What is a Cesspool and How to Find it on Portland Maps

What you need to know

What is a cesspool?
A cesspool is a very large septic tank. Before city sewer was available people built huge underground cavities to hold all of the sewer and grey water from the house. The walls of the cesspool were perforated so water could escape into the surrounding soils.

What's the problem?
Cesspools average 15-20 feet deep in Portland. They were very common prior to 1950's especially on the East side of Portland. Over time they have a tendency to cave in and swallowed cars, animals and people. They can also undermine the foundation of a house causing costly repairs. 

Step 1: Is there a permit for a cesspool

  • Go to www.portlandmaps.com (only works in Portland)
  • Type in the address of the property in the top right corner of the screen and hit enter.​​​ (Use the address in the photo to follow along)


  • Scroll down on the right hand side of the screen and click on "Permits & Zoning." You should see the picture below.
  • Click on the "Permits" button.
  • Scroll down until you see the field labeled "Historic Plumbing."
  • Click on the ID 754245 for the type "Plumbing Permit" to get the photo below.
  • Looking at this permit about 2/3 of the way down beside "Other Plumbing Fixtures" it says "Change from cesspool to sewer."
  • This means there was a cesspool. Unfortunately there is no online way of looking for permits to see if it was decommissioned. 

Has the Cesspool been Decomissioned

Decommissioning a cesspool is achieved by pumping out any sewage and/or water and filling the resulting cavity with sand, gravel or concrete. That's it. 

Getting decommissioning records options:
  1. ​Go to the City of Portland, Development Services Center, Trade Permits, 1900 SW 4th Ave., First floor, Portland, OR 97201
    1. Ask them to find any records they have of decommissioning for the cesspool at the property you are concerned with. 
    2. The cost is about $15. 
    3. You will get answers and permits immediately.
  2. You can also mail a check and application to the City of Portland, Attention: Trade Permits, 1900 SW 4th Ave., Suite 5000, Portland, OR 97201.
    1. Note: It can take two weeks to get a response by mail. 

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