Help Diagnosing Shower Leak

Submitted by Rolltide2014 t3_10rxhlp in DIY

We’ve been in our house less than a year and just recently our first floor shower/tub started leaking a bit, dripping down to the unfinished basement.

I recaulked everything even though I couldn’t see anywhere that was obviously a problem, but it’s still leaking. It doesn’t leak when the water isn’t running, so doesn’t seem to be a leaky supply line. I haven’t noticed the leak after giving the kids a bath in there, but do while my wife showers. Given that my thought is it’s either something with the shower head connection, which I haven’t messed with at all, or it’s still some sort of caulk/leak issue that I’m missing and it’s only showing up when water’s going everywhere during a shower.

Unfortunately the holes cut in the first floor subfloor are just big enough for the supply lines (copper) and drain line (PVC) so I can’t get a great look up in there, but enough that I’m confident the water is coming from somewhere higher up and not around the floor drain.

I imagine next step should be to at least look at the showerhead right? Anything else in particular to check?

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hyperdream t1_j6yb2y7 wrote

The shower arm/pipe that comes out of the wall is usually screwed into the plumbing. You could try unscrewing it and resealing the connection with teflon tape.

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Whoooosh_1492 t1_j71x7i8 wrote

When you remove the elbow, check for corrosion.

My water is slightly acidic (pH 6.9) and it slowly eats away at shower elbows. I keep a spare around because they have a limited life span. The real trick is to replace it before it leaks and causes damage.

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RoaredTerribleRoars t1_j6yc4or wrote

I've had leaks at the tub penetrations before. Check the penetration for the showerhead, mixing valve, and spout

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RoaredTerribleRoars t1_j6ycivi wrote

Just to clarify, when I've had problems, it wasn't the connections of the pipes. It was the water running down the wall, then between the fixture and the wall. Plumbers putty/caulk for the Escutcheons Plates. Silicone caulk for the faucet

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ivykid t1_j6yqket wrote

I've worked on tubs that had tile and grout over drywall that was leaking. When I removed the tile I saw where the water had been soaking the drywall and running down below the tub.

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Rolltide2014 OP t1_j6yuejm wrote

Yeah that was my first thought too, but ours isn’t tile and grout. I honestly wasn’t sure what it was at first, as I hadn’t seen another shower/tub like this despite all the houses we looked it, but to me it just looks like “cheap crap.” After poking around, I think it’s a “glue up” shower. It feels and looks like really thin overlapping sheets of vinyl/plastic/whatever. Which does feel like that’s more seams where a leak could originate, but despite that I still think it’s plumbing related and either at the handle or further up at the shower head. I’ll plan to tear into it again tonight after putting the kids to bed.

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quadmasta t1_j6zfnzb wrote

How wet is the wall getting between the shower head and the tub?

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richardthecat t1_j6zq90b wrote

Hi, I had a leak in my shower too. I don't know if you have the same issue, but this is what I found. Because new tubs are fiberglass, they move too much. This caused the caulking at the top of the tub section to separate. Not enough to see, but just a hairline separation. Whenever I took a shower the water would get pulled into the caulk line and follow it to the edge of the tub and down the side. It was invisible. It then went behind the baseboard and leaked to the floor below. Took me a while to figure that one out.

Good luck.

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TallymanSean t1_j6y8pit wrote

Always have to eliminate human error first. Run the shower with no one in it to see if the leaking still happens.

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Pinstrip3 t1_j6ygpxa wrote

I'd take a closer look at the drain/siphon and check if the gaskets hold. Had the same issue, redid all supply pipe connections like a mad man (to no effect) just to find out it was a faulty siphon (screw holding it to the tub was too loose and I couldn't tighten it because of a broken thread).

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Rolltide2014 OP t1_j6yifd4 wrote

I’m going to be an idiot here…is the siphon the hardware on the front side of the tub above the drain and below the tub spout that prevents overflow?

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mallad t1_j6zqh6t wrote

They're talking about the trap. There are various designs, but yes the vent/overflow is a part of that which allows water to flow without creating a vacuum. It wouldn't make sense for it to be an issue if it only happens during showers.

Try running a shower with nobody in it. Does the shower head or the tub spout leak or spray some back onto the wall? If not, check the leak - it's probably dry. If it's dry, you need to check the seal around the vent/overflow, and around each handle and spout. You might need to tighten the screws a little on the vent, and caulk around it along the top half.

If the shower isn't spraying onto the wall with the handles, and you still see leaking, then you've got a leak somewhere between your tub spout and the shower head. Hopefully it's just the shower spigot in that case, because you can unscrew the entire thing, put some putty or Teflon tape on it, and screw it back in.

Another option would be to pour a bucket of water against that wall of the shower and see if that leaks. The biggest thing is just finding whether it's the plumbing leaking or the wall.

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Pinstrip3 t1_j6yqvfu wrote

Siphon is the part that prevents air from the sewage coming inside the house. Would be best if You googled it as I would have a hard time describing it in English today. Look for a shower siphon.

My grand grandma used to say "better be an idiot for five minutes than whole life". Asking questions to learn is not idiocy ;)

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DrewTea t1_j6yty23 wrote

I just finished repairs for a shower stem that broke behind the wall and leaked down into our kitchen.

Upon inspection, it looked like the pipe finally gave out after flexing with the hot/cold water. As it flexed, it was pushing against the hole in the wall (the tile and drywall) because the copper pipe from the valve was just a smidge too long. Eventually (30 years) of metal fatigue finally broke it off completely, but you could see that it had been leaking for some time - just not enough to 'notice' until it finally completely separated.

So make sure to take a good look at where the shower stem connects to the pipe behind the wall.

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MetaverseRealty t1_j6yu1n6 wrote

If it's not leaking after a bath but it is after a shower then you need to see where the water is going when running the shower. Water at the shower head, water on the walls. Even outside of the tub. If your wife is not properly using the shower liner to prevent water from spilling outside of the tub, the water could be intruding through the bathroom floor most likely where the tub meets the flooring.

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Maligannt2020 t1_j6zg48k wrote

We have a glass enclosed shower in our master, that sits on tile, had a similar problem. No issue when the rest of the family used the shower, problem when my wife did. Turned out she would let water spray from the second shower head at the shower ledge while shaving, not realizing this would drip down the glass and eventually leak outside of the shower. It wouldn't immediately drip below the shower, and by the time the water leaked down, the surrounding tile was dry. Simple fix - dont let significant water be blasted at or sit at the bottom of the glass surround.

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pollo316 t1_j6zkyao wrote

Haha actually take what I wrote here back about the drain and focus on the shower arm i thought it was the baths causing the problem not the wife's shower at first read. But the idea still helps eliminate possibilities before you go cut some holes. Fill and drain sink, toilet and tub to rule those out. You've got a drop ear at the shower.

First I would reapply plumbers tape and maybe a little pipe dope and reattach the the shower arm. If that doesn't fix it odds are the supply leak is the connect from your shower pipe to that drop ear. That will either be soldered for copper or some sort of pex fitting and you'll have to cut drywall to check.

For drain issues: Fill the tub, tint the water and drain it. Look for that color. Sounds like a waste side leak. I had this problem last year. Bad fitting going from cast iron to PVC and it broke the seal over time. Be glad it's not your kitchen ceiling like mine was.

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GentleThunder t1_j6zo2ii wrote

I had the same issue. It turns out that the o-ring in the spout was bad. Basically when you use the diverter the water leaked behind the shower since the o-ring was bad. You could try taking the spout off and see if that o-ring is still intact.

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DarkStarMorningDew t1_j6zrwgi wrote

If it’s a shower only issue, it sounds like it might be the tub spout. The diverter might not be closing fully and this could se sending the water back into the spout which could find it’s way back into the wall. I came across a product recently that’s called red disc seal or something and this might be a cheap attempt to fix the problem. My spout is kohler and it only has a set screw and it allows water to travel back down the copper pipe into the wall. I’ve been chatting with customer support a lot recently

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dannyboi965 t1_j7079pl wrote

How close is your toilet to your shower? I’ve been on a few jobs where the toilet was not caulked, the shower spray migrated under the toilet, and leaked below.

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GoingToBeBald t1_j70fwo0 wrote

In a previous home, I had a shower/ tub combo leak at the tub overflow. Even when showering, the water would bounce off of my back and run down the wall, some of it going behind the tub - inside the wall. I thought the seal around the drain was leaking, so I filled the tub and cut an access hole to finally pinpoint it.

My tub had a bad rubber gasket around the overflow drain, and a few dollar replacement part from the hardware store solved it. Hopefully you can find it soon. A leak in your house will drive you crazy!

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crowber t1_j70vrfi wrote

it could be where the showerhead arm is threaded into the pipe. This was always hard to get water tight while still at the correct angle. It could be leaking within the wall and it will only happen when the shower is going.

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