Hire the best Bathroom Renovator

sudden drop in pressure

Results 1 to 6 of 6
  1. #1
    Join Date
    Nov 2003

    Default sudden drop in pressure

    Hi all,
    not sure if I should put this thread in this forum or the plumbing one.
    I have a problem with my shower regarding the pressure- well it seems related to a pressure problem. I turn the taps on to mix hot and cold (independent taps, not a mixer). what happens is in a middle of a shower, there is suddenly a drop of cold water pressure and you basically burn yourself. Very often, when this happens, I can hear a noise like water hammer and this is a sign that I am going to be burnt so I step away immediately
    Then sometime the pressure is back to normal and the water is fine, other times I have to readjust the cold water. Then later on during the shower I will freeze because for an unknown reason the cold water is back to normal.
    I 'd like to mention that while having a shower, nobody or nothing is using any water (no washing machine, dishwasher, etc...)
    I live in a part of Doncaster, melbourne where the water in the main pipe is renowned to have a very high pressure causing frequent water hammers - if that can help with the problem.

    The shower in the ensuite does not have this problem. However the ensuite has a water saving shower head given by yarra valley while the one in the main bathroom is one bought from a plumbing show - and is supposed to be water saving as well.
    Taps in the ensuite are probably 30 years old while I changed the one sin the main bathroom 2-3 years ago.
    any body has an idea or even better the sale problem that he/she has managed to solve?

  2. #2
    pest manager bugsy's Avatar
    Join Date
    Feb 2006
    united pest managers or Australia


    do you has gas hot water?

  3. #3
    Join Date
    Nov 2003


    is it gas hot water. A 170l hot water system using gas to heat it up

  4. #4
    1K Club Member Gooner's Avatar
    Join Date
    Nov 2007


    Have you tried changing shower heads as an experiment? It may be back-pressure related or the washers in your taps.

    It may also be worthwhile to test the pressure in your cold water line. If it is excessive, it may be an idea to add a pressure regulator to the main line entering the house. This is what I did. My pressure hovered around the 10bar line (sometimes more) and I had some bad water hammer in the lines. I spent several hundred on water hammer arrestors (the gas piston types) but it did nothing. I added a PLV to restrict the presurre to 5 bar (what it should be) and water hammer is gone.

    Best way to test the pressure (I found) is to get a pressure gauge and simply screw it on to the tap in the backyard and turn on the tap. (Make sure nothing else is running).

    I certainly do not notice the drop in pressure in the house. The hot water line is pressure regulated anyway, so restricting the cold pressure will not make any noticable difference when taking a shower or for any general use where you regulate the temperature using the taps. It will only be noticable when you have a cold tap running full blast. However, this need does not arise too often in the house.

    Another explanation could be that there is something nearby that is connected to the mains line that is using a lot of water. But if this is the problem, then your ensuite, as well as your neighbours, would experience the same problem.
    I'm no expert, but know enough to be dangerous...

  5. #5
    Join Date
    Nov 2003


    I hav enot tried changing the shower head.
    I used to have one similar to the one is the ensuite and everything was ok. when I changed the one in the bathroom, everything was working well as well.
    however if I remember correctly things started to change when I changed the taps.
    If it was the taps or their washers, hoe would you test them or what type of washer would you use to avoid the problem?
    Is it a tap design problem?

    The water pressure is excessive, that's for sure.No need to test it. I have an automatic sprinklers system and when the valves switch off, you 'll hear this big water hammer.
    I am intending to insert PLV as the water hammer has destroyed twice the cold valve in the washing machine and a kitchen mixer.

  6. #6


    Put in a water pressure reducing valve, this is fitted just after the meter and its cost is about $100 plus the plumber if needed. That will reduce your pressure to a constant level regardless of mains. Obviously if the pressure drops goes below settings on the reduction valve thats tough. You will save on water and tap washers, I installed one a couple of years ago and have never changed a tap washer since. I believe all new houses in Melbourne this is a requirement. Also why is your water so hot. If you have a tank type water heater the hotter you maintain the temperature the more power you will use and the sooner the tank will wear out so thats a double cost. Turn it down till you get the lowest temperature you are happy with.

Similar Threads

  1. Drop Ceiling Truss Design??
    By chuth77 in forum Structural Renovation
    Replies: 15
    Last Post: 29th Jan 2009, 02:04 PM
  2. Ring mains - pressure drop
    By Fisherdroid in forum Plumbing
    Replies: 3
    Last Post: 22nd Apr 2008, 08:48 AM
  3. Cutting cornice with a drop saw?
    By Groggy in forum Plastering
    Replies: 18
    Last Post: 11th Apr 2007, 09:19 AM
  4. Pressure Pump - pressure switch setting?
    By Woody Allan in forum Plumbing
    Replies: 4
    Last Post: 4th Jan 2006, 04:12 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts