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Hi, we just moved to a new build. There is a dreadful 'sewer' smell in the house. No outside soil stack. AAV is sited behind bath panel in family bathroom upstairs. Had this replaced as plumber thought may be faulty, no change in smell. We are one of three houses and there is a joint pump station to the main sewer. There doesn't appear to be a vent on the pumping station, should there be? I have read advice and put all the plugs in downstairs sinks and covered with water to form a seal. This does seem to have stopped smell but obviously not answer to problem. Can't get builder to take notice! PLEASE can anyone advise what the problem could be.
 
Very hard to say without seeing the job is your drainage free flowing ? Any problems with toilets flushing ? Bath water emptying? Have the external drainage covers been lifted to look for blockages ?
 
Might be a design fault where the water is being sucked out of a trap somewhere,
Block overflow and put plug in one item at a time to try and isolate which it may be.
 
Very hard to say without seeing the job is your drainage free flowing ? Any problems with toilets flushing ? Bath water emptying? Have the external drainage covers been lifted to look for blockages ?
Thanks, yes drain covers have lifted and no blockage. Water/toilets drains freely and not slow.
 
Might be a design fault where the water is being sucked out of a trap somewhere,
Block overflow and put plug in one item at a time to try and isolate which it may be.
Thanks, we have plugged all sinks, opened one by one and it seems to be the kitchen sink that's the fault. That does have a small AAV attached to it since the problem started but didn't stop smell.
 
Might be a design fault where the water is being sucked out of a trap somewhere,
Block overflow and put plug in one item at a time to try and isolate which it may be.
Agreed. Then get plumber to replace the trap on that sink or washbasin with an air inlet or resealing trap. Could be a DIY job if you're handy.
 
Might be a design fault where the water is being sucked out of a trap somewhere,
Block overflow and put plug in one item at a time to try and isolate which it may be.
Hi, just to add. We didn't block the overflows but it (so far) has stopped the smell by plugging sink and leaving water in sink. Seems to be kitchen sink. Have unplugged utilities and downstairs toilet sinks.
 
Agreed. Then get plumber to replace the trap on that sink or washbasin with an air inlet or resealing trap. Could be a DIY job if you're handy.
Thank you, he did put a small AAV on under sink but that didn't stop smell. Do you think a resealing trap would do better? Also our next door neighbour has same smell in family bathroom, do you think it could be connected as they were built at same time, only months ago?
 
Very hard to say without seeing the job is your drainage free flowing ? Any problems with toilets flushing ? Bath water emptying? Have the external drainage covers been lifted to look for blockages ?
Hi, I have replied but unsure if its on here...Drains checked & water free running.
 
Might be a design fault where the water is being sucked out of a trap somewhere,
Block overflow and put plug in one item at a time to try and isolate which it may be.
Replied but not shown....New to this! Did as you said but not covered overflows. The kitchen sink seems to be culprit. Plumber did put a small AAV ON but smell continued. It has a u bend (p trap?) Should I change that to an actual trap one?
 
Agreed. Then get plumber to replace the trap on that sink or washbasin with an air inlet or resealing trap. Could be a DIY job if you're handy.
Plumber did put a small AAV on but that didn't stop smell. The u bend doesn't have a trap as such on, should I change to one with a convential trap?
 
Replied but not shown....New to this! Did as you said but not covered overflows. The kitchen sink seems to be culprit. Plumber did put a small AAV ON but smell continued. It has a u bend (p trap?) Should I change that to an actual trap one?
A (U bend) P trap IS a trap! So what do you mean by a conventional trap?

I was going to mention overflows, but you stated use of plugs had stopped the smell. So my guess in the dark is that it's something that doesn't have an overflow.

Can't you use your nose to smell the plugholes and overflows to find the source of the problem?

Failing that, if you're still stuck, pictures of your undersink plumbing might show something interesting...
 
Oddly the plug holes don't seem to smell. I meant a trap that you can unscrew at the bottom...sorry I don't know much about plumbing. But I still have kitchen plug in filled with water and no smell! Will attempt a photo! Thanks
 

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Hope this helps. Thank you for all your help.
 

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I've seen better, but I've also seen worse and I can't see a smoking gun, sorry.

You smell it from the sink itself? I'm wondering if it might not be sewer gasses, but a smell from whatever may be sitting in the pipes upstream of the trap, seeing as looks like you have 2 sinks and a washing machine (?) all on one trap.
 
I've seen better, but I've also seen worse and I can't see a smoking gun, sorry.

You smell it from the sink itself? I'm wondering if it might not be sewer gasses, but a smell from whatever may be sitting in the pipes upstream of the trap, seeing as looks like you have 2 sinks and a washing machine (?) all on one trap.
No don't smell directly from sink but smell seems to be stronger about 30ft from sink where no evident plumbing is. It's an intermittant smell and quite disgusting. We were away for a couple of days and house was terrible, had to take deep breath run in and open all doors/Windows & run all taps. It's a double sink, big & small with a dishwasher. Could it be a problem with shared pumping to main drain, just 3 houses. Next door has a smell too but in their main bathroom. Any thoughts would be welcome!
 
No don't smell directly from sink but smell seems to be stronger about 30ft from sink where no evident plumbing is. It's an intermittant smell and quite disgusting. We were away for a couple of days and house was terrible, had to take deep breath run in and open all doors/Windows & run all taps. It's a double sink, big & small with a dishwasher. Could it be a problem with shared pumping to main drain, just 3 houses. Next door has a smell too but in their main bathroom. Any thoughts would be welcome!
Drains are indeed smellier when not all houses have an open soil and vent pipe, and where lots of houses use them, but the point is that if the traps are there and working and all pipework is airtight then the foul air in the pipework should not be able to escape into the building.

30ft away and you are still blaming the sink? You must have a large house! But speaking seriously, if it's that far away, I'd be more inclined to suspect a leaking joint in the waste pipework somewhere (perhaps under the floor?) rather than a trap at 30' distance. Would recommend a plumber be called to carry out a pressure test (it's not a high pressure, but it'll tell you if there is a duff joint somewhere) of your waste plumbing (which you'd have hoped would have been done already seeing as it's a newbuild).
 
Drains are indeed smellier when not all houses have an open soil and vent pipe, and where lots of houses use them, but the point is that if the traps are there and working and all pipework is airtight then the foul air in the pipework should not be able to escape into the building.

30ft away and you are still blaming the sink? You must have a large house! But speaking seriously, if it's that far away, I'd be more inclined to suspect a leaking joint in the waste pipework somewhere (perhaps under the floor?) rather than a trap at 30' distance. Would recommend a plumber be called to carry out a pressure test (it's not a high pressure, but it'll tell you if there is a duff joint somewhere) of your waste plumbing (which you'd have hoped would have been done already seeing as it's a newbuild).
How would they find the pipe if there was a duff one? We have under floor heating and ceramic tiles. His has been very helpful thanks.
 
off the point iknow, but a socket under sink is a no no for me, if you ever get a leak. (puff)
 
off the point iknow, but a socket under sink is a no no for me, if you ever get a leak. (puff)
Thanks for the thought, will bring it up with builder....if EVER we see him. Unplugged sink and let water out after 3 days of no smell...and its back. It starts with an edgy light smell turning to intermittant disgusting one. It's so frustrating, we are not plumbers or builders and bought a new build to avoid problems. I have researched so much but feel I am going in circles. Thanks for your input.
 
grey pipe on lhs in photo, waste pipe from ? its not stale water in it thats the cause ? just a thought.
 
Thanks for the thought, will bring it up with builder....if EVER we see him. Unplugged sink and let water out after 3 days of no smell...and its back. It starts with an edgy light smell turning to intermittant disgusting one. It's so frustrating, we are not plumbers or builders and bought a new build to avoid problems. I have researched so much but feel I am going in circles. Thanks for your input.
Stand by the kitchem sink and get somebody to let a full bath water run out or flush the toilet and run the basin, use the upstairs appliances, you should be able to hear if you listen to the plug hole of the kitchen sink gurgling or bubbling. New builds shouldn't have the need for anti vac traps, it's obviously badly designed.
 
grey pipe on lhs in photo, waste pipe from ? its not stale water in it thats the cause ? just a thought.
Thanks for reply. The grey flexvpipe is the dishwasher, regularly used. Is the pipe not correct? The smell is so awful, don't think it could be just stale water but am willing to think of anything. Next door (also new built at same time) has similar problem but in main bathroom.
 
Stand by the kitchem sink and get somebody to let a full bath water run out or flush the toilet and run the basin, use the upstairs appliances, you should be able to hear if you listen to the plug hole of the kitchen sink gurgling or bubbling. New builds shouldn't have the need for anti vac traps, it's obviously badly designed.
Thanks, will try that. So if we hear gurgling in kitchen sink, does that mean that air is being drawn out of that trap? Sorry to be thick but This is so confusing....
 
grey pipe on lhs in photo, waste pipe from ? its not stale water in it thats the cause ? just a thought.
We have just heard through the grapevine that the builder intends to 'vent' the pump station tank. Do you think that is the problem?
 
Might be a design fault where the water is being sucked out of a trap somewhere,
Block overflow and put plug in one item at a time to try and isolate which it may be.
We think its coming from the kitchen sink, we did as you suggested and when unplugged kitchen sink the smell came back but its intermittent but its disgusting smell. We now have heard through the grapevine that the builder intends to put a vent onto holding tank next door. Apparently it was suggested by the Building control inspector (agent from the local council) that this may be the problem. What do you think? Any suggestion will be welcome, its really getting us down!
 
Fit a additional hepvo trap for the short term that way your sealing off from the drains worth a try. Regards kop
 
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