Building Official Determination 17-01: Shared Drywells

Building Code Guides (BCGs) and Building Official Determinations (BODs) provide answers about the application of building codes and outline optional alternates. BODs are typically smaller in scope and address simpler questions. Code Guides provide a comprehensive alternative to a complicated set of code requirements.

BOD 17-01: Shared Drywells  

QUESTION: When a drywell is an approved method of stormwater management, can one or more lots share a drywell?

RESPONSE: The Oregon Plumbing Specialty Code (OPSC) Chapter 3, states that no drainage system can be located on any lot other than the lot that is the site of the building, structure, or premises served by such facilities.  The City of Portland has determined that drywells can be located on a different lot than the lot with the building, structure, or premises served by the drywell without a plumbing code appeal if ALL the following conditions are met:

1. The drywell must be allowed as a method of stormwater management as approved by the Bureau of Environmental Services (BES).
2. The drywell serves the buildings, structures, or premises on which it is located, in addition to other buildings, structures or premises located on a different lot or lots.
3. In situations where the City of Portland Stormwater Management Manual applies, an operations and maintenance agreement is required and must be recorded with the appropriate county recorder.  The agreement must include a description of the operation and maintenance, log sheets of proposed operation and maintenance, and infiltration testing results.  The operations and maintenance agreement must be reviewed and approved by BES prior to recording.
4. An easement and maintenance agreement for the shared use of the drywell is required and must be recorded with the appropriate county recorder. The easement and maintenance agreement must be reviewed and approved by prior to recording.

Alternative proposals not meeting the standards of this BOD may be approved on a case-by-case basis through the administrative appeals process.

HISTORY: Implemented June 6, 2017. Revised May 30, 2024.

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