Stormwater Component and Credits

Stormwater runoff is rain that flows off sidewalks, rooftops, parking lots, and driveways, while collecting pollutants along the way. 

Stormwater management is a critical municipal responsibility with a direct impact on public health and safety, environmental habitat, and future development. Our combined sewer system does a good job collecting and treating both stormwater and wastewater. The stormwater component covers the cost of stormwater-specific infrastructure and the stormwater portion of the combined sewer system. 

The structure splits the sewer portion of your bill into two parts so that each individual customer pays based on 1) their wastewater discharge, and 2) their property’s stormwater runoff. 

PREVIOUS - Based on one general measurement: Sewer Flow (wastewater and stormwater combined) 

CURRENT - Based on two more specific measurements:   

1. Wastewater Flow
2. Stormwater Runoff 

The stormwater component is calculated based on property size and the area of paved or impermeable surfaces that are unable to absorb excess rain. This is a more accurate method of calculating each customer’s contributions to the combined sewer system and allows you to take charge of your bill by implementing sustainable stormwater practices that divert stormwater from the sewer system, such as rain gardens, permeable pavement, living roofs, and rainwater harvesting.  

Customers will fall into one of two categories for the stormwater component: 

1. Simplified residential rate:  a three-tiered structure for residential customers, based on the total assessor’s parcel size, with flat rates for each. Smaller parcels are billed a lower rate, with rates gradually increasing for larger parcels.  
2. Standard rate:  commercial, institutional, industrial, mixed-use land use, and large multi-family, residential parcels (over 6,000 square feet or with more than six dwelling units) would be billed based on the total permeable and impermeable surface areas of a specific parcel.  

Details on the simplified residential rates and standard rates can be found on our Prop 218 page. 

Permeable surfaces, like planters and lawns, can absorb some stormwater when it rains. Impermeable surfaces, like driveways and roofs, direct more water to — and impose more costs on — the sewer system. 

The change is more equitable for our customers because it ensures that each customer pays their fair share for the combined sewer system.  

The wastewater portion of your bill is now based on the estimated volume of wastewater discharged. The stormwater component is based on the estimated amount of stormwater that flows off each property, including the property's area and surface types. This updated methodology is a standard practice among many utilities nationwide. 

The new rate structure is a reallocation of an existing charge and not a new fee. The stormwater component will increase sewer bills for some customers and decrease them for others, depending on the size and characteristics of a property. The amount of permeable or impermeable surface on each property is a key factor: properties with a large area of impermeable surface are more likely to see an increase in their sewer bill. To minimize the immediate impact on our customers’ bills, the stormwater component will be phased through 2030. 

Use our bill calculator to calculate your bill, including your stormwater component. Make sure you have a copy of your bill to help you with filling out the fields. 

Stormwater Credits 

As part of the new rates package, the SFPUC is also implementing a stormwater credit. Customers who capture stormwater on their property using green infrastructure to help improve the performance of the sewer system can apply for this credit.  Customers that have green infrastructure on their property will be eligible to apply for a monthly credit on their bill. We will calculate credits based on the area of a property that drains to green infrastructure when it rains. Larger green infrastructure projects that capture more stormwater over a larger area would receive larger credits. You may apply for a stormwater credit with the Stormwater Credit Program.  

The SFPUC offers various grants to provide funding to our customers to help build green infrastructure on their properties. You can learn more at https://sfpuc.gov/programs/grants:

• Green Infrastructure Grant Program: Large public and private properties may be eligible for the SFPUC’s Green Infrastructure Grant Program. The program funds the design and construction of green stormwater infrastructure (like rain gardens, permeable pavement, and rainwater harvesting systems), to help reduce stormwater runoff and lower the stormwater portion of your bill. Projects can receive grants of up to $2 million.  
• Green Infrastructure for Homes: San Francisco homeowners may be eligible for a limited pilot program to receive grant funding to install stormwater management features, such as rain gardens, permeable pavement, and cisterns.  

Other Opportunities for Bill Savings 

Check out the SFPUC’s programs, rebates and incentives to find out resources to help reduce your water and sewer bills.