Marin County homeowners who rely on septic systems could see simpler rules, lower costs and more flexibility under a regulatory overhaul heading to the Board of Supervisors on Tuesday, Nov. 10.

Chris Choo, assistant director of the Community Development Agency, will present the county’s progress on updating its Local Agency Management Program, the framework that governs permitting for onsite wastewater treatment systems, commonly called septic systems. More than 6,000 residential, agricultural and business parcels across the county depend on them, according to a staff report prepared for the meeting.

The presentation is informational. Staff expects to bring recommended code and manual changes to the board in early 2027.

Why it matters

Without a locally tailored LAMP, Marin could become subject to statewide requirements that the county says are less suited to its varied terrain, small lots and proximity to sensitive waterways, according to the county’s septic regulations update page.

The county says it currently operates as a Tier 2 local agency while developing the updated program. It has been working on the update since 2014, but staffing changes and shifting state requirements delayed progress.

New septic systems can cost tens of thousands of dollars to well over $100,000, the staff report notes. Homeowners often encounter the rules when applying for a building permit, adding a bedroom or building an accessory dwelling unit.

What residents asked for

The Community Development Agency hosted 46 community, one-on-one and stakeholder meetings from March through June and collected more than 450 comments, according to a county news release. The broader engagement effort, including ongoing work with industry professionals, reached more than 500 participants across nearly 60 meetings, the staff report states.

Residents, business owners and ranchers described confusing rules, fear of the permit process and frustration with costs, the staff report states. Requests included greater flexibility, more approved technologies, improved customer service and help paying for repairs.

“We are grateful for their partnership and are eager to finalize the regulations that will provide an easier, more flexible process while protecting our environment and communities,” Choo said in the county news release.

Proposed changes

The staff report identifies several areas where county staff and San Francisco Bay Regional Water Quality Control Board staff have found common ground:

  • A process for approving additional wastewater technologies, including composting and other waterless toilets.
  • Revised system-capacity and location standards that could allow some existing systems to accommodate an additional bedroom or ADU.
  • Options for bringing unpermitted systems into compliance and completing repairs in stages.
  • Fewer testing and inspection requirements, with licensed professionals able to document qualifying work without a county inspector attending.

The changes still require formal approvals before implementation.

Unresolved questions

Several issues remain open. The Regional Water Board has requested septic inspections at the time of property sales. The county and the board still need to settle minimum lot sizes for new development, rules for small shared systems and the scope of waivers for agricultural land, the staff report states.

Staff plans to address customer service, permitting information and access to property records as the code and manual are finalized, with improvements brought forward throughout 2027. Financial assistance options will be researched after adoption; new assistance is not yet assured.

The Nov. 10 board meeting begins at 9 a.m. The septic update is listed as a study session.

The county requested written comments by noon Monday, Nov. 9, for advance distribution to supervisors. Residents can also comment during the meeting in person or remotely, following the county’s participation instructions.