Alameda County, CA Landscaping Rules: Rainwater Harvesting (2026)
Key Facts
- State authorization
- AB 1750 (2012)
- Permit-free
- Under 5,000 gallons surface
- Large systems
- Plumbing permit required
- Rebates
- EBMUD, ACWD offer
- Use
- Non-potable landscape
Summary
Rainwater harvesting is legal and encouraged in Alameda County under CA Rainwater Capture Act of 2012 (AB 1750). Rain barrels under 5,000 gallons for landscape irrigation generally need no permit.
Use of rainwater collected from rooftops does not require a water right permit pursuant to Section 1201. ... "Rainwater capture system" means a facility designed to capture, retain, and store rainwater flowing off a building rooftop for subsequent onsite use. ... Notwithstanding any other provision of this chapter, a landscape contractor working within the classification for which the license is issued may enter into a prime contract for the construction of... (4) A rainwater capture system, as defined in Section 10573 of the Water Code, used exclusively for landscape irrigation or as a water supply for a fountain, pond, or similar decorative water feature in a landscaping project.
Full Breakdown
Rainwater harvesting is broadly legal and encouraged in Alameda County under the California Rainwater Capture Act of 2012 (AB 1750), which allows residential, commercial, and governmental landowners to install, maintain, and operate rainwater capture systems without a water-rights permit. Small rain barrels and above-ground tanks under 5,000 gallons used solely for landscape irrigation generally require no building permit. Larger cisterns, underground tanks, or pressurized systems connected to plumbing require building or plumbing permits and backflow prevention per the California Plumbing Code. EBMUD and ACWD both offer rebates for rain barrels and cisterns as part of conservation programs. Harvested rainwater may be used for landscape irrigation, toilet flushing with appropriate treatment and permitting, and other non-potable uses. Greywater and rainwater must be kept separate; cross-connection controls are required if connected to the domestic plumbing.
Frequently Asked Questions
Can I drink harvested rainwater?
Are rebates available?
Sources & Official References
Other rules in Alameda County
California rules heatmap·Compare Alameda County to another location·View the California landscaping rules overview
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