Sourced from the OWTS Policy Section 9, State Water Board jurisdiction documentation, and Regional Water Board resolutions — last checked August 2026.
Why LAMPs Exist
California spans redwood coast, Central Valley clay, Sierra decomposed granite, and Mojave desert. A single statewide siting standard conservative enough to be safe everywhere would be needlessly restrictive almost everywhere.
So the OWTS Policy lets a local agency propose its own program. If the Regional Water Board approves it, that program governs new and replacement systems locally.
The state’s framing is that LAMPs “provide an alternate method from Tier 1 programs to achieve the same policy purpose, which is to protect water quality and public health.” Different route, same destination.
What Actually Changes
Siting and design standards. Section 9 is explicit that a LAMP’s standards may differ from Tier 1. That can mean setbacks, soil depth requirements, percolation criteria, or permitted system types.
The flow ceiling rises. Tier 1 caps at 3,500 gallons per day. A LAMP county allows up to 10,000 gpd. On a larger property, that difference alone can determine whether your county can permit the system at all.
ADU permitting gets simpler. A Tier 2 agency may permit ADUs consistent with the LAMP. In a Tier 1 county, any ADU proposal that doesn’t meet Tier 1 has to be referred to the Regional Water Board. See our ADU guide.
The 2023 amendment added flexibility. It clarified that differing design requirements under a LAMP may include alternative collection and disposal systems using subsurface disposal.
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Confirmed LAMP Counties
| County | Detail |
|---|---|
| Monterey | Approved by the Board of Supervisors April 3, 2018 and the Central Coast Water Board May 10, 2018. Applies to permits issued on or after May 11, 2018. County Code Chapter 15.20 was amended to incorporate it. |
| Santa Barbara | Approved LAMP on file with the Central Coast Water Board. |
| San Diego | Approved under San Diego Water Board Resolution R9-2024-0130 — one of the most recent in the state. |
This is not a complete list. LAMPs are approved on an ongoing basis and the state does not publish a single consolidated register. Your county environmental health department can confirm current status in one phone call, and that call is worth making before you assume Tier 1 applies.
California Septic Guide — Free Tool
Which OWTS Tier Are You Under?
California’s OWTS Policy sets five tiers, and which one applies decides your siting standards, your flow ceiling, whether supplemental treatment is required, and whether you can add an ADU. The state publishes the framework but nothing that tells a homeowner where they land.
Directional guidance based on the State Water Board OWTS Policy and its published regional jurisdiction list. Your local agency makes the actual determination, and an approved Local Agency Management Program can set standards that differ from the statewide defaults. Confirm with your county before relying on this.
How to Find Out If Your County Has One
Call your county environmental health department and ask directly: “Does the county have an approved Local Agency Management Program for onsite wastewater?” They will know immediately.
Check your Regional Water Board’s OWTS page. Several publish LAMP status for the counties they oversee. See our permit authority guide for links to all nine.
Look at a recent permit. If a neighbor has installed a system in the last few years, the permit documentation will reference either Tier 1 standards or the county’s LAMP.
What LAMP Counties Have to Do
Worth knowing, because it tells you something about how seriously the program is monitored.
A Tier 2 local agency must report annually to its Regional Water Board by February 1, covering the information in OWTS Policy sections 3.3 and 9.3. It must also:
• Maintain a water quality assessment program under section 9.3.2, submitted every fifth year
• Submit groundwater monitoring data to GeoTracker in electronic deliverable format
• Submit surface water monitoring data to CEDEN
The 2023 amendment changed the assessment cycle from five years after each LAMP’s individual approval date to a fixed five-year cycle beginning in 2018 — so all LAMP counties now report on the same schedule.
If Your County Doesn’t Have One
You’re under Tier 1, the statewide default. That isn’t a problem in itself, but two things follow.
The 3,500 gpd flow ceiling applies, which is the lowest of any tier.
And anything that can’t meet Tier 1 standards has to go to the Regional Water Board rather than being resolved locally. On a difficult site, that adds time and cost.
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Frequently Asked Questions
What is a LAMP?
A Local Agency Management Program — a county or city septic program approved by its Regional Water Board. Where one exists, new and replacement systems are permitted under local standards rather than the statewide default.
Can a LAMP be stricter than the state standard?
Yes, in either direction. Under Section 9, a LAMP siting and design standards may differ from Tier 1. Some are more permissive because local conditions justify it; others are stricter.
Which California counties have a LAMP?
Confirmed examples include Monterey (approved May 2018), Santa Barbara, and San Diego (approved 2024 under Resolution R9-2024-0130). The state does not publish a single consolidated register, so confirm with your county.
Does a LAMP change the flow limit?
Yes. Tier 1 caps at 3,500 gpd; a LAMP county allows up to 10,000 gpd. On a larger property that difference can determine whether the county can permit the system at all.