Posting a message to the forum will remove the above advertisement
  1. Hi, welcome to the new look - Login with your usual login details, or sign up if you don't already have an account. If you post just once, all the advertisements get automatically removed. We have some competitions coming soon, and lots of new feaures. 

Discuss Is my water flow rate acceptable in the Water Regulations area at

  1. Mphutchy

    Mphutchy Guest

    Hi, we have just moved into a new house and we are not too sure who is responsible for our poor water pressure/flow or whether we have grounds to complain at all, so some help would be greatly appreciated.

    The developers are still on site, but are now building houses a fair distance from us. we have been moved in for about 3 months. The house has 2 bathrooms, occasionally we require the use of two showers at the same time, but our water pressure/flow does not seem up to the job. When we were sold the house we were told that we had an unvented hot water systems, which works from mains pressure so we would have no problem with operating two showers at once. To be honest, even when just one shower is operating the taps elsewhere run at a very slow pace, and if another tap is run we then cower under the shower head as the water flow reduces by half. This is not just an issue we have with the hot water, if we run two cold taps in the house then the flow is weak across the two of them, but naturally we feel it more when in a hot shower!

    The internal stop cock is fully open and the pipework for hot water is 22mm. There is a pressure restricting valve just after the stop cock and this seems to be set to 3bar. (as a side note when we turn on a tap this drops down to about 1.5bar, so my guess is the supply into the house is actually at about 3 bar??)

    We have told the developer of our concerns and they checked the pressure reducing valve, cleaned it out and told us that there were no issues. This was a few weeks ago, I asked them again today, as I am sure that they need to do more. They checked the external stop cock and this was also fully on, so no issues there. So the pressure seems OK at 3 bar, but I am confused as to why we have such a weak flow of water.

    I did a test just now and the tap nearest the stop cock fills a bucket up at a rate of 6 litres per minute. This seems quite low, but is it acceptable? if not, Where should I direct my complaint, water company or developer?

    Could we be missing something? Perhaps the pressure reducing valve is faulty?

    Thanks for any help

  2. stevetheplumber

    stevetheplumber Plumber GSR

    Six litres a minute is not acceptable on a new build get the builders back sounds to me like there is an obstruction somewhere as 3 bar is a decent pressure but youve got low flowrate


    Outrageous on a new build. Get them back and don't accept being fobbed off
    • Like Like x 1
  4. Mphutchy

    Mphutchy Guest

    Thanks for your guidance. Gives me a bit more confidence to challenge them on it. I have since rang the water company and they are sending someone to have a look at the supply to house in about 3 weeks. I assume their responsibility ends at the external stop cock, so if they deem sufficient pressure and flow to the main pipes then it will be down to the builder to sort it out and as you say I don't want to be fobbed off.

    Do you think the Pressure Restricting vale could in fact be the problem. Might be giving me a false 3 bar reading, or be causing the blockage?
  5. Mphutchy

    Mphutchy Guest

    Also, I forgot to mention that before the pressure restricting valve there is a non return valve. Do these have a filter perhaps that could get clogged? Or do they sometimes cause problems?

    Would it be worth me insisting that they remove these and check they are working OK?



    You will have a combi valve with it all included. Don't mess with this as it forms part of the safety controls of the cylinder. You need a special certificate to install them. Wait for the water board to test pressure and flow rate. Have you asked your neighbors about similar issues. Might give you a broader picture.
  7. Mphutchy

    Mphutchy Guest

    Thanks, Sorry I didn't mean we have a non return valve as part of the heating (I can see that we do have the combi valve you mentioned, pressure restricting&non return combined, near the hot water cylinders).

    What I meant is that we have mains cold water in to the house under the sink, followed by our internal stop cock, immediately followed by a non return valve to stop cold water leaking back into the mains? (I guess this could only happen if there was as dramatic loses of mains water pressure) this is then followed by a pressure restricting valve, set at 3 bar. This is all cold water supply, so I just wondered if grit and dirt could have clogged this up, particularly as it's a new build and this could be causing the flow problem, although I would have thought the water pressure would push this all out?

    Not yet got to know your neighbours too well yet. I asked our immediate neighbours and they live in a smaller house so have not noticed too much of a pressure issue.

    Thanks again


    You will have a line strainer as part of the combi valve. I'd wait it out until the water board come out.
  9. TVP&H Ltd

    TVP&H Ltd New Member

    Once water board have been, if they deem it an internal problem then get the developers plumber back. But before he/she does anything with it ask to see their proof of qualification card. It should have G3 unvented cylinders, it should also have their photo on it.
  10. walterwhite

    walterwhite New Member

    If there isn't at least 20 litres flow per minute, it will never be great. Most manufacturers of unvented cylinders state this. So if you don't have that, the developers should never of specified unvented..
  11. Frelon

    Frelon Active Member

    Had exactly the same with my new build last year. Put it on my snag list, builders looked at it said it was OK! I put up with it for a couple of months and called Southern Water who came out and checked the water meter/stopcock! Seems the impeller on the water meter was blocked with building sand and was not turning!! This was cleaned out and pressure was as it should be. Result was free water for six months as meter was still reading a big fat zero since the house was built!!!
    Good luck with yours [emoji106]
    • Like Like x 1
  12. Frelon

    Frelon Active Member

    Oops, just realised this thread is a little old. Perhaps the OP is now sorted? Always a bonus if posters come back to the forum to tell us the problem is sorted and how it was resolved [emoji3][emoji3]
Similar Threads - water flow rate Forum Date
Glow Worm betacom 24c hot water flow rate. Central Heating Forum Jan 15, 2017
Baxi Instant 80HE not detecting water flow Plumbing Forum Jul 17, 2017
Water constantly flowing from condensate drain. Central Heating Forum Jul 16, 2017
Motorised valve allowing water flow even though spindle closed Central Heating Forum Apr 29, 2017
Low water pressure/flow Plumbing Forum Apr 24, 2017
Overflow on Worcester boiler gushing water Central Heating Forum Apr 21, 2017
Hot water being back flowing into Cold water tank Central Heating Forum Apr 13, 2017