We have a 4 1/2 year old house with a problem that no one has been able to figure out.
It started about 3 years ago when we began to notice a wet dirt smell in the wall behind
The shower of our bathroom. [There is a small room behind the bathroom so this wall that smells is not an exterior wall. There is a second wall also in the shower that is an exterior wall.] It does not smell all the time, frequently when you use the shower or if it is a windy day or sometimes for no reason. We stopped using the shower for a couple of weeks and the smell was still present, though not as strong. We have had two plumbing contractors come out and do the smoke test of the plumbing system and no leaks. All the plumbing vents were checked and all were in working order. We had a mold inspector out and no evidence of mold. We tore a huge hole in this wall to see if there was anything in it to cause the smell, nothing. We have tried pouring Clorox down the drains, as recommended by our water utility company. We have looked in the attic to see if there is any evidence of a roof leak, and it is bone dry. We are wondering if it might have anything to do with the drainage in the yard next to this bathroom, it is often wet for some reason, either a leak in the sprinklers or poor drainage. Or could it be due to a crack in the foundation? We do not know where to turn to next. Please Help!

You mean the pipe chase, behind your bathroom? It could be caused by dampness due to temparature changes in between rooms. You could be using hot water a lot of times, when the weather is cool, (observe) every time this happens. Try to use charcoal, it could be cheap in your area, try to buy a couple of it. Charcoal absorbs smells and sometimes moistures. Maybe it could help, only you could know. Have a nice day

We have a 4 1/2 year old house with a problem that no one has been able to figure out.
It started about 3 years ago when we began to notice a wet dirt smell in the wall behind
the shower of our bathroom. [There is a small room behind the bathroom so this wall that smells is not an exterior wall. There is a second wall also in the shower that is an exterior wall.] It does not smell all the time, frequently when you use the shower or if it is a windy day or sometimes for no reason. We stopped using the shower for a couple of weeks and the smell was still present, though not as strong. We have had two plumbing contractors come out and do the smoke test of the plumbing system and no leaks. All the plumbing vents were checked and all were in working order. We had a mold inspector out and no evidence of mold. We tore a huge hole in this wall to see if there was anything in it to cause the smell, nothing. We have tried pouring Clorox down the drains, as recommended by our water utility company. We have looked in the attic to see if there is any evidence of a roof leak, and it is bone dry. We are wondering if it might have anything to do with the drainage in the yard next to this bathroom, it is often wet for some reason, either a leak in the sprinklers or poor drainage. Or possibly could it be due to a crack in the foundation? We do not know where to turn to next. Please Help!
Is this shower on a concrete slab ? Or is it built on a wood framed floor with a basement or crawlspace below it.

Is this shower on a concrete slab ? Or is it built on a wood framed floor with a basement or crawlspace below it.
The shower is on a concrete slab.

You have water sepage through your tile and there is probably no vapor barrier behind there. If you have acces to the backside, punch an small hole to see if the floor is wet

How do you solve the problem of water sepage? I have this problem too. Please help. It smell like wet cement every time we turn on the water. I have cleaned out the drain, I have used 511 sealant on the tile and grout... nothing works .

How do you solve the problem of water sepage? I have this problem too. Please help. It smell like wet cement every time we turn on the water. I have cleaned out the drain, I have used 511 sealant on the tile and grout... nothing works

How do you solve the problem of water sepage? I have this problem too. Please help. It smell like wet cement every time we turn on the water. I have cleaned out the drain, I have used 511 sealant on the tile and grout... nothing works