Modesto, CA Environmental Rules: Erosion Control (2026)

Title 5, Chapter 10, Article 3 governs grading and erosion control citywide. 301 makes it unlawful to grade, fill, excavate, store, or dispose of 350 cubic yards or more of soil, or to clear and grub more than half an acre, without a permit; a separate permit is required for each site unless sites are contiguous, share ownership, and appear in one approved plan. 302 exempts smaller jobs below those thresholds and specific activities like swimming pools and footings under a valid building permit, underground utilities, permitted mining, and planted agricultural crops, though the Director may still condition a building permit on compliance with this chapter.

303 with a local Storm Water Pollution Prevention Plan, engineering plans, specifications, right-of-entry consent, and fees. 304 requires a civil engineer to prepare grading plans showing the site's watercourses, drainage patterns, existing vegetation including all oak trees and trees over 6 inches in diameter, contours at 2-foot intervals on slopes up to 10 percent, and the schedule for erosion and sediment control measures. 204(d) requires sediment and construction waste to be retained on site to the maximum extent practicable, removed the same day if it escapes, and excavated soil piles covered until used or removed; no vehicle washing is allowed on or adjacent to the construction site. 320.