Downey, CA Environmental Rules: Erosion Control (2026)
Key Facts
- Governing section
- Downey Municipal Code § 5704
- Required permits
- Construction General Permit or Industrial General Permit
- Required on-site records
- NOI/WDID number, SWPPP, water quality data
- Related BMP duties
- § 5705 covers all parcels, not just permitted sites
- Penalty
- Misdemeanor; each day is a separate offense
Summary
Any construction, commercial or industrial project in Downey that needs a state NPDES stormwater permit must have it before work starts. Municipal Code § 5704 requires keeping the Construction General Permit, a site-specific SWPPP and stormwater quality data on hand for inspection, so erosion and sediment controls are documented, not optional.
§ 5704. CONTROL OF POLLUTANTS AND RUNOFF FROM SITES REQUIRING A STORMWATER ACTIVITIES PERMIT. (a) It shall be a violation of this chapter for any person or entity, required by governmental law to obtain a NPDES stormwater activities permit, to conduct a construction, commercial, or industrial activity in the City of Downey, without the appropriate Construction General Permit (CGP) or Industrial General Permit (IGP). (b) Any person or entity, required to have an NPDES stormwater activities permit for a parcel within the City of Downey, shall retain at said parcel the following evidence of compliance with the CGP or IGP and make said documents available upon request from an Authorized Enforcement Officer: (1) a copy of the submitted Notice of Intent (NOI) to comply with State Stormwater Waste Discharge Requirements or a waste discharge identification (WDID) number issued by the SWRCB; (2) a SWPPP; and (3) site specific storm water quality data.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4807734; v5 updated 2026-01-27).
Full Breakdown
Section 5704 of the Downey Municipal Code, inside the Storm Water and Urban Runoff Pollution and Conveyance Controls chapter, targets erosion and sediment control at active construction sites by tying local code enforcement to the state's Construction General Permit (CGP) and Industrial General Permit (IGP) programs. Subsection (a) makes it a violation of the chapter for any person or entity required by state law to obtain an NPDES stormwater activities permit to conduct construction, commercial or industrial activity in Downey without the appropriate CGP or IGP already in hand, meaning grading and site work cannot lawfully start before that state permit is secured.
Subsection (b) requires anyone holding a required NPDES permit to keep specific compliance records on site and produce them on request from an Authorized Enforcement Officer: a copy of the submitted Notice of Intent or a waste discharge identification number from the State Water Resources Control Board, a Storm Water Pollution Prevention Plan (SWPPP), and site-specific stormwater quality data. The SWPPP is where erosion and sediment control measures actually get specified, defined elsewhere in the chapter as the plan identifying potential pollutant sources and describing the design, placement and implementation of Best Management Practices to prevent non-stormwater discharges and reduce pollutants during covered construction activities.
Related BMP obligations in § 5705 apply to every parcel in the City, not just permitted construction sites, and separately bar dumping, spilling or discharging solid or liquid waste onto any premises or into the MS4, prohibit uncovered outdoor storage of unsealed building materials that could wash into storm drains, and require monthly or quarterly vacuum sweeping of parking lots above certain size thresholds. Section 5704(d) closes the loop by barring anyone from obfuscating or concealing the nature of a construction, commercial or industrial site to dodge the permit requirement in the first place.
Violations & Fines
Conducting construction, commercial or industrial activity requiring an NPDES permit without the CGP or IGP, or failing to keep the required Notice of Intent, SWPPP or stormwater quality data on site for inspection, violates § 5704 and § 5710. Enforcement runs as a misdemeanor under Chapter 2 of Article I of the code, with each day of noncompliance a separate offense, plus potential civil injunctions and cost recovery for the City's investigation and cleanup expenses.
Frequently Asked Questions
Does a Downey construction project need a stormwater permit before grading starts?
What paperwork does a Downey contractor keep on site for stormwater compliance?
Do erosion control rules apply to sites that don't need a state stormwater permit?
Sources & Official References
Other rules in Downey
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