Larkfield Estates Sewer Extension and Financing Program

    Board Approves Larkfield Sewer Extension

    On Tuesday, June 5th, 2018 the Water Agency's Board of Directors approved the plan to extend sewer service into Larkfield Estates and directed Water Agency staff to develop a financing program to ease the financial burden of sewer construction and connection.


    Meeting Agenda (Agenda Item #45)

     A video of the Board Meeting along with the meeting materials and staff report can be found by visiting:

    Press Release: Board Approves Sewer Extension and Financing Program For Larkfield Estates



    The Airport/Larkfield/Wikiup Sanitation Zone (ALWSZ) is owned and operated by the Sonoma County Water Agency (Water Agency) to collect and treat wastewater.  The Water Agency is planning to (1) make sewer service voluntarily available to current property owners within the ALWSZ boundary that were impacted by the Tubbs Fire, and (2) provide low cost financing for property owners wishing to connect. It is anticipated that sewer service will be available in 2020. 

    Permit Sonoma has indicated on their website that 'properties with compliant septic systems will not compelled to connect' to the new sewer system. For more information please visit the Permit Sonoma website at

    Sewer Service Costs and Financing

    Annual Service Charges

    The current Annual Service Charge for the ALWSZ is currently $901/year for a single family dwelling unit.  This charge must be paid annually by property owners receiving sewer service.  The fee typically increases between 4% and 5% per year.

    Airport/Larkfield/Wikiup Sanitation Zone Connection Fees

    Connection fees ($12,023) owed to the ALWSZ are due upon sewer connection.  The ALWSZ is proposing to provide 20 year, 2% interest assumable loans for property owners impacted by the fire. Loan payments would be about $750/year from year 2020 to 2040.

    Sewer Collection System Construction Costs                                                                    

    It is estimated that the public sewer system will cost about $45,000 to construct per parcel, including laterals up to each property line.  This estimate is conservative meaning that the actual costs may be lower.  The following financing is proposed for current property owners:

    • No interest accrued or payments required until 2030.
    • Property owners would be provided with a 20-year, 2.5% interest assumable loan starting in year 2030. Loan payments would be about $2,750/year from year 2030 to 2050.

    The Connection Fee and Sewer System Construction financing options will be available to property owners who choose to connect before the 90% design phase of the sewer collection system. Loan balances and payment schedule could be transferred to future property owners.

    Future connection to the constructed sewer collection system will be possible, but no financing under this program will be available.  Furthermore, property owners will still owe the sewer construction costs before they are allowed to connect.  Sewer construction costs will increase annually at the SF Bay Regional Construction Cost Index (CCI), which averages around 3%.  Property owners connecting to the sewer at a later date will also be responsible for constructing a sewer lateral from their home to the sewer main in the street, including the repaving that must follow construction.

    There is no requirement to connect to the sewer upon transfer or sale of the property.  Current and future property owners could voluntarily connect and pay the connection fee and sewer construction costs.

    Key Updates

    • (6/18/18) June 2018 Community Update - Updates about the hiring of a sewer collection system design consultant, an estimated sewer design timeline,  financing loan order, and a new Water Agency point-of-contact.
    • (4/3/18) Temporary Holding Tank Information from Permit Sonoma - Permit Sonoma has released information describing how temporary holding tanks may be used by homes that plan to connect to sewer service after sewer service becomes available.  The use of temporary holding tanks will allow property owners to build in the footprint of their existing septic system and inhabit their home even if sewer service is not yet available.  For more information please visit the Permit Sonoma website at
    • (3/22/18) Point of Sale Requirement Removed - Based on recent feedback, the Water Agency has removed the point of sale requirement under this revised proposal. The revised proposal, outlined below, does not require connection to the sanitation system at the time of sale or transfer of property ownership.  There is no requirement to connect to the sanitation system under this proposed program.
    • (3/22/18) Assumable Loans – Based on recent feedback, the Water Agency is working to make all loans associated with this program assumable and transferrable to new property owners.

    Next Steps

    Information about how to sign-up to have sewer service extended to your property will be made available shortly. 

    To ensure that you will be successfully contacted as information becomes available, please provide Water Agency Senior Program Specialist Barry Dugan (contact information below) with your contact information and property address.

    Questions or comments? Contact Barry Dugan at or 707-547-1930.