ADU conversions > Research > Estimate fees
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Source: ADU conversions > Research > Estimate fees ↗ Last modified: Sun, 19 Apr 2026 20:06:18 GMT
Building an ADU requires building permit fees, water service fees, and sometimes System Development Charges (SDCs). Some projects may qualify for SDC waivers.
Building permit fees
Permit fees ↗ are based on the type of permit, the work proposed, the valuation of the work, and the amount of staff that needs to review the work.
System Development Charges (SDCs)
New and conversion ADUs can sometimes lead to System Development Charges ↗. These are charges that help offset the impact a new project has on City systems, like roads and sewers. SDCs can add significant cost to your ADU project.
Find out more information about SDCs ↗.
ADU SDC waiver program
The City can waive SDCs for ADUs if you promise not to use the ADU as short-term rental for a period of 10 years. This promise is called a covenant. A short-term rental is a property that can be rented on less than a month-to-month basis.
You may be eligible to apply for an SDC waiver. Learn more about this program ↗.
Transportation SDCs
For ADUs where SDCs are not waived, the Bureau of Transportation charges an SDC. See the fee schedule for Transportation SDCs ↗.
Environmental Services SDCs
For ADUs where SDCs are not waived, the Bureau of Environmental Services charges an SDC. The amount of the SDC is based on any fees already paid and the current sewer connection charge.
In some cases, you'll need to change how your ADU connects to the sewer and wastewater systems. You might need to increase the size of the line, or put in a separate connection. If this happens, there will be more fees, even if we waive the SDC.
See the fee schedule for Environmental SDCs ↗.
Parks and Recreation SDCs
For ADUs where SDCs are not waived, Portland Parks and Recreation charges an SDC for the creation of any ADU. See the fee schedule for Parks and Recreation SDCs ↗.
Water Bureau SDCs
The Water Bureau doesn't automatically charge an SDC when you build an ADU. If the ADU doesn't need a change to the size of the existing water meter, then there's no charge. Find out more ↗ information about water connections.
Upon request, the Water Bureau can verify your existing water service size. If you need an increase, there will be a charge for increasing it, along with a bigger water bill in the future.
Contact the Water Bureau ↗ for more information.