Residential rates are designed to cover the actual cost of service. Each residential unit is charged the basic flat rate, $1,233 as of July 1, 2023. This applies to single-family homes, apartments, condominiums and other multi-family dwellings, and mobile home and trailer parks.
Non-residential rates are structured individually for each type of non-residential use. To determine an estimated cost to collect and treat wastewater from a non-residential customer, the District calculates the cost based on water usage and a strength factor, which is an average cost to treat wastewater from a particular type of non-residential customer. Thus, a low water user would pay less than a high water user in the same category of non-residential customers with the same strength factor. And, for two non-residential customers with the same water use, the one with the higher strength factor would pay more.
For calculating the non-residential rate, the District obtains an average of winter and summer water usage for each non-residential customer from the Marin Municipal Water District. Excluded is water used solely for irrigation and recycled water that does not enter the District’s sewer system, i.e. water not used for toilet flushing, laundry, commercial car washes, etc.
The average water usage is converted into sanitary units. Each eight (8) hundred cubic feet (CCF) is equal to 5,984 gallons and is equal to one sanitary unit.
|Water Use Calculation
|Domestic strength users:
|These customers include (but are not limited to): Commercial, office buildings, retail, churches, halls, public agencies, laundromats, service stations, medical offices, hospitals, convalescent/nursing homes, barber/beauty shops, and car washes
|The non-residential sewer service charges account for sewer strength and are based on monthly water usage. The District obtains the average of winter and summer monthly water usage for each non-residential customer
|Elevated strength users:
|from the Marin Municipal Water District. This data is then divided by 8 ccf (hundred cubic feet) in order to convert the usage to equivalent single family residential units
|These customers include (but are not limited to): hotels with food, commercial laundry, and mixed use.
|(also known as “sanitary sewer units” or “SSUs”). The bill is calculated by multiplying the applicable sewer service charge by the number of SSUs. Each account shall pay a minimum of one (1) SSU. Rates are per SSU per year.
|High strength users:
|These customers include (but are not limited to): restaurants, markets with food waste disposal, and bakeries.
|Water which does not enter the sewer system, such as water not used for toilet flushing, laundry, and car washes, is excluded from the calculation.
|Industrial and other higher-strength users
|Contact the District for information and assistance
|Schools without showers or cafeteria facilities
|0.01 times the annual domestic sewer service charge rate per average daily attendance for students, faculty, and employees.
|Schools with showers or cafeteria facilities
|0.02 times the annual domestic sewer service charge rate per average daily attendance for students, faculty, and employees.
For information on the specific rates for individual non-residential customers, contact Dale McDonald at the District office at (415) 526-1519.