Mains feed into two houses

[Noopy]

Hi, I am installing a new kitchen and have a question about existing mains feed, the lead pipe into my house changes to copper just after it enters, the feed supplies my house and also has a spur which goes into next door. I know they have some form of pump but not sure where or what this is fitted to, however when I turn on my cold water tap in the sink, which is direct off my incoming mains it sometimes feels like there is a lot of pressure behind it.
Should my feed (and possibly theirs) have some form of non return valve and would this ensure that any pump my neighbours use does not affect my supply?
Thanks

 

[ChrisR]

They won't have a pump on the mains, that would be v v unusuall and only for poor mains pressure which you don't have.
If you had a brand new installation you'd have separate supplies with non return valves etc.
Your arrangement ios all too common, and can be a problem if one of you needs to turn the mains off, so get yourselves your own internal stopcocks if not already fitted.

 

[Noopy]

Thanks Chris, the pressure does drop when we both run water at same time, if I am fitting new kitchen I assume it would be best to fit a non return valve to both feeds while I have all the pipework exposed?

 

[swidders]

Now is as good a time as any, but make sure that you install these, the stopcocks and a drain off valve in a reasonably accessible point. You will then:
1/. Not be able to contaminate each other's water supply
2/. Enable shutdown of your own pipework without having to go outside
3/. Drain your own pipework without getting soaked (this could be useful if you are going to leave the house empty for a while during cold weather spells !!!!!!!!!)

 

[ChrisR]

The non return valves won't make any difference you'll notice. They would only do anything if the mains pressure failed.
Double check (non return) valves are a requirement for NEW installation, not old ones. I'd avoid them, they can severely reduce your flow, and make a racket.

 

[swidders]

The non return valves won't make any difference you'll notice. They would only do anything if the mains pressure failed.
Double check (non return) valves are a requirement for NEW installation, not old ones. I'd avoid them, they can severely reduce your flow, and make a racket.

Well, I didn't know that! Thanks for the info.

 

[ChrisR]

They can bounce open and shut at low flows. The two can be at slightly different frequencies too. Aaargh!
"Cured" one 28mm one by putting a smaller one 15mm across it in parallel. Others are silent, at the same pressure.

 

[swidders]

Not as experienced as you here and not come across this problem before.

Any idea about the noise from neighbour's "pump"????

 

[Noopy]

Many thanks for your replies, just the stopcocks and drain off valve then when I fit my new kitchen, wanted to find this out before I started, cheers