Building Official Determination 16-01: Simplex Pumps

QUESTION: Can a single pump system (simplex pump) be used in the sewage ejector system in a commercial building when plumbing fixtures cannot be drained by gravity?

RESPONSE: The City of Portland has determined that when plumbing fixtures cannot be drained by gravity in commercial buildings, the use of simplex pumps will be allowed subject to the following: 

1. Each simplex pump may be used to serve one the following options: 
   1. A maximum three bathroom plumbing fixtures (water closet, lavatory, urinal or shower/tub)
   2. A maximum of one laundry tub, two floor drains, two trench drains, and two floor sinks
   3. One clothes washer
   4. A maximum of two sinks in a commercial kitchen.
2. Simplex pumps are allowed under all of the following conditions:
   1. More than one simplex pump is allowed in a building. 
   2. Each simplex pump must have an individual sub-drain with a sewage ejector pump to a gravity drain. Per BES regulations, the pressure line must transition to a gravity line before entering the public right-of-way.
   3. The sizing of the simplex pump and sewage ejector required is per OPSC 710.3.

Other alternatives may be reviewed and considered on a case-by-case basis through the administrative appeals process.

HISTORY: Implemented May 16, 2016. Revised May 30, 2024.

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