Odd plumbing leak

[Zachary Hoyt]

I was happy a month or so ago when I ran all the new plumbing in the house and didn't have any leaks, but today a very odd leak developed that I can't understand. It is under the upstairs toilet. There is a slow seep of clear water coming out constantly between the 3" PVC coupler and the pipe below the flange. It drips about once a minute. I dried the pipe and made sure I was seeing just where the water was coming from. It's clear that I didn't get a good glue joint on that fitting and I'll need to cut it out and replace it, but the second part that I don't understand is where the water is coming from. It seems like there shouldn't be water there except when the toilet is flushed, and then only momentarily, since the pipe is vertical. Is there something wrong inside the toilet that could allow water to be getting to the joint between the flange and the coupler and the rest of the pipe, or is capillary action somehow responsible? I'll be very grateful for any advice.

[Dick Strauss]

Check the tank to toilet seal, the water supply to tank and the toilet to flange connections. Have you checked for puddles behind the toilet under the tank? It could be that the water is coming from outside the toilet and seeping around the flange from outside the pipe. You could also have a cracked toilet. You could also have a bad seal under the toilet causing a puddle to form under the toilet when when you flush. This water then seeps around the flange and it appears as if the 3" pipe connection is bad. I'm sure I'm missing other possibilities. Good luck!

[Michael Schuch]

I always sand both mating surfaces with ~80-120grit. Then apply the primer once or twice before welding with the cement. The larger the pipe/fitting the thicker the cement you should use. For a 3" pipe I would use the thick stuff. I apply a thin coat of cement on both mating surfaces before sticking them together.

I don't see any signs of the purple primer on that connection. The primer softens the PVC making a better weld.

Sorry, I can't tell where the drip is coming from.

[Zachary Hoyt]

Thank you both for the advice. There is no water getting out upstairs, or running down the side of the coupler, so wherever the water is coming from must be internal. I'll need to pull the toilet anyway when I go up Sunday or Monday, to run the flooring under it, so I'll look into it then. I didn't sand the pipe fittings but I did use clear PVC primer and applied cement to both surfaces. I must have not done it well enough, though.

[Tom M King]

I've never sanded PVC, and must have put together over a thousand joints since I got my Plumbing license in 1975. The primer cleans the pipe good enough without sanding if you use plenty of it. While the purple doesn't look good, you can see when you have used enough of it. Swab it all around a number of times. You can see when you've cleaned good enough as it dissolves the writing on the pipe.

The water might just be what's sitting on the end of the pipe. Dripping that slowly, it would take a while for it all to come out.

[Curt Harms]

Maybe put some food coloring in the bowl and flush it. See if the drips are colored. If not, food coloring in the tank and flush that. I wouldn't think food coloring would leave a permanent stain. If neither produces colored drips I guess it'd have to be the supply tube connection.

[Maurice Mcmurry]

Almost all toilets let a little water past continuously. Most hardware stores have dye tablets that can help find the problem. Sanding is not required for PVC. Primer is important and is purple so that an inspector can see at a glance if the joints were done properly. You could fix that with a Fernco rubber fitting from underneath without taking the toilet up again.

[glenn bradley]

A lot of folks today don't bother with the twist when assembling. Agreeing that it is optimal but sometimes not possible it does spread the glue prior to the cure. I always try to twist.

[Kev Williams]

In my last house I had a leak I couldn't track down, the food coloring trick found it- the tank was micro-fractured(?) and was seeping out in several places. No idea WHY it was broken?

And our mobile home, I had to replace the sub floor in the main bathroom due to an invisible leak, which turned out to be the donut gasket between the tank and bowl. It was leaking behind the tank, down the back side of the bowl and onto the floor. Must have been doing it a long time as it went un-noticed by the old owners and inspectors when we bought it. I only found out when deciding to change out the linoleum for carpet and found soggy floor under the bowl...

[Lee Schierer]

To me it doesn't appear to be a leaky joint, it looks like drips from some other location. Show us a photo of the floor right above that leak.

[Perry Hilbert Jr]

My daughter had a toilet flapper get stuck. the constant cold well water formed condensation on the outside of the pipe and dripped constantly until she realized it wasn't shut off and handled it. Perhaps Condensation?

[Bill Dufour]

painters tape or paper towels with a rubber band will show a leak.
Something is odd. Did you use a modern ring seal with the long rubber horn? Those
should prevent any water from even touching that joint. Is the vent stack wide open. Run a garden hose down it full on.
Bill D

[Bruce Wrenn]

If you separated the bowl and tank, did you put a new tank seal back between them? Make sure floor is dry, and lay a piece of newspaper behind the toilet. Any moisture will quickly show up on paper. Turn water off to toilet, and flush it, then dry out the tank. Wait a few minutes and see if there is a leak. The flapper could be leaking into seam between tank and bowl. Once the water in the bowl has stopped filling, it shouldn't send any water down the trap, unless you have a flapper leak

[Zachary Hoyt]

Thank you all for the ideas. It's a brand new toilet which I assembled as per instructions, but the wax seal didn't have a rubber sleeve. It seemed to be working fine and was not leaking for about a month, and then this started very abruptly. There is no moisture outside on the upper floor, or on the side of the coupler, so I am sure it is not coming down the outside of the pipe from higher up. I dried the whole area with a rag and then looked closely with a flashlight and felt around to determine exactly where the water is coming out, and it's right where it is visible in the picture.

[Stephen Tashiro]

It's sometimes possible to seal leaky PVC drain joints by applying primer to them.

[Tom M King]

easiest fix is to take the toilet up, cut the top of the flange off flush with the floor or a little below, and use one of these:

https://www.amazon.com/SIOUX-CHIEF-634-124-Push-Flange/dp/B004QATQ4Q/ref=sr_1_4?crid=12QK0GO33D04F&keywords=Sioux+Chief+push+fit+stainless+ring+3%22&qid=1660944551&sprefix=sioux+chief+push+fit+stainless+ring+3+%2Ca ps%2C63&sr=8-4

I've used them, and they work fine. Just to be sure, I put some sealant around the insert after the seal is started down in the pipe. The extra sealant is probably not really necessary, but I feel better about it. I bolt the stainless flange to the floor when I can get to them like yours.

edited to add: reviews say the stainless ring is no longer available. If not, I'd use 5/16" stainless bolts as closet bolts, fastened in place on the subfloor, independent of a plastic flange. I did many like that when I was building new houses. You just want to be sure not to over-torque the nuts holding the toilet down.

[Lawrence Duckworth]

There is no moisture outside on the upper floor, or on the side of the coupler, so I am sure it is not coming down the outside of the pipe from higher up. I dried the whole area with a rag and then looked closely with a flashlight and felt around to determine exactly where the water is coming out, and it's right where it is visible in the picture.

I looked closely at the upper right corner of your coupling photo and I don't see any glue. I think it's harder to get good coverage of glue on larger diameters with the small dobbers. I like to glue the fitting and then the pipe and one more time on the fitting, give it a quarter turn when connection is being made. I'll use sand paper or a knife to deburr and smooth the saw edge of the pipe. ....I wouldn't be surprised if some of these sized fittings and pipe are out of round.:mad:

[Lawrence Duckworth]

you know if there wasn't enough glue that might explain the delayed leak. it may have held until someone got to rockin :D

[Bruce Wrenn]

I was happy a month or so ago when I ran all the new plumbing in the house and didn't have any leaks, but today a very odd leak developed that I can't understand. It is under the upstairs toilet. There is a slow seep of clear water coming out constantly between the 3" PVC coupler and the pipe below the flange. It drips about once a minute. I dried the pipe and made sure I was seeing just where the water was coming from. It's clear that I didn't get a good glue joint on that fitting and I'll need to cut it out and replace it, but the second part that I don't understand is where the water is coming from. It seems like there shouldn't be water there except when the toilet is flushed, and then only momentarily, since the pipe is vertical. Is there something wrong inside the toilet that could allow water to be getting to the joint between the flange and the coupler and the rest of the pipe, or is capillary action somehow responsible? I'll be very grateful for any advice.

Because you have access to joint, cut it out and redo it. Is that 4", or 3" pipe?

[Zachary Hoyt]

3" pipe. I did use the small in-the-can applicator, and may have failed to apply enough glue. I think I twisted the joint as I pushed it together but I am not sure. I know I did twist all of them that I could, but sometimes they weren't free to twist depending what had already been glued.

[Thomas McCurnin]

+1 to the group that sands the joint. Not required but a good practice.

+1 to the group that likes purple primer, I know my City inspector liked it.

+1 to the group that glues and twists. That is the way I was taught. It spreads the glue.

[Bill Dufour]

Glue and twist then hold for 15 seconds. On a big pipe like that hold for 30 seconds. the dabber should be at least the radius of the pipe. So for 3" use a 1.5" dabber. That means use a brush or swab or the joints will be glue starved.
Bill D

[Maurice Mcmurry]

Micro fractures in the porcelain can be a frustrating thing to track down. As mentioned above, Paper towels or toilet paper are a good leak detector.

[mike calabrese]

WARNING THE FOLLOWING IS A CRAP SHOOT (no punn intended) to eliminate your leak with a half a$$ fix

Everything mentioned above is quite good advice. If you do not want to cut into anything or start over again there is a shot you can take to try and stop the leak. If it doesn't work then you just end up right where you are now with little expense.
Get a repair coupling, cost typically about $6.00 cut it in half length then cut the half length in two halves (see sketch) with the finest kerf you can like a razor saw, dovetail saw etc. so you have approximately two 180 degree pieces from a half length of the coupling.
Dry the pipe leak best you can then coat the a larger area than the 2 coupling pieces will cover with PVC primer the purple stuff. Do the same to both halves of the coupling including the face of the coupling that you will push against the leaking fitting will . After that apply a relatively heavy coating of PVC cement to the purple areas on your pipe and coupling and place the two half pieces around the pipe with the cut lines about 90 degrees around from the leak area pushing both half pieces together and up against the bottom of the leaking fitting. Hold it there for at least 30 seconds.
It is a Rube Goldberg but if it works you are good to go as the leak is most likely an atmospheric leak and the addition of the coupling halves bonded solidly to the area may solve your problem. Good luck

484894

[Greg Funk]

Any chance the drain isn't vented properly? Does water stay in the bowl?

[Zachary Hoyt]

I cut out the leaky section on Sunday and put in a new coupler and short piece of pipe and a new (and better) flange. The old flange was plastic and had to go inside a coupler, while the new one has a stainless flange on a PVC center and goes over the pipe. I bought the plastic one because they only had one metal one that day, and I needed two, but the metal kind is better, I think. I tried to get enough glue on there and to use the cleaner enough first, so I hope it will stay suitably leak free.

I don't think venting is the problem. The toilet is wet vented by the shower at 2", and the 1.5" dry vent arm goes up from there back to the 3" main stack out the roof.

[Tom M King]

I'm sure you will never put together a leaking PVC joint again.

[George Yetka]

The primer not only cleans but mollecularly helps bond the glue to the pvc. I did a 16 story building in PVC my first day on the job I the next 10 fittings that were going in thinking I was saving time. I ended up with a couple drips on my first unit. My foreman pointed out that if I glue the joint while the primer is still wet it wont leak. After that I ran 3 apartments a day for 2 months without a drip.

[Michael Drew]

I use ABS over PVC.... So much easier to work with. Slobber glue on the pipe, as well as inside the fitting. Give it a small twist and hold.

The drip is not unusual. That water swirls all over the place with the toilet flushes. It hits the joint, then creeps through the area where the bond of melted pipe wasn't good.

[Jason Roehl]

Even better than twist and hold is to twist back and forth until you feel it start to bind. Helps to have alignment marks (Sharpie), if needed. Also, don’t play around once you start applying glue—get it on there and get the joint together. The less time exposed to air, the better.

I’ve been around plumbers who were gluing 8” PVC (air inlet for a 3M BTU condensing boiler). I’d love to see a 4” dabber! ��