I recently purchased a home built 40 years ago. It was owner built, who was not a contractor. The home 1800 sq ft top level and 1300 sq ft finished basement. There are no sewer vents. Toilets have low water levels and plumbing gurgles and glugs. The finished basement has a toilet, laundry, shower bath sink and kitchen sink. The only vent is in the bath sink inside the cabinet.

Upstairs - Bathtub, shower, two toilets, two bath sinks and kitchen sink again no vents. Nothing is going through the roof. I am replacing the shower stall in the master. If I vent the shower will this help anything or not? The shower P-trap keeps water about 3 inches above the top of the p-trap. Can I vent off the 2 inch waste line coming from the Laundry, kitchen and then shower and ends up going into a vertical drain line that flows into a septic tank.

All 3 toilets have low water levels and glug. The shower and occasionally toilet will glug when washing clothes downstairs or taking a shower.

  • 1
    Your location matters. It does seem like the builder goofed up big time, but check the attic if possible. The symptoms do point a blocked/lack of vent/s.
    – crip659
    Mar 15, 2023 at 19:55
  • 2
    You might be a candidate for the Point-of-use vents
    – Traveler
    Mar 15, 2023 at 20:21
  • Are you required to get a permit for plumbing work in your area? If so, meeting code and getting the inspector to sign off on the work seems to be a benefit.
    – spuck
    Mar 15, 2023 at 21:45

2 Answers 2


Any venting will help. At a minimum it'll help local fixtures drain more readily, but it may provide some relief to fixtures in nearby areas as well. There's virtually no risk in doing so.


For situation like yours there is help.

You do not need to rip open the walls nor drill holes in the roof.

Referred as "Point-of use Vents aka AAV- Air Admittance Valve for a Sink

Those devices can be installed under the sinks and will hep venting the drains.

Since all the drain pipes are connected together somewhere, venting will help. If you can vent the shower then do so.

Example of installation:


  • 3
    An "air admittance valve" is not a vent. The purpose of venting, according to the Uniform Plumbing Code, is to protect the traps against siphonage and back-pressure, and so that air circulation is assured throughout all parts of the drainage system. AAV's only address the siphonage, and AFAIK are not allowed everywhere.
    – kreemoweet
    Mar 16, 2023 at 3:49
  • 1
    They aren't legal everywhere: https://www.answerthehome.com/what-states-allow-air-admittance-valves/ Mar 16, 2023 at 5:00

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