Yuma, AZ Environmental Rules: Stormwater Management (2026)
Key Facts
- Min. residential lot for on-site retention
- 8,000 sq ft
- Max. storage depth
- 8 inches without waiver
- Residential design storm
- 100-year, 24-hr, 3.85 in rainfall
- Commercial/industrial design storm
- 100-year, 1-hr, 2.25 in rainfall
- Retention basin max depth
- 3.5 ft unless approved deeper
- Penalty
- Class 1 misdemeanor, up to $1,000
Summary
Every new lot, plot or parcel in Yuma must hold its own storm runoff on-site: Chapter 192 sets a 8,000-square-foot minimum lot size for on-site retention, an 8-inch maximum storage depth, and design storms up to the 100-year event, enforced by the City Engineer before any building permit issues.
(A) Residential. When on-site retention is utilized in residential subdivisions, the following design criteria shall be applicable: (1) Minimum lot size for on-site retention shall be 8,000 square feet. A deed covenant prohibiting alteration of the final site ground elevations shall be required. The minimum design depth of storm water storage on any lot shall not exceed eight inches except as approved by the City Engineer. (2) The lot depth below the back edge of the sidewalk shall be computed using a 100-year storm of 24-hour duration with 3.85 inches of total rainfall. An allowance for evaporation and/or percolation shall not be incorporated into the computations for minimum lot depth. Storage volume shall also be provided for adjacent streets and alleys except for arterial streets. (3) Each lot shall be provided with an earthen berm around the back and sides of each lot. The earthen berm shall be one foot higher than the adjacent final ground elevation of the lot.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-74: Current through May 20, 2026).
Full Breakdown
Yuma City Code Chapter 192 requires the owner or developer of every lot to provide storage for the total runoff generated by the design storm falling on that parcel, using on-site retention, a retention basin, or a combination of both (§ 192-02, § 192-03). The City Engineer can waive the requirement only when runoff can be directed into a storm sewer, channel or natural drainageway with capacity to carry it to an approved disposal site (§ 192-02(A)). 85 inches of rainfall, with no credit for evaporation or percolation.
Each lot must carry an earthen berm one foot higher than the adjacent final grade. 25 inches on-site, and dry wells may drain the surface but cannot count toward required storage volume (§ 192-05(B)). Retention basins in residential subdivisions are capped at three and one-half feet deep unless the City Engineer approves greater depth, which then triggers a mandatory six-foot masonry fence and locked 16-foot gate (§ 192-04(B)). Filling or substantially altering a lot's surface requires written City Engineer approval and an engineer-prepared drainage plan before Development Services will issue a building permit or certificate of occupancy (§ 192-08).
Violations & Fines
Chapters 192 sections 192-04, 192-05, 192-07 and 192-08 each cross-reference the penalty at § 193-99: any person or corporation violating the chapter is guilty of a class 1 misdemeanor, punishable under § 10-99 by a fine of up to $1,000, imprisonment for up to ten days, or both. The Division of Building Safety will not issue a building permit until the City Engineer confirms an approved drainage plan, and will withhold a certificate of occupancy until construction is verified as substantially compliant.
Frequently Asked Questions
Can I skip building a retention basin on my Yuma lot?
How deep can my yard's stormwater storage be under Yuma's code?
Does grading my own lot in Yuma require city approval?
Sources & Official References
Other rules in Yuma
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