Smell from toilet ONLY after heavy rain.

[seajae]

Thailand does not use "s" bends so the drains do not have a natural block for the smell, when we built the new area down stairs I made sure "s" bends were put in as I am more than aware of the stench that can come from any of the waste drains/pipes if you dont. When there is heavy rain the septic tanks can fill up with rain water and the venting pipes no longer function properly which can also cause a stench, can also mean that the toilets will not flush properly until the tank can drain

 

[Mattd]

15 minutes ago, seajae said:

Thailand does not use "s" bends so the drains do not have a natural block for the smell, when we built the new area down stairs I made sure "s" bends were put in as I am more than aware of the stench that can come from any of the waste drains/pipes if you dont. When there is heavy rain the septic tanks can fill up with rain water and the venting pipes no longer function properly which can also cause a stench, can also mean that the toilets will not flush properly until the tank can drain

 

All of the floor drains do have a P trap located where the water discharges in to the drain ring around the house, I installed these myself, not to stop smells so much as to stop mosquito's getting in, in addition they all have odor free drains fitted to them.

Understood regarding the septic tank filling up, this is what I initially thought, however, as the smell is from two independent toilet systems and both toilets flush OK even in the height of the rain, then I don't think the tanks are full to the top.

 

It could well be an atmospheric issue as suggested earlier, the question is, if that is the case, then how to stop it ? 

[bankruatsteve]

1 hour ago, Mattd said:

It could well be an atmospheric issue as suggested earlier, the question is, if that is the case, then how to stop it ? 

The same way to stop tornadoes and lightning.  

 

Actually, you could try opening windows, etc. if rain doesn't come in just to alleviate pressure changes from your house.

[Mattd]

2 minutes ago, bankruatsteve said:

The same way to stop tornadoes and lightning.  

 

Actually, you could try opening windows, etc. if rain doesn't come in just to alleviate pressure changes from your house.

I could always fit a small extractor fan in to the ceiling, which would help that and also to extract the smell.

So things to do in the coming weeks, purchase the proper wax seal rings, get the toilets lifted and the seals installed, then install extractor fans.

[lopburi3]

2 minutes ago, Mattd said:

I could always fit a small extractor fan in to the ceiling, which would help that and also to extract the smell.

So things to do in the coming weeks, purchase the proper wax seal rings, get the toilets lifted and the seals installed, then install extractor fans.

If able believe better to have a wall extractor fan in bathroom and an open type window/vent to draw air from.  Takes out humidity as well as smells and provides good airflow if positioned at ends.  

[Mattd]

34 minutes ago, lopburi3 said:

If able believe better to have a wall extractor fan in bathroom and an open type window/vent to draw air from.  Takes out humidity as well as smells and provides good airflow if positioned at ends.  

Thanks, I'll have a look at that, though it would have to be in the window I suspect, as the outside wall space is limited.

[Kinnock]

Rain displacing the air and pushing smells into the house is the root cause - but this raises three queries for me ...

 

1. Is there a separate vent to prevent pressure build up - normally some extra blue pipe that projects above the roof to allow air out?

2. Does the WC outlet fit securely in the down pipe (under the pedestal)?

3. Have they removed the cap from the small vent in the WC?  Some siphonic WC's in Thailand have small hole in the side to allow air out to prevent pressure build up.  In properly plumbed in systems with an air vent pipe projecting above the roof, this vent is not needed and it's capped, but often the roof vent is missing, so the cap can be removed from the small vent hole to allow the toilet to flush - this hole then vents smells into the house.

 

But I'd still have a look at the floor drains - I've blocked mine with a polystyrene base from a 'kratong' with the toilet brush on top of it - if there's a flood, the Kratong will float, lifting the bog brush and allowing the drain to function, but at other times it seals the drain.

[Mattd]

17 minutes ago, Kinnock said:

Rain displacing the air and pushing smells into the house is the root cause - but this raises three queries for me ...

 

1. Is there a separate vent to prevent pressure build up - normally some extra blue pipe that projects above the roof to allow air out?

2. Does the WC outlet fit securely in the down pipe (under the pedestal)?

3. Have they removed the cap from the small vent in the WC?  Some siphonic WC's in Thailand have small hole in the side to allow air out to prevent pressure build up.  In properly plumbed in systems with an air vent pipe projecting above the roof, this vent is not needed and it's capped, but often the roof vent is missing, so the cap can be removed from the small vent hole to allow the toilet to flush - this hole then vents smells into the house.

 

But I'd still have a look at the floor drains - I've blocked mine with a polystyrene base from a 'kratong' with the toilet brush on top of it - if there's a flood, the Kratong will float, lifting the bog brush and allowing the drain to function, but at other times it seals the drain.

I agree regarding the rain water displacing air, it must be this for sure, causing back pressure somehow.

 

1. Yes, there is a separate vent pipe, this is the 3rd pipe from the left in my photo on the first page of this thread.

2. This is unsure, I will purchase proper wax seal rings (if I can get them) and then re-seat both toilets, I suspect this is the most likely cause of the smell, i.e. the gas is being forced out by the rain water and some of it is managing to escape via the seal around the base of the toilets, I doubt the builders used a proper seal on the toilet to waste pipe, from comments earlier this is common in Thailand.

3. I looked behind the toilets yesterday and could not see any vent hole at all, either still sealed or open, not saying it isn't there, as it is difficult to see properly due to such a confined space and my bulk!

 

I am very confident that the smell isn't from the floor drains for several reasons, they have a water seal at the drain itself, there is a P trap on the end of the pipe where it discharges and these drain in to a completely separate grey water system that is common to the other 3 bathrooms in the house, these 3 do not have the smell and never have done.

Edited August 20, 2018 by Mattd

[lopburi3]

4 minutes ago, Mattd said:

I will purchase proper wax seal rings (if I can get them)

Cotto ships with their more expensive toilets and believe have for sale.   They are not normally used here as are made for screw tightening (where most floors are wood) and most units here are fastened with white cement on cement/tile.

[bankruatsteve]

1 minute ago, lopburi3 said:

Cotto ships with their more expensive toilets and believe have for sale. 

And the Thai plumber just throws them aside.  OP, are you planning to do this yourself?  If not, you really should find someone to agree to it before buying stuff.

[Mattd]

8 minutes ago, lopburi3 said:

Cotto ships with their more expensive toilets and believe have for sale.   They are not normally used here as are made for screw tightening (where most floors are wood) and most units here are fastened with white cement on cement/tile.

Thanks, I followed a link that a poster posted earlier to a local company producing these seals, so next chance I'll go to Boonthavorn to see if they have, otherwise I will buy toilets with them included.

Surely the seals can be screw tightened in to the floor by drilling in to the concrete and using raw bolts or similar?

 

3 minutes ago, bankruatsteve said:

And the Thai plumber just throws them aside.  OP, are you planning to do this yourself?  If not, you really should find someone to agree to it before buying stuff.

I could have a go at it myself, though I'd rather not, I am pretty sure that I can get somebody to do it properly, with a bit of coaching................. if not, then I will do it myself, how hard can it be.............

Edited August 20, 2018 by Mattd

[phetphet]

On 8/19/2018 at 4:55 AM, stud858 said:

I've had to lift two toilets up before. They weren't sealed properly at base Not only that, they weren't aligned properly.

Matching the holes and applying a good silicone glue seal fixed bad smell and improved flush.

Same here. Bad smell in two toilets, and found the drains in the floor under the toilets and the toilets themselves did not line up.

 

New seals and a lot of mastic seems to have cured the problem.  I was speaking to a builder, and he said he normally seals them with cement, as it also holds the toilet down. Must be a job to remove though.

[lopburi3]

5 minutes ago, Mattd said:

if not, then I will do it myself, how hard can it be.............

The drain hole may turn out to not be anywhere near correct distance from wall?  Toilet islands are the new style?  ? 

[lopburi3]

1 minute ago, phetphet said:

 I was speaking to a builder, and he said he normally seals them with cement, as it also holds the toilet down. Must be a job to remove though.

Normally only takes a few minutes - although I would not want to do it.  

[Kinnock]

30 minutes ago, Mattd said:

I agree regarding the rain water displacing air, it must be this for sure, causing back pressure somehow.

 

1. Yes, there is a separate vent pipe, this is the 3rd pipe from the left in my photo on the first page of this thread.

2. This is unsure, I will purchase proper wax seal rings (if I can get them) and then re-seat both toilets, I suspect this is the most likely cause of the smell, i.e. the gas is being forced out by the rain water and some of it is managing to escape via the seal around the base of the toilets, I doubt the builders used a proper seal on the toilet to waste pipe, from comments earlier this is common in Thailand.

3. I looked behind the toilets yesterday and could not see any vent hole at all, either still sealed or open, not saying it isn't there, as it is difficult to see properly due to such a confined space and my bulk!

 

I am very confident that the smell isn't from the floor drains for several reasons, they have a water seal at the drain itself, there is a P trap on the end of the pipe where it discharges and these drain in to a completely separate grey water system that is common to the other 3 bathrooms in the house, these 3 do not have the smell and never have done.

Yep - sounds like the seal to me too.  But the small vent (if you have them) is in the side of the pedestal (right hand side when seated on the throne) - only about 4 mm in diameter - and should be covered by a white clay plug.

 

Oh the glamour of ex-pat life!?

[Mattd]

11 minutes ago, lopburi3 said:

The drain hole may turn out to not be anywhere near correct distance from wall?  Toilet islands are the new style?  ? 

Yes, the distance from the wall could be an issue I think, the toilets are newish American Standard type.

 

1 minute ago, Kinnock said:

Yep - sounds like the seal to me too.  But the small vent (if you have them) is in the side of the pedestal (right hand side when seated on the throne) - only about 4 mm in diameter - and should be covered by a white clay plug.

 

Oh the glamour of ex-pat life!?

Ah, OK, when I go back home at the end of the week I'll take a look in that area, the two holes for the seal are filled with silicone, that I did see.

 

Yes, living the dream ? !!!!

[Shadychris]

Haven't bothered to read all the responses on this thread - so you may have identified the problem already. But FWIW the  'stink' pipe you have cobbled together on your 6" waste pipe is nowhere big enough to be effective. It should really be the same diameter as the foul water pipe itself. Typically the pipe coming out of the back of your loo should connect into a 'T' junction of the same bore, with one leg going down to your drain and the other up through the roof via the stink pipe. The idea being it works rather like a chimney flue with the air passing over the top of the pipe at roof level sucking the bad odours out.

With such a tiny bore pipe as you have used its not really going to do much at all...

[xtrnuno41]

Maybe it is a construction fault in the toilets. There should always be a water lock in the toilet.

Maybe you see the water is there, however not enough to work.

The toilets are properly levelled? Just a little gap can bring in the sewer air

Though you said you placed vents on the main pipe. But still with heavy rains, it seems, there is more suction

and maybe with the faulty construction of the toilets (same identical new ones) the water lock

isnt working then anymore.

That if there is no other drains in the new bathrooms.

If you have more drains in those bathrooms, they could have the (same) problem, waterlock gone

with heavy rainfall. Too much suction, despite your vent on the mainpipe.

Dont know the size of the vent pipe, 1/2, 3/4 inch?  

If the sealing wouldnt be working then you will smell at all times. But it is only with heavy rainfalls.

[Stevemercer]

As noted above, I would have thought that the extra vent pipe added to the top of the toilet outlet pipe is far too small to be effective. 

 

So is the large diameter vent from the septic tank effective? Ours sometimes gets blocked with wasps' nests and the like, and a quick hosing clears it. However, if you only get the smell during heavy rain it might be that the septic vent pipe extends too far into the septic and gets covered during a temporary rise in level due to rainwater (which recedes after 10 or 15 hours assuming the septic system is 'open' at the bottom to allow drainage into the earth).

 

The above is not an easy fix, and it might be better to seal the toilets anyway.

 

 

[keithcresswell]

I had exactly the same problem. It took me years to realise that the very back of the toilet (out of sight) had not been completely cemented in.

[rwill]

I prefer the floor drains with the weighted flap that closes when no water is draining.  Keeps out odors and critters.

 

 

[Formaleins]

I expect you are using the 4" plastic piping for the toilet drain. Immediately after it exits the bathroom to the outside you should fit one of those 4" pipes with the 3/4" or 1"  T connector, then connect a suitable pipe that raises it up your outside wall to near the roof area. This will vent any gases away from the house. If you look at the way Brits used to have their plumbing in the '60's and ' 70's you can usually see the ugly 4" pipe that goes outside the house all the way up to the roof, and often through and above it that was used as a vent before the planners put in regs. to make sure it was concealed.

 

One more thing to check is that when the toilets were fitted, make sure that they fitted a wax gasket or similar - We had four toilets put in when I was building this place and three had the gaskets and one did not - they simply went around the outside of the base of the toilet and sealed it with grout. This does not work, you will get smells and eventually some seepage.

[lopburi3]

1 hour ago, rwill said:

I prefer the floor drains with the weighted flap that closes when no water is draining.  Keeps out odors and critters.

 

 

Weighted type closures are noted as being very unreliable and build up of crud quickly destroys any good seal.  U or S bend type drains full of water are much more reliable IMHO.

[Mattd]

Thanks for all of the replies, they have given me some options to explore to try to resolve this.

Regarding the extra vent that I put in, I agree it is small, but it is an extra vent, the main vent from the septic tank is a 1" pipe, the extra one was a test to see if it helped at all, it doesn't ? 

[55Jay]

Not related to toilet odor, but I just saw this on a Facebook page this morning and thought I would share it here.   Seems like a low cost work-around for existing houses without p-traps on floor drains.  ?

 

https://www.lazada.co.th/-i225824365-s345204296.html?spm=a2o7g.10605368.0.0.faab1e13yu7Gta&urlFlag=true&mp=2

 

 

[55Jay]

2 hours ago, 55Jay said:

Not related to toilet odor, but I just saw this on a Facebook page this morning and thought I would share it here.   Seems like a low cost work-around for existing houses without p-traps on floor drains.  ?

 

https://www.lazada.co.th/-i225824365-s345204296.html?spm=a2o7g.10605368.0.0.faab1e13yu7Gta&urlFlag=true&mp=2

 

 

Hadn't noticed, this was posted above already.  ?

[sometimewoodworker]

On 8/19/2018 at 8:09 PM, Esso49 said:

On 8/19/2018 at 3:51 PM, lopburi3 said:

He said they were brand new - and if working right (you are not adding something to kill bacteria) should seldom, if ever,  require any pumping out.

Utter rubbish , most Septic tanks in Thailand are not even 2 stage let alone 3  and best practice here , as in  the UK, is that they recommend a septic tank should be emptied once a year (As a general rule of thumb, it's recommended that you have your septic tank emptied roughly once a year, although if you live alone or in a very small household, you may get away with having your septic tank emptied bi-annually if, for some reason, you can't get around to having yourtank professionally emptied. )

You are  referencing something completely different to the normal septic tank as used in Thailand as the vast majority of septic tanks do not discharge to surface water. You should at least get the correct link.

 

Also so the U.K. Guidance is, to say the least, way more than is needed.

 

My brother's septic tank had to be rebuilt after 30 years but even then it had more than enough sludge capacity to have lasted another 30 years, it had never been de-sludged in that time. My Thai septic tank is over 15 years old and has never been de-sludged or pumped

[Shadychris]

6 hours ago, Mattd said:

Thanks for all of the replies, they have given me some options to explore to try to resolve this.

Regarding the extra vent that I put in, I agree it is small, but it is an extra vent, the main vent from the septic tank is a 1" pipe, the extra one was a test to see if it helped at all, it doesn't ? 

It wont help as per my previous reply - it is way too small a diameter to be effective as a stink pipe. If your septic tank vent is also only 1", then yet again that is much too small to be of any real benefit. However as you say the problem only affects one bathroom then its unlikely the problem lies with the tank - but is specific to the arrangement in that room. Start by ripping that 90% bend off and fitting a T connector so at least you know you have a properly efficient stink pipe. Not that big a job to do.

[Esso49]

Just following up.    Have you found the cause yet and/or rectified it ?

[sometimewoodworker]

On 8/21/2018 at 3:34 PM, Shadychris said:

If your septic tank vent is also only 1", then yet again that is much too small to be of any real benefit.

If the waste system is correctly vented then a 1" septic tank vent is easily big enough as it is just venting Gas built up by bacteria detesting the waste products. In fact depending on the design of the plumbing, assuming it is correctly vented you may not need to vent the septic tank at all