Environmental Rules in Imperial County, CA (2026)
4 rules for unincorporated Imperial County, California.
Verified from official government sources
Stormwater Management
Imperial County bans discharging non-stormwater or pollutant-laden runoff into the county's stormwater conveyance system under its NPDES-driven Stormwater Control Ordinance, with limited listed exemptions.
Imperial County Stormwater Discharge Ban
Some RestrictionsImperial County, CA, Land Use Ordinance, Title 9, Division 31, Chapter 2, Sec. 93102.00
Except as provided in Section 93102.01, no person shall discharge, facilitate, cause, permit, or allow to be discharged to the stormwater conveyance system, either directly or indirectly, any of the following: A. Any non-stormwater, except in compliance with the requirements of this division; B. Any stormwater that may cause or threaten to cause a condition of pollution or nuisance, as defined ...
Erosion Control
Imperial County requires a county-engineer grading permit for excavation or earthwork in the unincorporated area, but exempts routine agricultural land leveling.
Imperial County Grading Permit Rules
Some RestrictionsImperial County Code § 91011.00(A),(B)
No person, firm, association, corporation or organization except public entities and their officers, employees or contractors who are performing work within publicly owned rights-of-way, shall, within the unincorporated territories of the County of Imperial, do any grading, excavation or earthwork construction without having first obtained a permit therefore from the county engineer.B.This Chap...
Flood Zones
Imperial County requires a development permit before any construction in a FEMA-mapped special flood hazard area, including land around the Salton Sea at or below 220 feet elevation.
Imperial County Flood Zone Development Rules
Some RestrictionsImperial County Code § 91604.00
A development permit shall be obtained before construction or development begins within any area of special flood hazards or areas of mudslide (i.e., mudflow) established in Section 91603.01. Application for a development permit shall be made on forms furnished by the floodplain administrator and may include, but not be limited to, plans in duplicate drawn to scale showing the nature, location,...
Flood Elevation Requirements
New and substantially improved homes in Imperial County's mapped flood zones must have their lowest floor elevated at least two feet above the base flood elevation: a two-foot freeboard above FEMA's minimum.
Imperial County Flood Elevation Freeboard Rule
Some RestrictionsImperial County Code § 91605.00(C)(1)
Residential construction, new or substantial improvement, shall have the lowest floor, including basement, ... c. In all other zones, elevated at least two feet above the base flood elevation.
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