Environmental Rules in Modesto, CA (2026)
4 verified environmental rules for Modesto, California, sourced directly from the municipal code and official government pages.
Verified from official government sources
Stormwater Management
Modesto's Storm Water Management and Discharge Controls Ordinance bans any non-storm-water discharge into the City's municipal storm drain system unless an NPDES permit or listed exception applies, and specifically prohibits roof drains emptying onto sidewalks and pool or spa water entering storm drains. Violators face civil penalties up to $25,000 per day and misdemeanor prosecution.
Modesto Storm Drain Discharge Rules and Penalties
Significant RestrictionsModesto Code of Ordinances § 5-10.201
(a)Illicit Discharge. Any illicit discharge to the City's MS4 is prohibited unless excepted by Section 5-10.202. All discharges to the City's MS4 of material other than storm water must be in compliance with an NPDES permit issued for the discharge or other regulatory requirement issued pursuant to the Porter-Cologne Water Quality Control Act if an NPDES permit is not required or applicable.(d)...
Erosion Control
Modesto requires a Grading and Erosion Control Permit before moving 350 cubic yards or more of soil or clearing more than half an acre of land. The Public Works Department reviews plans prepared by a civil engineer and can suspend or revoke permits for noncompliance under Modesto Code of Ordinances § 5-10.301.
Modesto Grading and Erosion Control Permit Rules
Significant RestrictionsModesto Code of Ordinances § 5-10.301
(a)Except as provided by Section 5-10.302, it is unlawful for any person to (1) grade, fill, excavate, store or dispose of three hundred fifty (350) cubic yards or more of soil or earth material; or (2) clear and grub more than one-half (.5) acre of land within the City without a grading and erosion control permit. A separate permit is required for work on each site unless sites are contiguous,...
Flood Zones
Any construction, grading, filling, or other development inside a special flood hazard area in Modesto requires a building permit before work begins. The Floodplain Administrator, who is the Chief Building Official, reviews every application against FEMA's Flood Insurance Study and Rate Maps and can deny a project that would raise the base flood level.
Modesto Floodplain Development Needs a Permit
Significant RestrictionsModesto Code of Ordinances § 9-4.403
A building permit shall be obtained before any construction or other development, including manufactured homes, begins within any special flood hazard areas. Application for a building permit shall be made on forms furnished by the Chief Building Official. The application requirements shall include but not be limited to the following information: ... (4)Location of the regulatory floodway when ...
Flood Elevation Requirements
New and substantially improved homes in a Modesto special flood hazard area must have the lowest floor elevated to or above the base flood elevation shown on the FEMA rate maps. The code sets that BFE line as the floor, with no added freeboard margin, and requires a registered engineer or surveyor to certify the finished elevation.
Modesto Base Flood Elevation Standard, No Freeboard
Some RestrictionsModesto Code of Ordinances § 9-4.501(c)(1)
Residential Construction. All new construction or substantial improvements of residential structures shall have the lowest floor, including basement: (i) In AE, AH, A1-30 zones, elevated to or above the base flood elevation; (ii) In an A zone, without BFE's specified on the FIRM (unnumbered A zone), elevated to or above the base flood elevation, as determined under Section 9-4.402(c). Upon the ...
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