Ask The Trades - Standing water in overflow pipe

Welcome, Guest. Please Login or Register

	Jan 31^st, 2026, 3:30pm
View recently thanked users View top thanked users

Quote: Ok, so what's the speed of dark?

Ask The Trades › DIY Forum › Plumbing Questions › Standing water in overflow pipe

(Moderator: thescruff) - (Moderator Group: Board Moderator)

< Previous Topic | Next Topic >

Pages: 1

Standing water in overflow pipe (Read 8509 times)

overflowissues

GDPR opt-out

Standing water in overflow pipe
Jun 26^th, 2010, 5:47pm

Hi,

Can anyone help me with some advice on an overflow pipe that needs extending. I live in the middle flat over a basement flat in a converted terrace house. The overflow pipe from my toilet cistern and from the cold water tank used to run below my floorboards and straight out at my floor height into the back garden.

My neighbours downstairs had an extension put on the side of the house which blocked the path of my overflow pipe and it appears that their builders just boxed in the pipe to run into the roof cavity of the extension! The toilet cistern has recently been overflowing and my neighbours now have a very damp ceiling. We've fixed the toilet cistern but we now need to do something about the overflow pipe.

It's a big job to run the pipe through the roof extension as there are several joists to be drilled through. My neighbour has suggested running the pipe vertically up through the roof, but this would mean that the end of the pipe would be above the level of my floor and would effectively create a large U bend that could hold water. As this pipe is only going to be used if there is an overflow, then any water stuck in the overflow U bend could become stagnant water.

Is this a bad idea or am I being too cautious?

Many thanks
Dan

IP Logged

big_all Global Moderator Trade Member Author Offline heeelllooo Posts: 5596 Total Thanks: 10 For This Post: 0 Gender: Trade: Joiner	Re: Standing water in overflow pipe Reply #1 - Jun 26^th, 2010, 5:54pm first thought get the builder back to complete the job you can swop the innards off the cistern for an internal overflow that dischages into the toilet bowl via the syphon but that wont help with the tank
Back to top	« Last Edit: Jun 26^th, 2010, 5:58pm by big_all » big all --------------- we are all still learning IP Logged

CWatters Super Member Offline "Daddy fick it" says James Posts: 5150 Total Thanks: 58 For This Post: 0 Gender:	Re: Standing water in overflow pipe Reply #2 - Jun 26^th, 2010, 6:52pm Where is the tank? Could you run the overflow for that out another route altogether eg higher up? Go with Big_all's suggestion for the WC.
Back to top	IP Logged

overflowissues

GDPR opt-out

Total Thanks: 58
For This Post: 0

Re: Standing water in overflow pipe
Reply #3 - Jun 27^th, 2010, 9:27pm

Thanks for the replies. But the builder didn't finish the extension and my neighbours can't contact him now. It also looks like it will be a bigger job to rip up my floorboards and bathroom to try to reroute both overflows to the waste pipe than it will be to cut through the joists in the roof extension.

Is it safe to have standing water in the overflow pipes?

IP Logged

CWatters Super Member Offline "Daddy fick it" says James Posts: 5150 Total Thanks: 58 For This Post: 0 Gender:	Re: Standing water in overflow pipe Reply #4 - Jun 27^th, 2010, 9:49pm My concern would be it freezing in winter and either bursting the overflow pipe or blocking it.
Back to top	IP Logged

overflowissues

GDPR opt-out

Total Thanks: 58
For This Post: 0

Re: Standing water in overflow pipe
Reply #5 - Jun 28^th, 2010, 9:30pm

Thanks again for your replies. So the reasons for not redirecting the pipe straight upwards are, the standing water could freeze or I wouldn't notice that there was problem until the water had managed to fill up the entire overflow pipe.

I'm more worried about breaking any standards so it would be difficult to sell the flat in the future or about any health issues if water gets trapped in the overflow and becomes stagnant. Does anyone know about these?

Thanks

IP Logged

CWatters

Super Member

Offline

"Daddy fick it" says James

Posts: 5150

Total Thanks: 58
For This Post: 0

Gender: male

Re: Standing water in overflow pipe
Reply #6 - Jun 29^th, 2010, 7:45am

Here's another thought...

It sounds like the overflow from the tank may go near or past the WC. Perhaps it would be possibly to have it discharge into the soil stack?

I can see problems though.. The overflow might have to be visible to meet the regas so some form of tundish might be required? and that would also mean a trap is required to stop smells coming out of the stack. Since the overflow isn't going to run very frequently the trap might also evaporate dry. Perhaps there is a better way?

Would it be illegal to put the overflow from the tank into the WC cistern and hence into the pan when the overflow for the pan is changed to an internal type?

IP Logged

overflowissues

GDPR opt-out

Total Thanks: 58
For This Post: 0

Re: Standing water in overflow pipe
Reply #7 - Jun 29^th, 2010, 8:42pm

Cheers for the advice so far. Myneighbour will arrange and pay for the repairs but he wants to run the pipe vertically upwards through the extension roof which will create the U bend. I'd prefer that he ran the pipe horizontally to the external wall.

Is there any building regulation, health regulation or something which states that the pipe should not go vertically upwards and should instead be directed to the external wall? Does anyone know of anyone i can contact about this?

Thanks

IP Logged

CWatters

Super Member

Offline

"Daddy fick it" says James

Posts: 5150

Total Thanks: 58
For This Post: 0

Gender: male

Re: Standing water in overflow pipe
Reply #8 - Jun 30^th, 2010, 7:33am

I guess an overflow could be considered part of the cold water service?...

http://www.arrowvalves.co.uk/waterregulations/waterregsarrowvalves.pdf

Quote:

Statutory Instrument 1999 No. 1148
The Water Supply (Water Fittings) Regulations 1999

Cold water services
16.. (5) Every storage cistern shall be so installed as to minimize the risk of contamination of stored water. The cistern shall be of an appropriate size, and the pipe connections to the cistern shall be so positioned, as to allow free circulation and to prevent areas of stagnant water from developing.

Presumably it could also be a Legionnaires' disease risk if the water is warm (eg warmed by the sun). There was a report recently that said many cases maybe due to the warm water in car windscreen wash bottles.

« Last Edit: Jun 30^th, 2010, 7:41am by CWatters »

IP Logged

thescruff

Global Moderator
Trade Member
Author

Offline

Who said plumbing was
easy.
Posts: 6037

Total Thanks: 147
For This Post: 0

Gender: male

Trade: Plumber

Re: Standing water in overflow pipe
Reply #9 - Jun 30^th, 2010, 11:59pm

Don't run the pipe uphill, unless you want lots of trouble/problems in the future.

The wc is simple, you can change the siphon for one with an internal overflow as has been suggested.

The storage tank, we need to know it's position and what it feeds, would it be possible to drill a hole straight out for example, or is being in the floor the only way to hide it.

Can you access a soil or vent pipe, without the pipe being on show.

IP Logged

overflowissues GDPR opt-out Total Thanks: 147 For This Post: 0	Re: Standing water in overflow pipe Reply #10 - Jul 1^st, 2010, 6:20am Thanks again for all your replies. I should have enough info now.
Back to top	IP Logged

Pages: 1

(Moderator: thescruff) - (Moderator Group: Board Moderator)

< Previous Topic | Next Topic >

Ask The Trades › DIY Forum › Plumbing Questions › Standing water in overflow pipe