Information
Learn about the requirements for ADU water, sewer, and stormwater connections. When planning your utility connections, you will need to consider the trees on your sidewalk.
On this page
Connecting to City utilities
- Trees in the public right-of-way (street trees)
- Work utilities around street trees rather than removing trees.
- Removing a street tree? Learn more about tree removal and replanting.
- Work utilities around street trees rather than removing trees.
- ADU System Development Charge (SDC) Waiver. If the ADU qualifies, the SDCs for the ADU will be waived.
Water connections
Water meter options
What is it?
- A water meter on the property keeps track of how much water is used each month.
- Water Bureau will do all water work in the public right-of-way to the point of connection.
Shared meter:
- Serves both the primary structure and the ADU.
- Water bill will be shared.
- Determine the meter size. Count the total combined fixtures of the primary structure and ADU.
- What counts as a fixture? How to determine meter size? Use the Residential Water Meter Request Form.
- New service line from the main in the street to the meter (if needed). Water Bureau installation fees are your (the applicant's) responsibility.
- Serves both the primary structure and the ADU.
Separate meter:
- Serves only the ADU.
- Water bill will be separate from the primary structure's.
- Determine the meter size. Meter size is based on ADU fixtures only.
- Use the Residential Water Meter Request Form.
- Water Bureau service installation fees apply.
- Serves only the ADU.
Water supply requirements
What is it?
- The ability to shut off water.
- The size of the water line coming to the buildings depends on the fixtures.
What are you (the applicant) responsible for?
- The connection from the backside of the water meter onto the private property.
- You may need a plumbing permit.
- The connection from the backside of the water meter onto the private property.
Single supply line (if approved)
- Conversions or additions:
- Each fixture needs a shut-off valve.
- Alternatively, install a whole-dwelling shut-off valve. This must be accessible to both units.
- New construction: Each unit must have a control valve accessible to that unit.
- Conversions or additions:
Line size
- May need to increase if additional fixtures are added.
Sanitary and stormwater sewers
Connection options
What is it?
- Sanitary sewer connections depend on
- the fixtures
- the number of units
- if the property has a slope
- Sanitary sewer connections depend on
Shared connection
- 3 or more dwelling units on property. You will need a 6" sewer lateral in the right-of-way.
- Toilet limit
- Allowed if up to three toilets are on a single 3-inch line.
- New fixtures
- If the ADU floor is lower than the uphill manhole cover, a backwater valve is needed. Each new plumbing fixture must have one.
- For basement conversions:
- Fixtures above basement level cannot drain through the backwater valve for basement fixtures.
- These fixtures must connect to the sewer downstream of the basement fixtures.
- Backwater valves must stay accessible for maintenance and replacement.
- Existing conditions
- The existing sewer must follow City of Portland and Environmental Services standards.
- No "party sewers" or nonconforming connections are allowed.
- Party sewers. Two or more private sewer lateral share a connection to the public sewer.
- Call the BES Nonconforming Sewers line (503-823-7189) for questions.
Separate connection
- Requires additional permits and fees.
- Need a new connection to the public sewer? Your contractor must apply for a sewer lateral permit.
Stormwater
What is it?
- Contain and treat rainwater on the property. Do not allow rainwater to run off to other properties or the street.
- Rainwater must generally be disposed of on-site for both attached and detached ADUs.
- Contain and treat rainwater on the property. Do not allow rainwater to run off to other properties or the street.
Stormwater treatment facility
- Required if creating 500+ square feet of impervious surface.
Reference
Septic tank or cesspool decommissioning
What is it?
- Some properties have existing septic tanks or cesspools that may or may not be used.
What you need to do
- Within 10 feet of new footings and foundations
- Locate and decommission abandoned septic tanks.
- Required for additions if the house was not connected to the sewer when built.
- Locate and decommission abandoned septic tanks.
- Got a septic system? Please contact septic@portlandoregon.gov
- Within 10 feet of new footings and foundations
Questions?
- BES Nonconforming Sewers: 503-823-7189
- BES Sewer Lateral Connections: 503-823-1026
- Water Development Services: 503-823-7368Option 4