Sewage Stink

missgeorge

Our extension was built over the sewage drain of the house in the 1970s. The previous owners put a wooden floor and lino over it. When I discovered this, I tiled had a floor trap door installed so that we can access the drain for blockages - thankfully there hasn't been one. But for months now we intermittently get a foul sewage smell in our utility room where the trap is - it's worse in the evenings and sometimes it's not there at all. Is there a broken seal or trap? Is there a deodorising fluid I can pour down our drains? What's causing the smell? Moving the drain back out down the garden isn't an option financially. Any advice as to why this is suddenly stinking and what I can do about it much appreciated.

the_pen_turner

it is caused by blockages down the line either direction. the smell usually escapes through a vent but that escape is blocked and your man hole is its next easiest way out.

get the council to clean the sewer. there is probably a build up in the pipes.

seal up the man hole with silicone (cheap stuff or you wont be able to open it ever again )

or install a vent from the man hole outside. probably expensive

Gumbo

the_pen_turner wrote: »

it is caused by blockages down the line either direction. the smell usually escapes through a vent but that escape is blocked and your man hole is its next easiest way out.

get the council to clean the sewer. there is probably a build up in the pipes.

seal up the man hole with silicone (cheap stuff or you wont be able to open it ever again )

or install a vent from the man hole outside. probably expensive

The council will not clean the sewer. It's a private system and it must be maintained by all users of that system.

the_pen_turner

Sorry I thought it was a public system.

That makes it easier.
Go to whoever is in charge of it and organise to have the system jetted. .if it's a group system then there are changes that should cover this

missgeorge

Thanks for the replies. It is a public system - not sure if the stink is back up from the pipes that are on the council's maps. I suspect it's a blockage further down the system - baby wipes or a fat berg. If people along the street pour white spirits down their drain, I can smell it in our utility room. The blockage could be in any one of their pipes leading into the shared sewage pipe that runs behind our houses. Not to be holier than thou - but we never put anything dodgy down the toilet or drain because we're so conscious of having the drain inside the house. The confusing part is how intermittent the smell is - it can vanish for 48 hours and then come back with a vengeance and then slowly disappear again. Surely a blockage doesn't come and go?

missgeorge

The manhole is about 18 inches inside the back door of the house, that leads out to steps down to the garden, any idea what installing a vent there would involve or cost?

missgeorge

the_pen_turner wrote: »

it is caused by blockages down the line either direction. the smell usually escapes through a vent but that escape is blocked and your man hole is its next easiest way out.

get the council to clean the sewer. there is probably a build up in the pipes.

seal up the man hole with silicone (cheap stuff or you wont be able to open it ever again )

or install a vent from the man hole outside. probably expensive

The manhole is about 18 inches inside the back door of the house, that leads out to steps down to the garden, any idea what installing a vent there would involve or cost?

the_pen_turner

hole deep is the pipe below the floor and outside

missgeorge

the_pen_turner wrote: »

hole deep is the pipe below the floor and outside

A couple of feet it runs under three steps down to garden level

the_pen_turner

have you got a few spare times for the floor.

you could potentially take out the top step or 2 and drill in with a 50mm bit and vent the manhole with waste pipe

missgeorge

the_pen_turner wrote: »

have you got a few spare times for the floor.

you could potentially take out the top step or 2 and drill in with a 50mm bit and vent the manhole with waste pipe

Would be great if that worked! Have spare tiles, alright. Is this a job for a general builder/plumber/drains company? Don't know where to start TBH

the_pen_turner

probably a general builder. they will put the steps back etc.

missgeorge

the_pen_turner wrote: »

probably a general builder. they will put the steps back etc.

Thanks for the suggestion. Will give the silicon a go as a short term solution and then look into having a vent installed. Now does anyone want to help draft a letter that won't p**s off my neighbours, asking them to stop putting dog poo, wipes and grease down their drains??? ;-)

the_pen_turner

i think that is something for whoever is over the sewerage to send. i dont think it would be well received from a neighbour.
people dont care about it once it is flushed away

Skatedude

Honestly, start with just duck taping the man hole cover and see if it makes any difference, not a fix, but will help confirm that the fumes are definitely coming from there

missgeorge

Skatedude wrote: »

Honestly, start with just duck taping the man hole cover and see if it makes any difference, not a fix, but will help confirm that the fumes are definitely coming from there

Have just done that right now. Good idea.

Gumbo

the_pen_turner wrote: »

Sorry I thought it was a public system.

That makes it easier.
Go to whoever is in charge of it and organise to have the system jetted. .if it's a group system then there are changes that should cover this

The people responsible for it are the OP and their Neighbour's that discharge into it.

missgeorge wrote: »

Thanks for the replies. It is a public system - not sure if the stink is back up from the pipes that are on the council's maps. I suspect it's a blockage further down the system - baby wipes or a fat berg. If people along the street pour white spirits down their drain, I can smell it in our utility room. The blockage could be in any one of their pipes leading into the shared sewage pipe that runs behind our houses. Not to be holier than thou - but we never put anything dodgy down the toilet or drain because we're so conscious of having the drain inside the house. The confusing part is how intermittent the smell is - it can vanish for 48 hours and then come back with a vengeance and then slowly disappear again. Surely a blockage doesn't come and go?

It is not a public system. Public system ms have a legal way leave attached to them and hence your extension would have never been allowed to be built over it.

Is this sewer out your back garden?

tradesman

You need to fit a double sealed recessed manhole cover. (recessed to take the floor finish) There is no way the smell should come into the house. These manhole covers are used all over the place including hospitals etc.

Calahonda52

Op as its important to get this sorted quickly as the fumes can kill,
look at this link
http://www.galco.ie/access-covers-recessed-covers.php
I have used them in the past, the seal can be augmented with normal car grease

elperello

missgeorge wrote: »

Thanks for the replies. It is a public system - not sure if the stink is back up from the pipes that are on the council's maps. I suspect it's a blockage further down the system - baby wipes or a fat berg. If people along the street pour white spirits down their drain, I can smell it in our utility room. The blockage could be in any one of their pipes leading into the shared sewage pipe that runs behind our houses. Not to be holier than thou - but we never put anything dodgy down the toilet or drain because we're so conscious of having the drain inside the house. The confusing part is how intermittent the smell is - it can vanish for 48 hours and then come back with a vengeance and then slowly disappear again. Surely a blockage doesn't come and go?

Is anyone on the system engaged in any business or hobby that would entail intermittent discharges to the sewer?

You might consider keeping a diary of when the odours occur to help you establish a pattern.

missgeorge

Folks, thanks for all your suggestions about the sewage smell coming from the manhole inside my utility room. Think I'm going to have to get a CCTV drain survey. Anybody got any experience of this in terms of cost, whether I should hire a company who does the survey AND repairs? Should I pay for a DVD of the drains, or will a map when it comes to getting any problems fixed?