Landscaping Rules in Altadena, CA (2026)
5 verified landscaping rules for Altadena, California, sourced directly from the municipal code and official government pages.
Verified from official government sources
Grass Height Limits
In Altadena's Very High Fire Hazard Severity Zones, grass and weeds must be kept under 3 inches under LA County Fire Code Title 32 defensible-space rules.
Altadena Grass Height (LA County Fire Title 32)
Some RestrictionsTree Trimming
Trimming protected oak trees (≥8 in DBH) requires an Oak Tree Permit if the work enters the protected zone or removes >25% of crown. Street trees in the public right-of-way are maintained by LA County Public Works.
Altadena Tree Trimming (LA County Code 22.174 + Title 21)
Some RestrictionsCal. Pub. Resources Code Sec. 4291 (Defensible Space - 100-Foot Clearance Requirement)
4291. (a) A person who owns, leases, controls, operates, or maintains a building or structure in the state responsibility area shall at all times do all of the following: (1) (A) Maintain defensible space of 100 feet from each side and from the front and rear of the structure, but not beyond the property line, except as provided in subparagraph (B). The amount of fuel modification necessary sha...
Tree Removal & Heritage Trees
Oak trees (genus Quercus) with a trunk circumference of 25 inches or more (8-inch diameter at 4.5 ft above grade) are protected — removal, damage, or encroachment into the protected zone requires an Oak Tree Permit under LA County Code Chapter 22.174.
Altadena Oak Tree Protection (LA County Code Ch. 22.174)
Heavy RestrictionsWeed Ordinances
LA County Fire's Brush Clearance program also functions as the weed-abatement ordinance — vacant and improved lots must keep weeds and grasses cut to under 3 inches in fire-hazard areas. Annual notices issued each spring.
Altadena Weed Abatement (LA County Code Ch. 21.06 + Fire Title 32)
Some RestrictionsCal. Food & Agric. Code Sec. 5004 (Abatement of Pest, Noxious Weeds, or Diseased Hosts)
5004. “Noxious weed” means any species of plant that is, or is liable to be, troublesome, aggressive, intrusive, detrimental, or destructive to agriculture, silviculture, or important native species, and difficult to control or eradicate, which the director, by regulation, designates to be a noxious weed. In determining whether or not a species shall be designated a noxious weed for the purpose...
Water Restrictions
Outdoor watering in Altadena (served by Lincoln Avenue Water Co., Las Flores Water Co., Rubio Cañon, and Kinneloa Irrigation District) is limited to 2 days per week assigned by address — typically Mon/Thu odd, Tue/Fri even — with 10-minute-per-zone caps.
Altadena Water Restrictions (LA County Waterworks + Foothill MWD)
Some RestrictionsCal. DWR - Model Water Efficient Landscape Ordinance (MWELO, Cal. Code Regs. Tit. 23, Div. 2, Ch. 2.7)
Model Water Efficient Landscape Ordinance Skip to Main Content × Saving your location allows us to provide you with more relevant information. Set Location .cls-1{fill:#fff;stroke-width:0} Share: About Contact Current Conditions Settings × Default High Contrast Reset Increase Font Size Font Decrease Font Size Font Save links on hover --> Menu Contact Search Search this site: Search ...
Looking for Los Angeles County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Altadena city rules.
Landscaping Rules in Los Angeles County →