Need help with water pressure- hot water taps fine, cold water taps are not

Discussion in 'Plumbers' Talk' started by MC92, Sep 7, 2021.

  1. MC92

    MC92 New Member

    Hi, I'm sorry if this isn't the place to ask, I've been Googling this issue and the search results either take me here or give me "cold water good, hot water bad" results which is the opposite of my issue.

    This has been an ongoing issue for a little while. I assumed the problem was because of the water shortage here in NI over the summer but I've checked with my water company and they've done nothing on their end and my neighbours are having no problems.

    My issue is the title, the cold water taps in my house (kitchen, bathroom sink, bathtub, even the outside tap in the garden) all have incredibly low water pressure, like, it will take a good 2 minutes to fill a kettle and if I tried to fill the bath with just cold water, I'd be there all day. It also affects the shower since the water pressure is low, the shower pressure is pretty terrible and the temperature is all over the place.

    The hot water taps are fine, even if the water hasn't been heated by turn the heating on, the water will still come out with a lot of pressure in all the hot taps with no issue at all. If the water is hot, again no issues at all in those taps.

    I found the stop tap in my kitchen for the cold water tap and turned it as far as I could (which wasn't far, it was almost as far as i could be before I got at it ) and it didn't change the pressure at all,

    Could it be the outside stop tap needs opened up? Or will that not help at all?

    Any help with this will be appreciated
     
  2. dcox

    dcox Screwfix Select

    We need to establish what type of water heating system you have first. I expect you have a cold water tank in your loft feeding a hot water cylinder that’s heated by your boiler or immersion heater. Can you confirm?
     
  3. terrymac

    terrymac Screwfix Select

    Are all cold taps / shower fed directly from the mains supply ?
    Did you previously have very good mains pressure ,if so when did it drop ?
     
  4. MC92

    MC92 New Member

    Yeah, that's exactly it, cold water tank in the loft and a hot water tank downstairs.

    I'm honestly not sure if its fed from the mains supply, but the pressure dropped at the start of the summer, around June I'd say
     
  5. terrymac

    terrymac Screwfix Select

    Turn your stopcock off ,if cold outlets then give no water they are from the mains.
    Ask water supplier to check pressure at their stopcock,if that's ok ,then you either have a severe underground leak on your service pipe ,it's constricted,or your internal stopcock is knackered
     
    WillyEckerslike likes this.
  6. MC92

    MC92 New Member

    Hi, turned the stopcock off, only the cold water tap in the kitchen stopped. Both bathroom sink and bathtub kept running. Left them running for a little while to make sure it wasn't just a little spurt of water then it cut off, but both kept going.

    Any idea why only the kitchen tap shut off?

    And ill contact the water company again.
     
  7. Bob256

    Bob256 Member

    Your upstairs cold taps must be fed from the cold tank in the loft, whereas the kitchen tap is fed directly from the mains. The upstairs taps would therefore run as long as there is water in the tank (but the tank won't be being replenished).

    However, I would have thought that this would mean the pressure in the upstairs cold taps is independent of the mains pressure so it doesn't make sense to me why you should be experiencing low pressure in all your cold taps.
     
  8. MC92

    MC92 New Member

    Sorry if I wasn't clear, the upstairs has no taps at all, all of the taps are downstairs. No toilets or plumbing upstairs at all.

    So when I turned the stopcock off in the kitchen, I just went to the room next to it which was the bathroom and the taps were still running even when the kitchen tap wasn't

    edit: but yeah, even after turning the kitchen tap off, still low pressure in the bathroom
     
  9. Bob256

    Bob256 Member

    OK, so it still sounds like the cold taps other than the kitchen are fed from the cold tank.

    If you had said that you had low pressure in the kitchen but the others are OK, or vice versa, I could have understood it - you either have a problem with incoming mains pressure or with the plumbing from your cold tank. But for both to be affected, I'm baffled - unless you have two separate problems. I'll have to leave it to the experts to chip in I'm afraid.
     
  10. terrymac

    terrymac Screwfix Select

    Show us a pic of your mains cold stopcock. Have a look at the loft tank ,specifically the outlets at the bottom of the tank to see if one of them is obstructed, and check the water level.
    If your mains pressure is very low ,the loft tank will not fill quickly enough when water is running ,hot or cold or both ,from the tank .That could cause an air lock ,and result in bathroom taps running slowly. Usually the hot water would run slowly or not at all first ,because the outlet from loft tank to hot water cylinder should be higher than the cold outlet in the tank ,but yours maybe plumbed badly.
     
  11. MC92

    MC92 New Member

    Sure.

    [​IMG]

    [​IMG]

    And ill check the loft later after work and see what's going on up there
     
    terrymac likes this.
  12. terrymac

    terrymac Screwfix Select

    Cheers , can you rotate it 4 or5 full turns in both clockwise and then anticlockwise directions , does it move freely ?
     
  13. MC92

    MC92 New Member

    Yes, 4-5 turns each way before it stops, no issues turning it, it moves pretty freely

    Do have one thing to note, not sure if its relevant tho but you mentioning rotations made me check, the bathroom sink and bath cold tap can only be turned once, not even a full rotation before it stops, I tried to turn it beyond that and felt like I was going to break the tap, while the hot water taps can both make several rotations.

    I hadn't really noticed this before because the pressure was fine and only needed 1 turn to get good cold water out of it buts barely 1 full rotation and it stops.
     
  14. terrymac

    terrymac Screwfix Select

    Sounds like those taps have quarter turn valves ,so they only turn 1/4 to open or close ,assuming they always operated that way ?
     
  15. MC92

    MC92 New Member

    I honestly hadn't noticed before, the cold ones only do a small rotation, the hot ones can be rotated 4/5 times

    Didn't think it was important but had to make a note of it I guess, will check the loft now I'm off work and see what's going on up there
     
  16. terrymac

    terrymac Screwfix Select

    Show us pics of bath and basin taps . If basins hot and cold taps are a matched pair they should operate the same way ( same with baths two taps). If tap us supposed to rotate several times to open fully ,and it doesn't ,you wont get full flow !!
     
  17. MC92

    MC92 New Member

    [​IMG]

    [​IMG]

    And here's a video of the cold tap low pressure and 1 turn before it stops while you can see the hot water tap lets me keep rotating it



    Need to clean my tiles too, so ignore the mess haha
     
  18. terrymac

    terrymac Screwfix Select

    Those cold tap valves need ,stripping / servicing or replacing . They are quite simply not opening fully.
     
  19. MC92

    MC92 New Member

    Thanks!

    What about the low pressure in the kitchen and the shower? The kitchen is a different tap, just a little lever and obviously the shower has issues with the water pressure too
     
  20. terrymac

    terrymac Screwfix Select

    Is your garden tap mains fed ? Usually they are ,I would remove it from the supply pipe ,and see if the pressure is still very low. If it is ,then the issue is as I outlined yesterday at 6.09pm.
    With regards to your shower ,We don't know what type it is ,show us a pic please.
     

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