Environmental Rules in Norwalk, CA (2026)
4 verified environmental rules for Norwalk, California, sourced directly from the municipal code and official government pages.
Verified from official government sources
Stormwater Management
Norwalk bans illicit connections and non-stormwater discharges into its municipal storm drain system under Chapter 18.04, from dumping yard waste in a catch basin to washing cars anywhere but a commercial car wash. The Director of Community Development enforces it as the city's MS4 permit compliance program.
Norwalk Stormwater Discharge Prohibitions
Significant RestrictionsNorwalk, CA, Municipal Code § 18.04.070(A), (E)
A. Illicit Discharges and Connections. It is prohibited to commence, establish, use, maintain or continue any illicit connections to the MS4 or any illicit discharges to the MS4. ... E. Car Washing. No motor vehicle, boat, trailer, or other type of mobile transportation may be washed, other than at a commercial car wash, unless such vehicle is being washed by: 1. A resident at their residence u...
Erosion Control
Norwalk requires an approved erosion and sediment control plan before a discretionary permit issues for hillside grading or any project disturbing an acre or more of land. New single-family hillside homes must specifically protect slopes and channels and route runoff to vegetation before discharge.
Norwalk Hillside Grading Erosion Rules
Significant RestrictionsNorwalk, CA, Municipal Code § 18.04.040 (Hillside definition); § 18.04.105(C)(1)(f)(i)
"Hillside" means property located in an area with known erosive soil conditions, where the development contemplates grading on any natural slope that is 25% or greater and where grading contemplates cut or fill slopes. ... A new single-family hillside home development project shall include mitigation measures to: (A) Conserve natural areas; (B) Protect slopes and channels; (C) Provide storm dra...
Flood Zones
Norwalk requires a development permit before any construction, grading, filling or manufactured-home placement within a FEMA-mapped special flood hazard area. The City Manager, serving as Floodplain Administrator under Chapter 15.48, reviews every application against the 2008 Flood Insurance Study and Rate Maps before work in the floodplain can proceed.
Norwalk Floodplain Development Permit
Some RestrictionsNorwalk, CA, Municipal Code § 15.48.080 (Establishment of development permit); § 15.48.090 (Restrictions); § 15.48.040 (Compliance)
A development permit shall be obtained for all proposed construction or other development, including the placement of manufactured homes, so that it may be determined whether such construction or other development is within a special flood hazard area. ... No development within a special flood hazard area shall be allowed unless the applicant has obtained all necessary permits from those govern...
Flood Elevation Requirements
New construction and substantially improved buildings inside Norwalk's mapped flood hazard area must have their lowest floor built at or above the base flood elevation shown on the City's Flood Insurance Rate Map. Non-residential buildings get one alternative: full dry floodproofing engineered to resist hydrostatic and hydrodynamic loads.
Norwalk Base Flood Elevation Standard
Some RestrictionsNorwalk, CA, Municipal Code § 15.48.020 (Definitions, base flood elevation); § 15.48.110(G),(H) (Construction standards)
"Base flood elevation" means the elevation shown on the Flood Insurance Rate Map for Zones A that indicates the water surface elevation resulting from a base flood. ... The lowest floor (including the basement) of all new construction and substantial improvements of residential structures shall be elevated to or above the base flood level. ... The lowest floor (including the basement) of all ne...
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