Septic Tanks - Bathroom Smell

[Wentworth]

My builder has installed 3 of the round concrete septic tanks for each of my bathrooms. There's also a metal disk fitted for access. Inside the bathrooms it smells like a sewer and they have temporarily put a breather pipe, but it still smells. I've tried putting the bio powder but still no difference. My wife was told that there have to be breather pipes, but I haven't had this before in my previous house using the same system and I don't see anyone else using them. I get the feeling that there's something wrong with the installation and also that my builder is waffling to my wife.

[NeverSure]

Of course you have to have p traps even under toilets. I don't know what they are called in all Western countries, but they are the U shaped pipe which holds water and stops gases from coming into the room. They are easy to see under sinks. Toilets have those too. You may not. ??

Every drain must have a vent, even if it's a vent shared with other drains. With no vent, the water will siphon right out of the p trap, and you will get gases from the sewer in the room.

http://en.wikipedia.org/wiki/Trap_%28plumbing%29#Venting_and_auxiliary_devices

Edited December 11, 2012 by NeverSure

[theslime]

Of course you have to have p traps even under toilets. I don't know what they are called in all Western countries, but they are the U shaped pipe which holds water and stops gases from coming into the room. They are easy to see under sinks. Toilets have those too. You may not. ??

Every drain must have a vent, even if it's a vent shared with other drains. With no vent, the water will siphon right out of the p trap, and you will get gases from the sewer in the room.

http://en.wikipedia....xiliary_devices

have to agree also. Usually the toilet bowl has an s trap and the water that you see stops smell. Vent as close to the high side before the S trap

[alfieconn]

If you didn't have a breather pipe then you would have even more of a smell in your rooms ! as the breather pipe is to let all the bad gases out.

Any pipes running from the septic tanks have to have "u'' bends to stop smells coming back into the room, all toiles and sinks generally have "u" bends so its probaly coming from any floor drains you have in the room.

[theslime]

If you didn't have a breather pipe then you would have even more of a smell in your rooms ! as the breather pipe is to let all the bad gases out.

Any pipes running from the septic tanks have to have "u'' bends to stop smells coming back into the room, all toiles and sinks generally have "u" bends so its probaly coming from any floor drains you have in the room.

Easy to check. when you drain water from sink can you hear it dripping inside pipe, as it runs to waste, if it sort of echoes then you have no s or p trap

[Wentworth]

Grateful for the help. I'm on board about the breather pipe, though they are the standard 2cm blue pipes sticking up about 6 metres. I wonder if the pipe needs to be wider and perhaps not so high off the ground. If that's not it then my guess is the 'U Bend' under the toilet. The builders are seasoned pros and so I just took it as read that they would do it automatically; presuming that's where the problem lies. The Architect has finally realised he needs to do a site visit and I'll get my wife to tactfully chat to him about it.

[Crossy]

Probably not the toilet unless it's really badly installed, most (all I think) toilets have the trap built in to the porcelain so no need for one in the soil pipe too.

I'll put money on it being a floor drain, many builders use drain inlets with a tiny amount of water that's intended to act as a trap, install slightly off level and it doesn't work and even if it's perfect the water evaporates and lets the smell in.

Place a saucer upside down over the floor drain and see if the smell improves, verify that all sinks have U traps.

Our soil stack (the big pipe from the loo) has a 2" vent pipe from the highest point to just below the roof.

[kamalabob2]

Another possible cause of the problem is the builder cutting a corner and not running a separate pipe for the urinal or toilet to the septic tank. He might have tied in a shower floor drain into that pipe. We had the "best of both worlds", (joined pipes that should not have been joined) AND (no "U" trap under the shower drain). If I had gone under the house years ago I would have spotted this flaw, but it was recently fixed by our local builders merchant staff. Unless you bought some weird toilet any modern flushing toilet in Thailand has a built in "trap" in the porcelain as Crossy stated. See the photo of 2 problems in one pipe that I've attached. We now have proper separate pipes going to the respective places, only the urinal goes to the septic tank. The shower drain now has a "U" trap, which has an opening at the bottom to drain out hair from the "U" trap under the house.

[NeverSure]

Grateful for the help. I'm on board about the breather pipe, though they are the standard 2cm blue pipes sticking up about 6 metres. I wonder if the pipe needs to be wider and perhaps not so high off the ground. If that's not it then my guess is the 'U Bend' under the toilet. The builders are seasoned pros and so I just took it as read that they would do it automatically; presuming that's where the problem lies. The Architect has finally realised he needs to do a site visit and I'll get my wife to tactfully chat to him about it.

Because (I believe) Thai toilets are made in LOS, I'm not sure, but everyone here says they have the p trap built into them just as those I've seen in the US, Canada and W. Europe. If there's water in the bowl after you flush, you have a seal against odor. So, you're good there.

I'm on board with the two ideas expressed here. Either you don't have a proper vent and the water is siphoning out of a p trap, or you don't have a p trap somewhere such as under the shower drain. No, the vent stacks don't remove the odor. They break the siphon when water goes down the drain so that water can stay in the p traps as a seal. There is always water in those p traps even when flushing/draining as it always seeks that level.

Does the shower drain have a removable disc or square that is perforated to catch hair, etc., and to make the floor smooth to walk on? Does it remove with screws? If so, you could remove it and look down for water standing in a trap. You could also use a wire and fish down in there and probably feel whether there is a p trap.

Good luck and I hope it isn't all in concrete.

Edited December 11, 2012 by NeverSure

[canuckamuck]

I have the same issue, and it is the floor drains for sure. They have a built in flapper valve to stop gas escaping, but they aren't staying closed. we put plastic pots over them in the night time and the smell stays away. But I guess I should look into whether I can bodge a vent pipe in.

[MichaelJohn]

I had exactly the same problem.

We have 3 "tanks"; made from concrete cylinders and sunk in the ground, one is for the kitchen sink, one is for the bathroom wash basins/shower (from 2 bathrooms) and the third is for both toilets.

We had BAD smells :-( but not from the toilet tank. I was surpised that what was effectively clean water (water with soap in) from the sink/basins/showers could generate such a smell; but it does.

Both the kitchen sink and the bathroom basin/shower had no P traps/U bends - which I think is Thai standard? So, I made a U bend from 4 x 90 Deg bends and put it on the pipe outlet inside the tank. This stops any gas from within the tank coming back up the pipe and up through the sink/basin/shower drain. Worked a treat and the smell went instantly. Much easier than installing Ubends on every sink/basin/shower and I'm not concerned about blockages in these U bends as it's 2" and there's only soapy water going down.

Incidentally the Thai toilets all have traps within the procelain, hence why there's water in the bowl to stop the gas. However, the usual outlet from a Thai toilet is straight down through a hole in the floor to the blue pipe and they usually don't seal this joint hence a smell can leak from here and then from the joint where the toilet meets the floor tiles. It's worth making sure that either the toilet is sealed to the blue pipe (if you like to remove the toilet) or just silicone the toilet to the tiles.

Good luck.

[ksamuiguy]

Take up the toilet and see if the pipe is under the toilet opening, there should also be a wax ring seal sealing the pipe to the toilet.

Builders fail to take the tile thikness into concideration when installing the toilet soil pipe.

If the floor drain pipe goes to the septic tank directly it is usually easiest to put the P trap in the pipe at/before the tank.

If you need to put a vent in the tank remember to put a T fitting on the top of the pipe, it will help stop wind from going down the pipe in to the tank.

better yet Add a pipe about 30 cm long that has been filled with Charcoal, cheep is Ok aquarium grade, (not cooking charcoal) this can be fitted over the vent pipe it will absorbe 90% of the odor that comes from the vent pipe, use the aquarion fiber filter material in each end of the charcoal pipe, plastic misquito netting to keep in place at the bottom.

[JAS21]

Yes had the smell problem. We found that there was a hole in the floor, about the size of a coin, beneath the toilet. Put your hand around the back of the toilet and inside the support. If you feel a hole cover it. Actually it may have been covered initially but now it isn't. That's what happened to two of our toilets... all of a sudden a terrible smell.

Actually have to admit that we were stumped at first but one of the guys who worked for the builder but now works in our village pointed us in that direction.

[TongueThaied]

Of course you have to have p traps even under toilets. I don't know what they are called in all Western countries, but they are the U shaped pipe which holds water and stops gases from coming into the room. They are easy to see under sinks. Toilets have those too. You may not. ??

Every drain must have a vent, even if it's a vent shared with other drains. With no vent, the water will siphon right out of the p trap, and you will get gases from the sewer in the room.

http://en.wikipedia....xiliary_devices

I lived in a house here that had no stink in the bathroom. Then we had the tile floor replaced, which required toilet to be removed and the old floor to be broken out with sledge hammers. After they finished, the tile work was beautiful, but the bathroom had a sewer stench that made you want to retch if you got a good whiff. The toilet had water standing it in, as it should, so the stink could not be coming from there. The stink was coming from the floor drain which drained to the out of doors, so it was a mystery. I was pouring bleach down the floor drain for a brief respite from the stink.

Finally I had all I could take and launched a serious investigation. What had happened is that somehow, they had knocked a hole through the drain pipe from the floor drain in the concrete. I discovered it by probing with a wire and found the hole. The drain pipe was routed through the septic and out into the yard. The hole was knocked in where it went through the septic so the sewer gasses were going into the drain pipe and into the room. It was a mess because the broken pipe was under the new floor making access for repair impossible, and the workers that did it denied all responsibility -- even got angry. We eventually moved.

By the way, and oddly, the septic tank was under the bathroom floor, which is why the drain pipe ran through it. the septic had a lateral pipe that angled up to the outside outside that allowed it to be pumped.

Edited December 12, 2012 by TongueThaied

[David006]

Take up the toilet and see if the pipe is under the toilet opening, there should also be a wax ring seal sealing the pipe to the toilet.

Builders fail to take the tile thikness into concideration when installing the toilet soil pipe.

If the floor drain pipe goes to the septic tank directly it is usually easiest to put the P trap in the pipe at/before the tank.

If you need to put a vent in the tank remember to put a T fitting on the top of the pipe, it will help stop wind from going down the pipe in to the tank.

better yet Add a pipe about 30 cm long that has been filled with Charcoal, cheep is Ok aquarium grade, (not cooking charcoal) this can be fitted over the vent pipe it will absorbe 90% of the odor that comes from the vent pipe, use the aquarion fiber filter material in each end of the charcoal pipe, plastic misquito netting to keep in place at the bottom.

While P traps on sinks are certainly good to prevent smells, it is not so easy with shower drains due to access problems (ie in a slab) which would be a pain if you ever have a blockage ( just had to de-rice/veggies and hair etc from our our common grey water pipes using a shop vac).

Occasionally have drain smell in upstairs bathroom ( strangely never downstairs which is essentially slab) from shower drains ( no p traps or vents) .....usually throw down some bowl cleaner or bleach.

Since our grey water goes out direct ( no tank) downhill among the brush/trees , think that the wind somehow causes it or accumulated slime in the pipe?

As stated, flush toilets have a built in trap, access/installation of a trap is impractical in many cases...I installed two capped clean out points outside en route to the septic tank though.

Our plastic septic tank vent is actually horizontal next to overflow and about 50 metres long out away from house and seems to be effective. (initially had an ugly tall vertical but some odour pervaded our upstairs nevertheless)

It would be nice if one could have found radial curved joints and tees in smaller diameters like sewer and conduit?

The joints, I suspect, always leave a ridge of adhesive inside or a gap which must give a potential footing for accumulation of crap?

Someone mentioned wax toilet seals..could not find 'em here so brought 'em from overseas.