limits only between 7:00 a.m. and 6:00 p.m. on weekdays and 9:00 a.m. and 5:00 p.m. on Saturdays. No construction is allowed on Sundays, Thanksgiving or Christmas.

Registration is handled through a Short-Term Rental Permit application to the Planning and Building Department plus a Transient Occupancy Registration Certificate from the Tax Collector. Owners must designate a local contact, post performance standards, and meet fire-safety standards before a permit issues.

San Mateo County's Coastal Zone STR ordinance does not require the rental to be the owner's primary residence. Non-owner-occupied (whole-home) short-term rentals are allowed, subject to the permit, a 180-night cap, and all performance standards under Section 6401.3.

Owner presence is not required, but Section 6401.3(6)(c) requires a designated local contact person within a 20-mile radius, available at all times during occupancy, able to physically respond within one hour in emergencies. Owner-present nights are exempt from the 180-night cap.

Under Section 6401.3(2)(c), a Coastal Zone STR cannot be rented for more than 180 nights per calendar year. Any night the property owner is present at the address does not count against the 180-night limit.

Section 6401.3(6)(k) requires each Coastal Zone STR owner to maintain at least $500,000 in liability insurance on the short-term rental while it is occupied by short-term tenants. Proof of liability insurance must be submitted with the permit application.

Under Zoning Regulations Section 6401.3(6)(a), the maximum number of short-term tenants is two persons per bedroom rented plus two additional persons. Children under 12 are not counted. Renting one bedroom allows up to four tenants.

STR operators in unincorporated San Mateo County must collect and remit Transient Occupancy Tax of 10% of rent under Ordinance Code Chapter 5.136 (Section 5.136.020) and pay the Planning Department's STR permit fee. The County permit page lists an approximate permit fee of $500.

Section 6401.3(6)(b) requires each single-family STR to provide at least one on-site parking space (garage, driveway, or other on-site area), or at least two spaces if maximum occupancy exceeds eight tenants. Multifamily STR units need at least one on-site space.

In unincorporated San Mateo County, short-term rentals are only allowed in the Coastal Zone and require a Short-Term Rental Permit issued under Zoning Regulations Section 6401.3. STRs are permitted in legal R-1 and R-3 residences; accessory/second units are excluded.

Section 6401.3(6)(f) requires every Coastal Zone STR to comply with the County Noise Ordinance (Ordinance Code Chapter 4.88), post a copy of that chapter inside the unit, and avoid activities producing noise, dust, odor, or vibration detrimental to neighbors.

Properties in the Wildland-Urban Interface of unincorporated San Mateo County must maintain defensible space under California Public Resources Code 4291: 100 feet of clearance around structures. CAL FIRE / San Mateo County Fire conducts defensible space inspections, and roadside vegetation must be cleared to specified clearances.

Small recreational backyard fires are allowed in unincorporated San Mateo County under California Fire Code section 307.4 with required setbacks and constant attendance, but all backyard burning of yard waste or trash is prohibited and wood fires are banned on Spare the Air days under BAAQMD Regulation 6, Rule 3.

Smoke alarms in unincorporated San Mateo County dwellings are governed by California Health & Safety Code section 13113.7 and the California Fire/Building Codes. Newer battery-only alarms must have a 10-year sealed non-replaceable battery, and alarms must be replaced 10 years after the manufacture date. Violations are a $200 infraction.

Propane (LPG) storage in unincorporated San Mateo County follows the California Fire Code Chapter 61 and NFPA 58, enforced by CAL FIRE / San Mateo County Fire. Residential aggregate capacity is limited, tanks must meet setback and clearance rules, and permits are required above threshold quantities.

Unincorporated San Mateo County contains Moderate, High, and Very High Fire Hazard Severity Zones, with the Santa Cruz Mountains and coastal hills (La Honda, Pescadero, and similar) at the highest risk. Mapped zones trigger defensible space (PRC 4291), WUI building standards (CBC Chapter 7A), and real estate disclosure.

All fireworks are illegal in unincorporated San Mateo County under County Ordinance Code Chapter 5.28, including state-approved 'Safe and Sane' fireworks like sparklers, fountains, and snakes. Possession, sale, and use carry a $1,000 fine, raised from prior levels in May 2021.

All backyard burning is prohibited throughout San Mateo County. Open burning is regulated by the Bay Area Air Quality Management District and requires a CAL FIRE burn permit, and may only occur on declared permissive burn days. Most residential yard-waste burning is illegal; use green-waste collection instead.

Recreational fire pits in unincorporated San Mateo County follow California Fire Code section 307.4: recreational fires must stay at least 25 feet from structures and portable outdoor fireplaces at least 15 feet. Wood burning is also illegal anywhere in the Bay Area on any Spare the Air Alert day under BAAQMD Regulation 6, Rule 3.

Unincorporated San Mateo County has no blanket overnight on-street parking ban. The County Ordinance Code instead targets oversized vehicles and trailers on designated streets (Section 7.28.070) and limits commercial vehicles in residential zones to one hour (Section 7.28.030). Otherwise, the state 72-hour rule and any posted local time limits control overnight parking.

County Ordinance Code Section 7.28.070 ("No Oversized Vehicle Parking") lets the Board of Supervisors bar oversized vehicles over six feet high from designated residential streets and trailers of any size from designated public streets in the unincorporated area. Exceptions cover loading, public-utility service, up to eight hours for emergency repairs or a tow, emergency vehicles, and wheelchair-accessible vans.

For new construction in unincorporated San Mateo County, the County's local amendments to the California Building and Energy Codes require EV charging infrastructure. Adopted February 25, 2020 and effective for permits, the rules require commercial buildings (excluding office) to install Level 2 EV charging at 6% of parking spaces and Level 1 circuits at 5%. Residents apply for EV charger permits through County Planning and Building.

On unincorporated County streets, yellow curbs are freight loading zones for active loading and unloading only (not for parking commercial-plated vehicles), and white curbs are passenger loading zones. On private development sites, the Title 8 Development Code requires off-street loading spaces sized at least 10 feet by 25 feet with 15 feet of vertical clearance for uses that receive or distribute merchandise.

Curb markings on unincorporated County roads are installed by the Department of Public Works and only after Board of Supervisors approval. Standard California curb colors apply: red means no parking, green means time-limited parking, yellow and white are loading zones, and blue is disabled parking. The County charges $80 plus $10 per foot for paint and/or signs; residents may not paint County curbs themselves.

Under County Ordinance Code Chapter 7.60, it is unlawful and an infraction to abandon, park, store, or leave any abandoned, wrecked, dismantled, or inoperative vehicle on public or private property for more than ten days unless fully enclosed in a building. The County adopts this abatement authority under California Vehicle Code Section 22660, and Section 7.60.140 makes violation an infraction.

On unincorporated County roads, on-street parking is governed by the County Ordinance Code Title 7 (Vehicles and Traffic) and the California Vehicle Code. The County Department of Public Works installs curb-color and time-limit restrictions only after Board of Supervisors approval. Curb colors follow statewide meanings, and unposted streets default to the state 72-hour rule.

Under County Ordinance Code Section 7.28.030, it is unlawful to park a commercial vehicle for more than one hour on any street in a residential zone of unincorporated San Mateo County, except while actually transacting lawful business there or when temporarily disabled. On private commercial sites, the Title 8 Development Code bars commercial-vehicle storage in required front-yard setbacks.

The County Title 8 Zoning and Development Code limits where on-lot vehicles may be parked: no required parking space is allowed within a required front yard except in narrow circumstances, and on-site parking must connect to the street by access driveways. For accessory dwelling units, up to three spaces may be in the front or side yard, but no more than 600 sq. ft. of the front yard may be used for parking.

In unincorporated San Mateo County, oversized vehicles over six feet high and trailers of any size may be barred from designated residential and public streets under Ordinance Code Section 7.28.070. On residential lots, the Title 8 Development Code limits where vehicles may be parked, and a recreational vehicle may only serve as temporary living quarters during construction of a permanent home.

A building permit is required for a fence built on top of a retaining wall in unincorporated San Mateo County. Under the California Building Code, retaining walls over 4 feet high (measured from the bottom of the footing) — or any wall supporting a surcharge — also require a permit.

Fences in unincorporated San Mateo County must comply with Chapter 8.332 height limits, corner-lot sight-distance rules, and grade-based measurement. Pool fencing, right-of-way encroachment, and Coastal Zone parcels carry additional requirements.

San Mateo County's countywide fence ordinance (Ch. 8.332) regulates fence height and placement rather than materials, and expressly recognizes wood and cyclone fencing. Some specific districts and design-review overlays restrict materials like chain link, corrugated metal, and masonry near street frontages.

Wood and cyclone (chain-link) fences are the standard, permit-exempt materials in unincorporated San Mateo County when built within height limits. Masonry fences require a building permit, and certain districts restrict materials near street frontages.

Unincorporated San Mateo County enforces California Swimming Pool Safety Act (H&S Code §115920-115929) and CBC Chapter 31B. Minimum 60-inch barrier, self-closing/self-latching gates, plus at least TWO additional drowning prevention features for new pools since 2018.

San Mateo County's zoning code sets fence heights but does not allocate cost between neighbors. Boundary-fence cost sharing is governed by California Civil Code 841, which presumes adjoining owners are equally responsible and requires 30 days' written notice before incurring shared costs.

A wooden or cyclone fence that meets the county zoning height limits generally needs no building permit. A building permit is required for fences built above a retaining wall, for masonry walls, and for taller fences. A separate Fence Height Exception is needed to exceed standard limits.

In unincorporated San Mateo County, fences, walls, and hedges may not exceed 4 feet in any required front yard and 6 feet in side or rear yards. Corner-lot fences within the sight triangle are capped at 4 feet. Height is measured from the lowest adjacent natural grade.

Unincorporated San Mateo County allows backyard chickens and ducks on residential parcels of at least 2,500 square feet. Up to 6 birds are allowed on lots of 2,500 to 7,499 square feet and up to 10 on lots of 7,500 square feet or more. Roosters are prohibited, and birds must be kept in a rear-yard coop.

In unincorporated San Mateo County, a household keeping more dogs or cats needs a permit. An animal fanciers permit covers up to a total of ten dogs and/or cats, and a kennel or cattery permit is required to keep more than ten dogs, cats, or any combination per dwelling or business.

Keeping livestock in unincorporated San Mateo County depends on the parcel's zoning district. Animal control under Title 6 covers dogs, cats, exotic animals, and poultry, while livestock such as horses, cattle, sheep, and goats is governed by the County zoning/Development Code, which permits agricultural animals on appropriately zoned and sized rural and agricultural parcels.

Cats over three months old in unincorporated San Mateo County must be licensed and rabies-vaccinated. The County Ordinance Code also requires that unaltered cats over six months be either spayed/neutered or covered by an unaltered-animal license or breeding permit. There is no general cat-leash requirement.

The County Ordinance Code does not contain a specific prohibition on feeding wildlife in unincorporated San Mateo County. County agencies strongly advise against feeding deer, coyotes, raccoons, and other wild animals because it draws predators and creates nuisances. Intentionally interfering with certain wildlife is also restricted by California state law.

Unincorporated San Mateo County has no separate 'hoarding' ordinance, but its permit tiers cap how many animals a household may keep and its animal-care standard prohibits neglect. Keeping animals without proper food, water, shelter, or care violates the County Code, and severe neglect is a crime under California Penal Code Section 597.

Unincorporated San Mateo County prohibits keeping any exotic animal without a use permit from the Planning and Building Department. The County Ordinance Code defines exotic animals broadly to include big cats, wolves and other wild canids, primates, elephants, and any species venomous to humans. California state law separately restricts many wild species.

Unincorporated San Mateo County has no breed-specific ban. The County Ordinance Code regulates individual dogs as dangerous or vicious based on behavior, not breed. California state law (Food & Agricultural Code) also bars breed-discriminatory licensing or ownership bans, though breed-specific spay/neuter programs are permitted.

Beekeeping is broadly allowed in unincorporated San Mateo County on a nuisance-avoidance basis. California state law requires every beekeeper to register hive locations with the County Agricultural Commissioner within 30 days of establishing the apiary, and apiaries away from a residence must be marked with owner contact information.

In unincorporated San Mateo County, dogs must be leashed and under control whenever they are on public property or any unenclosed premises. The County Ordinance Code has no voice-control exception, so dogs must be leashed at all times except in designated off-leash areas.

Unincorporated San Mateo County abates hazardous fire vegetation through its fire districts under California Health & Safety Code 14875 et seq. and Government Code 25845. Programs such as Coastside Fire's require mowing weeds and grass to no taller than 4 inches; lots of one acre or less are cleared entirely, and larger lots need a 30-foot perimeter fire break.

Residential rainwater harvesting is encouraged in unincorporated San Mateo County. Under California's Rainwater Capture Act, rooftop rain barrels and cisterns under 360 gallons for outdoor non-potable use need no state water permit. The Countywide Water Pollution Prevention Program offers rebates of $50-$150 per rain barrel, plus a possible $50 bonus in some areas.

Unincorporated San Mateo County encourages native and drought-tolerant landscaping rather than mandating it for homeowners. The Countywide Water Pollution Prevention Program promotes natives for pollinators and watershed health, and BAWSCA's Lawn Be Gone rebate pays up to $4 per square foot to replace lawn with low-water plants. WELO indirectly favors natives through plant-factor rules.

California's SB 1383 organics law requires unincorporated San Mateo County residents to keep food scraps, yard trimmings, and food-soiled paper out of the trash. Single-family homes get curbside organics (green cart) service and must sort organics into it. The County aims to cut organic-waste disposal 75% by 2025; non-compliance can lead to fines.

Unincorporated San Mateo County does not ban or specifically permit-regulate artificial turf on private property, and the County's WELO governs water budgets without mandating or prohibiting synthetic turf. A right-of-way permit is needed only if turf extends into the public parkway. California law (Civil Code 4735) bars HOAs from prohibiting water-efficient landscaping.

Unincorporated San Mateo County has no general residential lawn-height limit. Grass height is regulated only through wildfire defensible space: in State Responsibility Areas (CAL FIRE) and high fire hazard zones, annual grass must be mowed to a maximum height of 4 inches as part of the 100-foot clearance required by California Public Resources Code 4291.

Unincorporated San Mateo County enforces a Water Efficient Landscape Ordinance (WELO) implementing California's Model WELO. It applies to new landscapes of 500 sq ft or more and rehabilitated landscapes of 2,500 sq ft or more, capping turf, requiring low-water (WUCOLS 0.3) plants, 3 inches of mulch, and compost in the soil.

In unincorporated San Mateo County, pruning a Protected Tree generally does not need a permit, but a Protected Tree Pruning Permit is required to prune a Protected Indigenous Tree where the cut removes a branch or trunk 6 inches in diameter (19 inches circumference) or larger. Trees in the County right-of-way are trimmed by Public Works for safety only.

Unincorporated San Mateo County requires a Protected Tree Removal Permit before removing a protected tree. Any tree 12.1 inches in diameter (38 inches circumference) or larger is protected, and listed indigenous species (oaks, madrone, buckeye) are protected at lower diameters. Removal requires replacement planting per Table 2 of Ordinance 8.400.

Unincorporated San Mateo County does not require a separate home-occupation permit. A customary, incidental home occupation is allowed by right in residential zones as long as all the County's home-occupation conditions are met, so no special application or land-use approval is needed.

Cottage food operations in unincorporated San Mateo County are regulated under California's Homemade Food Act. San Mateo County Environmental Health registers Class A operations and permits/inspects Class B operations. Class A is capped at $75,000 and Class B at $150,000 in annual gross sales, and operators are limited to a set product list.

By California state law (Health & Safety Code 1597.40-1597.46, as amended by SB 234), small and large family day care homes are a residential use by right in unincorporated San Mateo County. No conditional use permit is required, and the County cannot impose a business license, fee, or tax to operate one. The home must be licensed by the State.

A home occupation in unincorporated San Mateo County may have only one sign or name plate, not exceeding 2 square feet, showing the name and occupation only. It must be attached flat to the dwelling and may not be illuminated, and no other display of the business may be visible from the street.

Customer visits to home businesses in unincorporated San Mateo County are restricted to incidental levels. Retail sales, regular appointments, and commercial deliveries creating traffic or parking impacts are prohibited.

Customary, incidental home occupations are allowed in unincorporated San Mateo County's residential zones (RE, RH, R-1, R-2, R-3, RM and PAD) with no separate permit if conditions are met: no non-resident employees, no retail business, no more than one-fourth of the ground-floor area used, and no exterior evidence of the business.

In unincorporated San Mateo County, carports are accessory structures regulated by Development Code Chapter 8.348, and required off-street parking may be provided in garages or carports under Chapter 8.344. On steep or elevated front lots, a carport or garage may be built to the front lot line.

Unincorporated San Mateo County has no separate tiny-home ordinance. A tiny home on a permanent foundation can qualify as an ADU under Development Code Chapter 8.392. California ADU law requires a permanent foundation, so movable tiny homes on wheels generally do not qualify as ADUs.

In unincorporated San Mateo County, ADUs are governed by Development Code Chapter 8.392 (non-coastal) and Chapter 8.396 (coastal). Ministerial approval, no minimum lot size, 4-foot side/rear setbacks, and no short-term rental. Junior ADUs under 500 sq ft require owner-occupancy.

Unincorporated San Mateo County permits converting a garage into an ADU under Development Code Chapter 8.392. California ADU law (Gov. Code 66314) bars the County from requiring replacement parking when a garage is converted to an ADU, and approval is ministerial within 60 days.

In unincorporated San Mateo County, a detached tool/storage shed needs no building permit if it is 120 sq ft or less and 12 feet or less in height. Detached accessory buildings are governed by Development Code Chapter 8.348, which sets a 3-foot minimum from property lines.

Spas and hot tubs in unincorporated San Mateo County require a County pool/spa building permit and are subject to California's Swimming Pool Safety Act. A spa equipped with an approved safety cover (ASTM F1346) can satisfy the barrier requirement that otherwise applies to pools.

In unincorporated San Mateo County, building a swimming pool or spa requires a building permit and a boundary survey from the Planning and Building Department. Applicants submit plot plans, structural/plumbing/electrical and mechanical details, engineering and energy calculations, and pay building, plan-check and related fees.

Above-ground pools in unincorporated San Mateo County are treated like other swimming pools: they require a County building permit and survey, and they must meet California's Swimming Pool Safety Act barrier and safety-feature requirements before use.

Unincorporated San Mateo County follows California's Swimming Pool Safety Act for pool barriers. A qualifying enclosure must be at least 60 inches high, leave no more than a 2-inch gap at the bottom, block a 4-inch sphere, and have self-closing, self-latching gates that open away from the pool with the latch at least 60 inches high.

When the County issues a building permit for a new or remodeled pool or spa at a single-family home, California's Swimming Pool Safety Act requires at least two of seven approved drowning-prevention features, plus anti-entrapment drain protection. The County applies these state standards through its adopted building codes.

Cannabis retail dispensaries are PROHIBITED in unincorporated San Mateo County. The Board of Supervisors has adopted a ban on all commercial cannabis retail licenses under MAUCRSA. Limited commercial cultivation (mixed-light greenhouse and nursery) is allowed only on parcels designated Agriculture in the General Plan with a County commercial cannabis license. Delivery from licensed operators in other jurisdictions into unincorporated areas is permitted per state law (Bus & Prof Code §26090) and cannot be banned locally.

Unincorporated San Mateo County allows adults 21+ to cultivate up to 6 cannabis plants per residence for personal, non-medical use under County Code Chapter 5.148 (Personal Cultivation). Cultivation must occur inside a private residence or a fully enclosed and secure accessory structure — OUTDOOR personal cultivation is PROHIBITED in unincorporated San Mateo County, going further than state law's baseline. Qualified medical patients may also cultivate indoors. Sale or commercial distribution requires a commercial cannabis license, which the County does NOT issue for retail activities.

Unincorporated San Mateo County does not codify a specific numeric annual cap on garage sales per household, but treats sales as permissible incidental residential use when occasional — typically understood as 2-4 per year. Holding sales with greater frequency or for extended durations can trigger home-business zoning review, require a business license, and constitute an unpermitted retail use of residential property. HOA communities often impose stricter limits (commonly 1-2 per year).

Unincorporated San Mateo County garage sales must stay within reasonable daylight hours, typically 8 AM to 6 PM, and remain within the Chapter 4.88 Noise Control exterior limits at the property line. Friday-Sunday weekend sales are most common. All merchandise, tables, and signs must be removed from public view at the end of each sale day. Leaving items outside overnight can trigger property blight/nuisance enforcement.

Unincorporated San Mateo County does not require a permit for occasional residential garage/yard sales. Sales are treated as incidental residential activity, not commercial operations, so long as they remain occasional and comply with County Code frequency and sign rules. Merchandise must be personal property, not goods purchased for resale — the latter would require a business license and zoning clearance as a home business or retail operation.

The San Mateo County Protected Tree Ordinance (No. 4895) requires replacement planting when a Significant or Heritage Tree is removed under permit. Standard replacement ratios range from 1:1 to 3:1 depending on the DBH and species of the removed tree. Replacement trees must meet minimum size specifications (typically 15-gallon to 24-inch box), be from an approved native/adapted species list, and established for a 2-year maintenance period. When on-site replacement is infeasible, an in-lieu fee is paid to the County Tree Replacement Fund.

The unincorporated County's Protected Tree Ordinance (Chapter 8.400, Ordinance 4895, 2024) requires a Protected Tree Removal Permit before removing protected trees, with replacement planting and a 3-year maintenance period. Exemptions cover dead trees, true emergencies, and specific fire-risk species near structures. A separate Coastal Zone exemption for hazardous trees runs through July 1, 2026.

Under the 2024 Protected Tree Ordinance (No. 4895), San Mateo County designates Heritage Trees based on exceptional size, species rarity, historical significance, or ecological value. Heritage status can be conferred on mature coast live oaks, valley oaks, redwoods, and other native specimens. Removal is rarely permitted except for documented safety emergencies, and damage to a Heritage Tree triggers the most severe penalties under the ordinance, with fines up to $25,000 per tree plus restoration and restitution.

Residential building height limits in unincorporated San Mateo County are set by district. The Planned Agricultural District caps structures at 3 stories or 36 feet, with a 28-foot limit in the Midcoast area. Public and institutional buildings may reach 75 feet with increased yards.

In unincorporated San Mateo County, residential side yards are generally at least 5 feet and rear yards at least 20 feet, while the required front yard is set by the combining 'S' (site) district shown on the Zoning Maps. Setbacks vary significantly by district.

Lot coverage and floor-area limits in unincorporated San Mateo County are district-specific. Several residential districts cap building site coverage at 25 percent and floor-area ratio around 30 percent (or a minimum square-foot allowance), with stricter standards in some areas.

San Mateo County Planning & Building Department requires submittal of an Erosion and Sediment Control Plan prior to issuance of any demolition, grading, or building permit that involves site disturbance. Standard BMPs include silt fencing, straw wattles, erosion control blankets, stabilized construction entrances, and covered stockpiles. Wet-season work (October 1 - April 30) triggers additional inspection requirements and may be restricted on steep slopes. SWPPP required for sites 1+ acre.

Unincorporated San Mateo County is a permittee under the San Francisco Bay Area Municipal Regional Stormwater Permit (MRP 3.0, Order R2-2022-0018) which imposes NPDES Phase I stormwater requirements. Projects creating/replacing 2,500+ sq ft of impervious surface trigger C.3 post-construction stormwater treatment requirements (LID, biofiltration). Illicit discharges to storm drains are prohibited. Construction sites disturbing 1+ acres require SWPPPs and monthly wet-season inspections.

San Mateo County administers its own certified Local Coastal Program (LCP) and issues Coastal Development Permits (CDPs) for projects in the Coastal Zone, which covers roughly 240 sq miles from Devil's Slide south through Pescadero, Año Nuevo, and the Santa Cruz County line. Projects in the Coastal Zone typically require a CDP from County Planning; certain appealable areas (near the shoreline, in sensitive habitat, or in rural areas) can also be appealed to the California Coastal Commission. ESHA (Environmentally Sensitive Habitat Area) buffers, public access, and view corridors are key LCP policies.

San Mateo County requires a Grading Permit from Planning & Building for projects involving more than 250 cubic yards of cut and/or fill, or any grading on slopes over 20%, or grading within 100 ft of a watercourse. Drainage design must direct runoff away from structures and must not adversely redirect water onto neighboring properties. Retaining walls over 4 feet in height need separate engineering and permits. Pre-site erosion-control and tree-protection inspection may be required.

Unincorporated San Mateo County has significant flood risk in coastal lowlands, creek corridors, and bayfront areas. FEMA flood zones require permits, elevation certificates, and flood insurance for federally-backed loans. Sea level rise is a major threat.

Unincorporated San Mateo County uses expedited solar permitting under California AB 2188 (Solar Rights Act). Residential rooftop systems under 10 kW qualify for same-day online permits through SolarAPP+ or the County Building Division. Fire setbacks per CFC Chapter 11B.

California Civil Code §714 (Solar Rights Act) strongly limits HOA authority to restrict solar panels. HOAs in unincorporated San Mateo County (Emerald Hills, West Menlo Park subdivisions) cannot effectively prohibit solar or impose costs over $1,000 or reduce efficiency over 10%.

Mobile food facilities operating in unincorporated San Mateo County must obtain a Mobile Food Facility (MFF) permit from San Mateo County Health Environmental Health Services (EHS), pay the annual permit fee, pass a pre-operational vehicle inspection, secure a commissary agreement with a permitted commercial kitchen, and hold a California Food Handler Card. MFF permits run February 1 through January 31 annually. Contact EHS at (650) 372-6200.

Unincorporated San Mateo County does not designate specific food truck vending zones but restricts operations through general zoning and parking rules. Food trucks may not vend from the public right-of-way for extended periods (not a permitted commercial use), must comply with parking time limits on County roads, and cannot operate within 500 feet of a school during school hours per Education Code §49535.5. Private property vending requires property owner written permission and may trigger a use permit.

San Mateo County Code Chapter 3.04 (Juvenile Curfew Regulations) prohibits minors under 18 from being in public places within unincorporated areas of the County between 11:30 PM and 5:00 AM on weeknights, and between 12:30 AM and 5:00 AM Friday, Saturday, and holiday nights. A daytime truancy curfew applies during school hours. Standard exceptions include minors accompanied by a parent/guardian, traveling to or from work or school activities, or in case of emergency.

San Mateo County parks open at 8:00 A.M. and close at a preset time prior to sunset. Under County Code Section 3.68.080, it is unlawful to remain in any County park or recreation area after the posted closing time without lawful business there.

Outdoor cooking with BBQ grills and propane is generally allowed at residences in unincorporated San Mateo County and is not restricted by the open-burning or Spare the Air wood rules. The California Fire Code regulates where open-flame and LP-gas grills may be used near combustibles and on multifamily balconies.

Backyard smokers and wood/charcoal BBQs are allowed at residences in unincorporated San Mateo County as cooking devices, not regulated open burning. But because smokers burn wood or charcoal, BAAQMD's Spare the Air guidance discourages their use on no-burn days, and the California Fire Code restricts solid-fuel cooking near combustibles and in high fire areas.

In unincorporated San Mateo County, the Planning and Building Code Compliance Section enforces property-maintenance standards and abates public nuisances such as accumulated refuse, junk, and deteriorated structures. When a nuisance is confirmed, the owner gets a Notice and Order to Abate with 10 days to correct; if ignored, the County abates and bills actual costs plus 15%.

Unincorporated San Mateo County does not publish a lawn-height number in its general code, but the County's Notice of Violation forms apply an International Property Maintenance Code standard requiring overgrown and dead weeds and vegetation to be removed and kept at 18 inches or less. Separately, fire-hazardous weeds are abated under California Health and Safety Code authority.

San Mateo County does not appear to publish a dedicated garage-sale ordinance for unincorporated areas, and no County permit requirement for occasional residential sales could be confirmed from a primary source. Sales are treated as an incidental residential activity, but must not create a public nuisance, block sidewalks or roadways, or violate sign and zoning rules enforced by Code Compliance.

Snow sidewalk clearing is not a regular concern in unincorporated San Mateo County's Mediterranean coastal climate, and the County has no dedicated snow-clearance ordinance. On the rare occasions of snow at Skyline Ridge or upper La Honda/Kings Mountain elevations, Caltrans clears State Routes 35, 84, and 92, while property owners are generally responsible for keeping their own driveways and sidewalks (where they exist) passable. Streets & Highways Code §§5610-5618 gives local agencies general authority over abutting-property sidewalk maintenance.

Unincorporated San Mateo County properties used for residential purposes within the Service Area receive a minimum curbside service set by County Code Section 4.04.220, which includes garbage, recycling, and organics carts collected weekly. The County pays the cost of the minimum service levels to the authorized hauler, and those service charges are collected along with the property tax.

There is no special vacant-lot ordinance unique to unincorporated San Mateo County; vacant parcels meet the same public-nuisance and property-maintenance standards Code Compliance enforces countywide. Accumulated refuse, junk, and overgrown or dead vegetation can be declared a nuisance and abated after a 10-day notice, with costs plus a 15% fee billed to the owner.

Recology San Mateo County residential customers receive two free curbside Bulky Item Collection appointments per calendar year, scheduled February 1 through December 31 on the regular collection day. Each appointment accepts a defined set — one large appliance, one bulky item, one e-waste item, and up to twelve 32-gallon bags — with weight and size limits and hazardous/construction exclusions.

In the unincorporated Service Area, County Code Chapter 4.04 establishes mandatory minimum residential collection — garbage, recycling, and organics carts picked up once a week. Recology San Mateo County serves franchised areas including County Service Area 8 (North Fair Oaks); other unincorporated pockets are served by GreenWaste, Republic Services, South San Francisco Scavenger, or Kunz Valley Trash under non-exclusive franchises.

Setout rules in unincorporated San Mateo County are set mainly by the franchised hauler. Recology instructs residents to place carts curbside before 6 a.m. on the service day, wheels against the curb and lid toward the street, spaced about 2 to 3 feet apart facing the same direction. County Code separately requires materials to be contained in transit.

Recycling is part of the mandatory minimum residential service under County Code Chapter 4.04, with single-stream recyclables collected weekly alongside garbage and organics. The County franchise color scheme is gray/black for garbage, blue for recycling, and green for compost. Electronics are banned from the trash, and businesses and multifamily properties must provide recycling containers under state law.

California SB 1383 requires residents and businesses to subscribe to and participate in organics (compost) collection. San Mateo County implements it for the unincorporated area by amending County Code Chapter 4.04, and standard residential service includes a weekly green organics cart for food scraps, food-soiled paper, and yard trimmings. The County conducts required annual compliance inspections.

Unincorporated San Mateo County's Development Code does not set a stand-alone political-sign chapter; temporary signs are addressed within district sign standards. Along state highways, California's Outdoor Advertising Act (B&P Code 5405.3) caps temporary political signs at 32 sq ft, placed no sooner than 90 days before an election and removed within 10 days after.

Unincorporated San Mateo County's Development Code has no separate garage-sale-sign ordinance; signs are addressed through district sign standards that prohibit off-premises and abandoned signs. Signs may not be placed in the public right-of-way, and temporary signs should be removed promptly after the sale.

Unincorporated San Mateo County permits residential holiday decorations without permits. Displays must comply with electrical code, not obstruct public rights-of-way, and respect noise ordinance quiet hours (10 PM to 7 AM). Coastal zone properties may have additional restrictions.

Unincorporated San Mateo County has no countywide dark-sky ordinance, but the Development Code's design standards require exterior lighting to be designed and located so that direct light and glare are confined to the site and directed away from neighbors, with low-level, downward-directed lighting encouraged.

Unincorporated San Mateo County's Development Code requires exterior and interior lighting to be designed and located so that direct rays and glare are confined to the premises. The performance standards state no direct or reflected glare shall be visible, though reasonable shielded security lighting is allowed.

Many San Mateo County cities (Redwood City, San Carlos, others) maintain 'Do Not Knock' registries that residents can join free of charge, and the County Sheriff requires all licensed solicitors to check the registry and respect posted No Soliciting signs before knocking. Unincorporated areas rely primarily on posted signs — a sign reading 'No Soliciting' or 'No Trespassing' on a home, gate, or driveway is legally sufficient to make subsequent solicitation a citable offense under Penal Code §602 and County Code.

Unincorporated San Mateo County requires commercial peddlers and solicitors to obtain a Peddler/Solicitor License from the San Mateo County Sheriff's Office, including a fingerprint-based background check and photo ID badge. Licensed solicitors may operate 9 AM to sunset (or 8 PM, whichever is earlier), must display the County-issued badge visibly, and may not solicit at any address with a posted 'No Soliciting' sign. Religious, political, and charitable canvassing are exempt under First Amendment protections.

Unincorporated San Mateo County applies California's statewide just-cause eviction protections under AB 1482 (Civil Code §1946.2). After 12 months of tenancy, landlords must state an at-fault or no-fault reason. No-fault evictions require one month's rent in relocation assistance.

Unincorporated San Mateo County has NO local rent control. State law AB 1482 (Tenant Protection Act, Civil Code §1946.2 and §1947.12) caps annual rent increases at 5% plus CPI (maximum 10%) for qualifying units. Single-family homes owned by non-corporate owners and buildings under 15 years old are exempt.

Unincorporated San Mateo County does NOT have a rental registration program. Landlords must comply with state habitability laws (Civil Code §1941.1) and the California Building Code. Business license required only for property management companies, not individual landlords.

Commercial drone operations in unincorporated San Mateo County require an FAA Part 107 Remote Pilot Certificate (14 CFR Part 107), LAANC authorization for controlled airspace (most of the Peninsula falls within SFO Class B), and coordination with affected airports (SQL, HAF, PAO, SFO). San Mateo County Parks prohibit commercial drone use; filming permits may be obtainable for specific projects via County Film Commission coordination. Commercial filming in the Coastal Zone may require a Coastal Development Permit.

Recreational drone flight in unincorporated San Mateo County is governed by FAA rules (49 USC §44809, 14 CFR Part 107 exemption) plus a countywide Park Orders ban: drones are PROHIBITED in all San Mateo County Parks (Huddart, Wunderlich, San Bruno Mountain, Edgewood, Pescadero Creek, Memorial, Sam McDonald, Junipero Serra, Crystal Springs). FAA Part 107 registration required for any drone over 0.55 lbs. SFO, Half Moon Bay Airport, San Carlos Airport, and Hayward Executive are nearby controlled airspaces requiring LAANC authorization.