Drain To Vent

[dav-az]

Hello all, I need a little advice. The firm that installed my soft water system ran the drain line into my garage deep sink vent stack up in the attic. Seemed OK to me at the time. I am now concerned that sewer gases could potentially be making their way into the water system. Is my concern valid? Should I reroute the drain? Thanks in advance for any info provided.

[ion_avenger]

The installation that you describe is called "wet venting" and is allowed in many localities. I called a friend who works the Phoenix,AZ area and he says they wet vent often.

Wet venting is mostly not a problem with softener installations, but you MUST put a p-trap inline between your softener drain and the vent that you're draining to. Also, the softener drain should be air-gapped. Those two steps will provide protection from cross-contamination and eliminate sewer gas from coming into the room.

[dav-az]

Ion, Thank you very much for the reply and for calling your contact. I do appreciate it. There is no p-trap. I'll have to figure out a way to put one in on a 3/4 " line. The vent is in the attic so I don't think an air gap is an issue as the sink it works with is some ten feet down. Am I thinking correctly here?

[ion_avenger]

Code is pretty clear on the air-gap. As a licensed contractor I can't tell you to go against code,but I have seen installs done where the installer doesn't put in the air-gap and just put a spring check on the 1/2" softener drain line.:)

[dav-az]

Well I certainly don't have a problem with air gaps but what I'm working with right now is a 3/4" line sticking down the end of an open vent. To create an air gap what do I need to do, suspend the end of the line above the top of the vent pipe? Perhaps I can rig some kind of funnel on the vent and strap the drain line above it. Too bad the firm I paid to do the work didn't do it correctly.

Anyway, thanks much for your help and advice.

[ion_avenger]

That's exactly how they do it

Enlarge the vent pipe up to 4" (something like this http://secure2.data-comm.com/servlet/RBIS/-strse-28082/Pipe-Reducer-4-x/Detail ) , and then suspend the drain line above it.

[Clay-Yell4George]

The way to tie into a vent would be to cut in a drain tee the size of the vent. Once the tee is insatalled on the vertical section of vent you can glue a p-trap into the branch of the tee. Again the p-trap is the same size as yhe vent pipe. Once your p-tarp is glued in place purchase an air gap fitting (airgap.com look at Mr. Drain) . This will then allow you to be able to hard pipe the drain instead of trying to suspend the drain above the p-trap.

[dav-az]

Well this project just got a little more interesting. I'll have to see what my local plumbing supply guys have in stock. Thanks again for the help both of you. I'll definately feel better knowing this is corrected.