Sewer service fees appear on Marin County Property Tax Statements. The fees charged for residential dwellings and businesses are calculated differently. Business fees are based on water usage. The more water that is used by a business, the more wastewater created for collection by the district and treatment by the sewage treatment plant.
Residential properties are assigned an Equivalent Dwelling Unit (EDU) based upon the actual dwelling units (living units) permitted on the property, regardless of occupancy, as determined by the Marin County Assessor Office records. The 5-year rate plan adopted in May 2014 recognizes the difference in average water usage between single-family and multi-family residences and applies a different per EDU rate for each. Condominiums are included in the multi-family classification.
Ross Valley Residential Rates:
Single-Family = $797 per EDU
Multi-Family = $714 per EDU
Larkspur Residential Sewer Rate:
Single-Family = $1,067 per EDU
Multi-Family = $955 per EDU
Commercial properties are charged the sewer service fee based upon actual winter water usage as reported by MMWD for the billing cycle ended in either January or February of the prior year. The calculation utilizes and average gallon per day for residential usage to convert the MMWD usage into EDUs.
Ross Valley Commercial Rates: $797 per EDU
Larkspur Commercial Sewer Rate: $1,067 per EDU
*IMPORTANT: You should be aware that while your sewer fee appears as one charge on your tax bill, the fee actually funds two separate and independent organizations: Ross Valley Sanitary District, which provides the collection system that delivers wastewater to the treatment plant, and Central Marin Sanitation Agency, which treats wastewater before pumping it into the San Francisco Bay.
Requests for Refunds
If you believe that you have been billed incorrectly for the Sewer Service Charge, you may request a refund within 3 years of the date of the charge in question. Click here to open a refund request form.