Gilroy, CA Landscaping Rules: Rainwater Harvesting (2026)
Key Facts
- Governing section
- Gilroy City Code § 30.38.220
- Mandatory element
- On-site rainwater retention BMPs required
- Design standard
- 24-hour or 85th percentile rain event capacity
- Listed method
- Rain gardens, cisterns, catchment systems
- Related chapter
- Chapter 27D post-construction stormwater rules
Summary
In the City of Gilroy, qualifying landscape and grading design plans must implement storm water best management practices that increase on-site rainwater retention and infiltration under Gilroy City Code § 30.38.220. Section 30.38.220(e)(5) lists incorporating rain gardens, cisterns, and other rain harvesting or catchment systems as one accepted way to meet that mandatory capture-and-reuse standard.
(a) Storm water management practices minimize runoff and increase infiltration which recharges groundwater and improves water quality. Implementing storm water best management practices in the landscape and grading design plans to minimize runoff and to increase on-site rainwater retention and infiltration is required. ... (e) Storm water projects shall incorporate any of the following elements to improve on-site storm water and dry weather runoff capture and use: ... (5) Incorporate rain gardens, cisterns, and other rain harvesting or catchment systems.
Full Breakdown
Article XXXVIII's storm water provisions apply to the same qualifying landscape projects covered by Gilroy's Water Efficient Landscape Ordinance: new landscape additions of 500 square feet or more and rehabilitations of 2,500 square feet or more, installed after December 1, 2015, under § 30.38.20. Section 30.38.220(a) makes implementing storm water best management practices in the landscape and grading design plans mandatory, stating it is required to minimize runoff and increase on-site rainwater retention and infiltration. Subsection (d) sets the numeric design target: landscape areas must be designed with capture and infiltration capacity sufficient to prevent runoff from impervious surfaces during either a twenty-four hour rain event or the eighty-fifth percentile twenty-four hour rain event.
Subsection (e) requires storm water projects to incorporate elements from a list that includes grading impervious driveways to drain to vegetated areas, minimizing impervious surface area, using pervious or porous paving, directing roof and paved-surface runoff into planting beds, and, at item (5), incorporating rain gardens, cisterns, and other rain harvesting or catchment systems. Subsection (c) cross-references § 30.38.120's friable-soil requirement to maximize retention. Applicants must also consult Chapter 27D and the South Santa Clara County Regional Stormwater Management Guidance Manual referenced in subsection (b) for the technical low impact development standards Community Development applies when reviewing the plan.
Violations & Fines
A landscape or grading design plan that omits required storm water capture and infiltration measures, or that fails to meet the twenty-four hour retention capacity standard of § 30.38.220(d), is noncompliant with Article XXXVIII and enforced under § 30.38.260 through Article LIII's Zoning Ordinance enforcement chapter, which authorizes Community Development to issue an administrative citation under Chapter 6A before the plan is approved.
Frequently Asked Questions
Does Gilroy require rain barrels or cisterns on every property?
Which Gilroy projects must meet the rainwater retention standard?
What is Gilroy's numeric design target for rainwater capture?
Sources & Official References
Other rules in Gilroy
California rules heatmap·Compare Gilroy to another location·View the California landscaping rules overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.
Rainwater Harvesting in Nearby Cities
How other cities in Santa Clara County handle rainwater harvesting.