Drainage Assistance Program


PipesOver the years, as development has occurred in unincorporated Marin County, culvert pipes were installed within natural water courses. In most cases, these pipes were installed to simply provide all-weather road access to the development. In other, more rare cases, long stretches of natural water courses were buried in pipes to provide larger areas for building purposes. In either case, these culvert pipes improvements can deteriorate over time and, if not properly repaired, can create significant problems to downstream properties. These culvert pipes are predominantly located within private property and are the private property owner’s responsibility to maintain. However, costs to properly repair deteriorating culverts may be prohibitive and therefore, simply not done, which can heighten risks of damage to public infrastructure. 

To help reduce the risk of damage from these deteriorating culvert pipes, the County Board of Supervisors has authorized the Marin County Department of Public Works to initiate a pilot Private Property Drainage Assistance Program and  has set aside a one-time funding allocation for this pilot program. This pilot program aims to provide financial assistance, up to 50% of the cost of improvements and shall in no case exceed $30,000 ($50,000 for condo units), for homeowners to repair their drainage facilities on their private property that serves the public interest. Projects must meet certain eligibility criteria and conditions to participate in this program. Applications are assessed, and potential funds dispersed, on a first come first served basis.

Contact us - our staff is always available to answer questions and offer assistance as needed.


This pilot program is open to all homeowners within unincorporated  Marin County that have drainage infrastructure on private property that serves the public interest. Storm water drainage systems for roofs, paved areas, or yards that solely benefit the private property owner do not qualify for this pilot program. Driveway culverts also do not qualify for this pilot program. All projects must comply with paying of prevailing wage rates pursuant to Section 1773 of the Labor Code.


  • Proposed project serves the public interest.
  • Proposed project consists of in-place repairs (i.e., slip lining) or excavation and replacement of culvert pipes with a new equal or increased diameter pipe. All driveway culverts are excluded from this pilot program.
  • Property owner agrees to accept a cash contribution, not to exceed fifty percent (50%) of the total cost of the improvements and shall in no case exceed $30,000 per parcel, with the understanding that the County will not design, contract, administer, or exercise dominion or control of the proposed project. Condo units, which does not include apartment units, will be reimbursed at a rate not to exceed fifty percent (50%) of the total cost of the improvements and shall in no case exceed $50,000 per parcel.
  • Property owner agrees to obtain all necessary permits and pay all permit fees associated with the proposed project assessed by the County or any other agency.
  • Property owner agrees that all ongoing maintenance responsibility remains with the property owners.
  • Property owner agrees to indemnify the County against any claim or litigation related to the proposed project and to hold the County harmless for any actions, or lack thereof, related to the submission of a proposal for County contribution, whether or not the proposal is funded.
  • Retroactive applications will be considered if work was completed within the last 90 days of application submittal.


If you have a qualifying drainage project affecting your property, please view the guide below. Applications must be submitted via email. This pilot program is subject to available allocated funding and will be re-evaluated when funding is depleted.

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