On July 1, 2024, City of Portland sewer, stormwater, and water utility customers saw changes to their sewer and stormwater rates and charges for connecting to the sewer. Learn more about those changes at Changes to Environmental Services Rates and Charges.
The Difference Between the Sanitary Sewer and Stormwater System
The sanitary sewer and stormwater systems are two very different systems, which is why we charge them separately on your City of Portland utility bill.
- The sanitary sewer system is a network of pipes and pump stations that transport wastewater from households and businesses to wastewater treatment facilities.
- The stormwater system is a collection of storm drains, pipes, ditches, outfalls, natural areas, and green streets that prevent pollution and reduce flooding by collecting and holding rainwater runoff. It allows it to soak into the ground or carries it to a stream, river, or wastewater treatment facility.
Understanding Your Rates and Charges
Sanitary sewer: Residential single-family or multi-family sanitary sewer charges are calculated using actual water flow, class average flow, or winter average flow. Residential customers are billed the winter average or actual water consumption during those billing periods, whichever is less. Non-residential sanitary sewer charges use actual water consumption.
Actual water: The water consumption is measured through your water meter.
Class average: The average water consumption for a specific account class, such as single or multi-family residential. Class average is used when there is no water use history or when a winter average is unavailable.
Winter average: The average water consumption between December 1 and April 30 for monthly billing cycles or January 1 and April 30 for bi-monthly billing cycles. For more information on winter average, visit the How to Calculate Your Winter Average section on this page.
Stormwater service unit: Stormwater service units refer to the number of dwelling units on the property. Single-family residential properties with one dwelling unit have one stormwater service unit. Residential properties with two dwelling units, such as one house and one ADU, have two stormwater service units. Those with three or more dwelling units will be billed 0.65 stormwater service units for each dwelling unit. Non-residential customer stormwater service units are calculated by dividing the stormwater billable area by 2,400 square feet.
Stormwater billable area: Stormwater billable area is the developed area of a property. Development prevents stormwater from flowing naturally or soaking into the ground. This includes areas like rooftops, porous pavement, patios, and driveways. Single-family residential properties are placed into a small, standard, or large category based on the developed area on their property.
Residential Rates
Sanitary sewer: $12.69 per 100 cubic feet of water use
Stormwater service unit: $5.76 per service unit per 30 days
Stormwater billable area: $13.68 per 1,000 square feet of stormwater billable per 30 days
- Small category: properties with 1,500 square feet or less of stormwater billable area are billed at 1,200 square feet.
- Standard category: properties with 1,501 to 2,700 square feet of stormwater billable area are billed at 2,400 square feet.
- Large category: properties with (2,701 or more square feet of stormwater billable area are billed at 3,600 square feet.
Residential Customer Calculation Example 1
The example below is for a single-family residential customer who used 12 ccf (one ccf equals 100 cubic feet), has one dwelling unit, is in the standard category, and is billed quarterly.
| Charge | Calculation | Total |
|---|---|---|
| Sanitary sewer | $12.69 x 12ccf | $152.28 |
| *Stormwater service unit | $5.76 x 3 | $17.28 |
| **Stormwater billable area | ($13.68 x 2.4) x 3 | $98.50 |
| Total sewer and stormwater charges | $268.06 |
*The stormwater service unit rate is per 30 days. In the calculation above, it is multiplied by three to represent a 90-day or quarterly billing period.
** The stormwater billable area rate is per 1,000 square feet per 30 days. In the calculation above, the rate is first multiplied by 2.4 (standard category is billed at 2,400 square feet) and then multiplied by three to represent a 90-day or quarterly billing period.
Residential Customer Calculation Example 2
The example below is for a multi-family residential customer who used 350 ccf (one ccf equals 100 cubic feet), has 35 dwelling units, has 25,000 square feet of stormwater billable area, and is billed quarterly.
| Charge | Calculation | Total |
|---|---|---|
| Sanitary sewer | $12.69 x 350ccf | $4,441.50 |
| *Stormwater service unit | $35 x 0.65 = 22.75 service units (22.75 x $5.76) x 3 | $393.12 |
| **Stormwater billable area | ($13.68 x 25) x 3 | $1,026.00 |
| Total sewer and stormwater charges | $5,860.62 |
*The stormwater service unit rate is per 30 days. In the calculation above, the number of dwelling units is first multiplied by 0.65 to get the number of service units. The number of service units is multiplied by the stormwater service unit rate and then by three to represent a 90-day or quarterly billing period.
** The stormwater billable area rate is per 1,000 square feet per 30 days. In the calculation above, the rate is first multiplied by 25 (25,000 square feet) and then multiplied by three to represent a 90-day or quarterly billing period.
Non-Residential Rates
Sanitary Sewer: $13.00 per 100 cubic feet of water use
Stormwater service unit: $5.76 per service unit per 30 days
Stormwater billable area: $14.252 per 1,000 square feet of stormwater billable per 30 days
Commercial Customer Calculation Example
The example below is for a commercial customer who used 250 ccf (one ccf equals 100 cubic feet) and has 40,000 square feet of stormwater billable area.
| Charge | Calculation | Total |
|---|---|---|
| Sanitary sewer | $13.00 x 250ccf | $3,250 |
| *Stormwater service unit | 40,00 ÷ 2,400 = 16.67 service units 16.67 x $.5.76 | $96.02 |
| **Stormwater billable area | $14.252 x 40 | $570.08 |
| Total sewer and stormwater charges | $3,916.10 |
*The stormwater service unit rate for commercial customers is calculated using the square footage of impervious area, not the number of dwelling units like residential customers. In the calculation above, 40,000 square feet is first divided by 2,400 square feet to get the number of service units. The number of service units is then multiplied by the stormwater service unit rate.
** The stormwater billable area rate is per 1,000 square feet. In the calculation above, the stormwater billable area rate is multiplied by 40 (40,000 square feet).
Drainage District Customers
Over the next three years, Environmental Services will adjust stormwater rates for Drainage District customers to match rates more closely with those in the rest of the city and align with the cost of providing services.
Portland City Council directed Environmental Services to phase in rate changes for Drainage District customers over the next three years. The changes will start with 50 percent of the approved charge going into effect beginning July 1, 2024. The remaining increase will be phased in over the next two fiscal years (July 1, 2025, and July 1, 2026) until customers inside the Drainage Districts are paying the full cost of service rate as all other customers pay, adopted by City Council.
Portland Harbor Superfund Charge
The Portland Harbor Superfund charge goes towards the clean-up of Portland Harbor.
- $0.04 per 100 cubic feet of water use
- $0.237 per 1,000 square feet of impervious area per 30 days
Full List of Rates and Charges
Environmental Service has other rates, charges, and fees for service categories and user types. For a complete list of Environmental Services rates, charges, and fees, visit Environmental Services Fiscal Year 2024-2025 Rates and Charges.
How to Calculate Your Winter Average
For residential accounts billed quarterly, the winter average is calculated based on water readings between February 1 and April 30. Most water consumed is used indoors during this time of year and enters the sewer system.
Winter average volume is applied to residential accounts during billing periods outside the winter average period since much of the water used in warmer months waters lawns or gardens and doesn’t enter the sewer system.
To calculate your winter average, divide the total winter average review period consumption by the total actual days of service in your review period (days between the billed meter readings in the winter average review period) and multiply by:
- Quarterly accounts: 90
- Bi-monthly accounts: 60
- Monthly and budget billing accounts: 30
Winter Average Example
*one ccf equals 100 cubic feet of water or 748 gallons.
| Date | Reading | Consumption | Days Between Reading |
|---|---|---|---|
| 9/17/2022 | 2,172 | 14ccf* | 92 |
| 12/16/2022 | 2,184 | 13ccf* | 90 |
| 3/19/2023 | 2,195 | 12ccf* | 94 |
| 6/17/2023 | 2,208 | 13ccf* | 90 |
Winter consumption ÷ days between readings x 90 days = winter average
12ccf ÷ 94 days x 90 days = 11ccf
Minimum Use Billing
Accounts billed 0 to 2 ccf during the winter average billing period will be assigned the following winter average based on billing frequency:
- Monthly billed account: Metered winter average water use of 0 ccf will be assigned 2 ccf minimum use average per billing period.
- Bi-monthly billed accounts: Metered winter average water use of 0 to 1 ccf will be assigned 5 ccf minimum use average per billing period.
- Quarterly billed accounts: Metered winter average water use of 0 to 2 ccf will be assigned 7 ccf minimum use average per billing period. Multi-family quarterly billed accounts will be assigned 5 ccf minimum use average per dwelling unit billing period.
How Do We Determine Our Rates?
Environmental Services undergoes a financial planning process every year to determine the sanitary sewer and stormwater rates required to fund operations for the upcoming fiscal year. The final step is the Sewer and Stormwater System Rate Study.
Every dollar of your sanitary sewer and stormwater rates and charges helps fund the following:
- $0.40 - Capital Improvement Program:Capital Improvement Program projects repair or replace aging pipes and help protect people, property, and the environment.
- $0.31—Operation and Maintenance: Ongoing costs for the operations and maintenance of the pipes, ditches, culverts, sumps, maintenance holes, pollution control facilities, wastewater treatment facilities, and more.
- $0.21 - Debt Service: Debt service payments are payments for previously completed projects, such as the Big Pipe Project.
- $0.08 - Other Expenditures: Other expenditures necessary for service functions, including payments to the general fund, pension obligation bond payments, and the Portland Harbor Superfund.
Annual Rate Increase
Every year, Portland City Council votes on an annual rate increase. This vote sets rates for Environmental Services and the Portland Water Bureau. The annual rate increases allow the bureaus to raise the additional funding needed to cover the rising costs of providing services. These annual price adjustments ensure that the bureaus can operate effectively, purchase the necessary equipment and chemicals, hire staff, and invest in new projects.
Learn more about the services your Portland utility bills pay for at Beyond drinking water: Understanding your bill.
Sewer and Stormwater Rates from Previous Years
Water Bureau Rates and Charges
The Water Bureau is responsible for delivering water service to Portland residents and businesses. To learn more about the water portion of your bill, visit the water rates and charges page.