Utility Sink Vent Question

Old 12-06-10, 10:40 AM
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 1
Upvotes: 0
Received 0 Upvotes on 0 Posts
Utility Sink Vent Question

I hope I'm not violating protocol by my first post being a question.
I just installed a basement utility sink, got the supply and waste lines all in place. I had to use a pump as my house's waste line is 5 ft off the floor.

I used a pro vent (indoor vent) to vent the pump chamber (the pump comes with it's own housing). But with the pro vent, the sink drains very slowly. When I remiove the vent, it drains quickly.

Here's my question: I assume it is better to vent the pump outside the house rtaher than use a pro vent. Must I vent through the roof if only a basement utility sink, or can I vent it through the side of the house, roughly 1 foot off ground level?

thanks for your help.

Old 12-06-10, 01:58 PM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 27,986
Received 2,231 Upvotes on 1,990 Posts
Pro vents are also called Studor or cheater vents and I think most codes allow the use of one in a home. It sounds like you have a chamber under the sink that contains the pump. Studor vents are basically one way valves. They let air in but do not let sewer gases out which is normally a good thing. But with a small, sealed pump chamber the water from the sink tries to enter the chamber and wants to force some air out of the chamber. The studor vent does not allow air to escape (vent) and can cause the pump chamber to slightly pressurize slowing the flow of water into it. There is probably air leaking somewhere otherwise the sink might not drain at all, or it might burp.

When the pump turns on and starts to pump water out of it's sealed chamber air wants to enter and fill the void. Now the studor vent is a good thing and opens to allow air to enter. If the vent were not there and the pipe sealed the water in the trap under the sink would probably get sucked out.

Yes, it would be better to install a proper vent to the outside. Venting up through the roof is preferred though some will allow it to go out through a side wall. If I remember correctly it cannot be below any door or window and it cannot be within 10 feet laterally (side to side) of a door or window, unless the vent is 2 feet above the door/window. Basically they don't want the wind to be able to blow sewer gases back into the house. Give your inspections department a call. They should be able to give you the correct requirements for your area.
Old 12-06-10, 02:42 PM
shacko's Avatar
Join Date: Aug 2005
Location: Baltimore County Maryland
Posts: 2,002
Upvotes: 0
Received 0 Upvotes on 0 Posts
What kind of pump do you have?, most do not allow an AAV on them, a lot of the laundry tray pumps only need a 1/2 vent hooked over the edge of the sink

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: