Help finding a leak in DWV inside the wall or ceiling.


Old 09-29-11, 09:20 PM
Thread Starter
Join Date: Jul 2011
Location: United States
Posts: 7
Received 0 Votes on 0 Posts
Help finding a leak in DWV inside the wall or ceiling.

We detected water entering the basement from above the first floor subfloor which we believe is coming from a leaking PVC standpipe. We find the water right where the standbipe passes through the subfloor while in the basement. If we run water in any first floor fixtures we do not get 'more' water. If we flush any of the 2 second floor toilets we detect more water. We did this by adding a heavy dose of chlorine bleach to the toilet tanks and flushing them. The water in the basement had a strong chlorine smell. (By the way, this is a recent purchase of a house that has been vacant for several months.

So the leak is above the first floor subfloor, but before the '1st' second floor toilet. Short of ripping out the sheet rock between the first floor and ceiling to expose the entire standpipe, and perhaps even the ceiling of the first floor up to the toilet, until we find the leaking spot, does anyone have any clever tricks to help us isolate where along the pipe the leak may be without x-ray vision?

I wold like to keep the drywall patching to the smallest area by homing in right on the leak.

I don't think the leak is at or near the toilets since there are no stains in the ceiling. That leaves the tee where the drain pipe turns down through an interior wall. The other possibility is that the previous owner drove a nail or screw through the wall and into the pipe to hang a picture; then removed it when they prepared the house for sale.
Sponsored Links
Old 09-30-11, 03:06 PM
Forum Topic Moderator
Join Date: Sep 2005
Location: USA
Posts: 4,646
Received 19 Votes on 18 Posts
The problem with leaks is that they tend to follow the piping or joists, so often though it seems the leak is coming from one point, it could be far 'upstream'. I know, that's totally unhelpful

Unfortunately, I think some drywall's going to have to come out. Sometimes though, it's easier to take out a large square (that can be replaced afterward) rather than trying to skimp and only take out 12" squares at a time.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

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