Environmental Rules in Riverside County, CA (2026)

5 county-level rules, plus city-specific rules for 7 cities in Riverside County, California.

Verified from official government sources

Note: These county rules apply to unincorporated areas of Riverside County. If you live within an incorporated city, that city's own rules apply: see the city list below.

Stormwater Management

Riverside County bans dumping pollutants into streets, storm drains and drainage structures countywide and requires new development to control runoff with approved best management practices.

Riverside County Stormwater Discharge Rules

Some Restrictions

Riverside County Code § 13.12.060

It is a violation of this chapter to throw, deposit, leave, maintain, keep, or permit to be thrown, deposited, placed, left or maintained, any pollutant in or upon any street, alley, sidewalk, storm drain, inlet, catch basin, conduit or other drainage structures, business place, or upon any public or private plot of land in the county.

Full ordinance details →Official source ↗

Erosion Control

Grading, excavation, and earthwork on unincorporated Riverside County land require a permit from the Building Official under County Code § 15.04.080, which enacts Appendix J of the California Building Code with County-specific exemptions and penalties.

Riverside County Grading Permit Required

Some Restrictions

Riverside County Code § 15.04.080

J103.1 Permits required. Except as exempted in Section J103.2, grading shall not be performed without first having obtained a permit therefor from the building official pursuant to all of the permit requirements of this Appendix J. Examples of activities requiring a grading permit includes, but is not limited to, the following: 1.Clearing, grubbing, grading, excavation, stockpiling, earthwork c...

Full ordinance details →Official source ↗

Flood Zones

Riverside County requires a floodplain development permit before any structure, grading, or substantial improvement in a mapped special flood hazard area, with elevation and floodproofing standards enforced under Code Chapter 15.80.

Riverside County Flood Hazard Area Rules

Some Restrictions

Riverside County Code § 15.80.060

Notwithstanding the provisions of any other ordinance to the contrary, within the special flood hazard areas shown on the maps referred to in section 15.80.050, no structure, including flow obstructing structures, shall be constructed, located or substantially improved and no land shall be graded, filled or developed, and no permit or approval shall be granted therefor, unless it complies with ...

Full ordinance details →Official source ↗

Defensible Space

Riverside County enforces 100-foot defensible space around structures in State Responsibility Areas and Local Responsibility Areas, with two clearance zones inspected annually by Cal Fire/Riverside County Fire.

Defensible Space Around Structures

Some Restrictions

California Public Resources Code Section 4291 (Chapter 3. Mountainous, Forest-, Brush- and Grass-Covered Lands)

(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 shall cons...

Full ordinance details →Official source ↗

Flood Elevation Requirements

In unincorporated special flood hazard areas, manufactured homes and pool equipment must sit at least one foot above the base flood elevation, and new buildings near Lake Elsinore need three feet of freeboard above its mapped 100-year water surface.

Riverside County Flood Elevation Freeboard Rules

Some Restrictions

Riverside County Code § 15.80.080(A)(1)(e)

For manufactured homes be elevated above the base flood elevation plus one foot, including any electrical, heating, ventilation, plumbing, and air conditioning equipment and other service facilities servicing the building or attached to the manufactured home to prevent water from entering or accumulating within the components during conditions of flooding.

Full ordinance details →Official source ↗