You are here:

Plumbing in the Home/big air pocket at end of flush


I have a concrete floor. At the end of the flush a big air pocket comes up in toilet. It is a 24x24 building in the country and I did the plumbing myself. It has one bathroom and kitchen sink. I have been using this plumbing for six years without any problems. I did not put a vent pipe in because I plain forgot about it. Could I put a vent pipe outside on my 4" waste line?

Hi hal,
You could try, it might help.  Without a vent the drainage flow slows down due to a vacuum being generated and is more likely to deposit out the solids inside the pipe rather than flush them all the way to the end into a septic or sewer system.  The standard is that the total sq in of venting should be equal to the sq in of the waste.  So a 4" waste line would require a 4" vent.

I'm not sure how effective an "after thought" vent is going to be but it's got to be better than no vent.

Good Luck

Plumbing in the Home

All Answers

Answers by Expert:

Ask Experts


Dana Bostick


Pretty much any residential plumbing questions. For "item specific" details such as a specific model of fixture, I will need to research and there may not be any useful information available. Note: I live and work in Southern California. We do not, as a rule, use hot water or steam heating systems, oil fired boilers or private water wells so my knowledge in those areas is pretty limited. There are others here on AllExerts that can probably answer those questions better.


Retired, Licensed General Contractor with Plumbing license. Active Home Inspector, Litigation Consultant and Infrared Thermographer, Online Marketing specialist.

Publications "Rain Maker" as "Inspector Dana", about making money online.

30+ years in the building trades, Licensed General Contractor (Retired), Certified Infrared Thermographer Internet Entrepreneur, Amazon & eBay Merchant (deals-by-dana)

Awards and Honors
Listed FHA Fee Inspector, FHA 203(k)Consultant, HUD Mobile Home Inspector

Past/Present Clients
Home buyers, sellers and owners, Investors, Commercial roofing companies (infrared roof scans for moisture intrusion, Litigation Consulting for "Slumlord" laws in SoCal

©2016 All rights reserved.