Fairfield, CA Environmental Rules: Erosion Control (2026)
Key Facts
- Max slope
- 2:1 (horizontal:vertical) unless engineered
- Stabilization deadline
- Before Oct 15 rainy season start
- Enforcing agency
- City Engineer
- Permit trigger
- Grading permit plus performance bond
- Guidance manual
- ABAG Erosion & Sediment Control Manual
Summary
Fairfield's Grading and Erosion Control article, City Code Section 25.247, requires every grading project to protect cut and fill slopes from erosion, cap slope steepness at 2:1, and stabilize exposed soil before the October 15-April 15 rainy season. The city engineer enforces the standard through the grading permit process.
(a) Slopes. The faces of cut and fill slopes shall be prepared and maintained to control against erosion. This control may consist of effective planting. If planting is required by the city engineer or as a condition of approval of the tentative map, the planting plan shall be approved by the city's architectural approval committee. The protection for the slopes shall be installed as soon as practicable and prior to calling for final approval. Where cut slopes are not subject to erosion due to the erosion-resistant character of the materials, such protection may be omitted. ... Soil exposure to erosion by removal of vegetation shall be limited to the smallest area practical and for the shortest time practical. Soil exposure shall not exceed an area in which development can be completed during a single construction season to ensure that soils are stabilized and vegetation is established well in advance of the rainy season (October 15 - April 15). ... Slopes, both cut and fill, shall not be steeper than two horizontal to one vertical (2:1), unless a thorough geological and engineering analysis indicates that steeper slopes are safe and appropriate erosion control measures are specified.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4962673; v0 updated 2026-02-17).
Full Breakdown
248), which the city engineer administers alongside the grading permit and bond process. Every graded slope must be planted or otherwise protected against erosion as soon as practicable and before the city signs off on final approval; where the city engineer requires planting as a permit condition, the planting plan needs sign-off from the city's architectural approval committee. Where cut slopes are erosion-resistant by nature, that planting requirement can be waived. 247(c) sets sixteen numbered design standards that apply citywide: soil exposure from grading or vegetation removal must stay within an area that can be finished in a single construction season, sediment basins and traps must go in before any clearing begins and stay in place until the city engineer authorizes removal, and temporary seeding or mulching must protect exposed ground through the October 15-April 15 rainy season.
Cut and fill slopes cannot exceed a 2:1 (horizontal to vertical) ratio unless a geotechnical and engineering analysis justifies a steeper cut with added erosion controls. Developers must also keep cuts and fills out of natural watercourses and floodplains, divert runoff away from denuded slopes, and file a written contingency plan for unexpected rain or best-management-practice failure. Fairfield cross-references the Association of Bay Area Governments' Manual of Standards for Erosion & Sediment Control Measures for design specifics. 245 lets the city engineer require a bond or cash deposit to guarantee the work is corrected if it isn't finished to the approved plans.
Violations & Fines
Grading without the required erosion controls exposes a project to a stop-work order from the city engineer under Section 25.244's permit conditions, and the city may draw on the performance bond required under Section 25.245 to complete or correct unfinished slope protection. Section 25.248 gives the city engineer inspection authority over every active grading site, including special inspection and testing, and can require design or operational changes mid-project if weather-driven erosion problems appear that weren't accounted for when the permit issued.
Frequently Asked Questions
Does Fairfield require an erosion control plan for grading projects?
How steep can a cut or fill slope be in Fairfield?
What happens if erosion controls fail during a Fairfield construction project?
Sources & Official References
Other rules in Fairfield
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Erosion Control in Nearby Cities
How other cities in Solano County handle erosion control.