We bought our house a couple of years ago and it is old and was previously divided into 4 apartments. It had two water tanks installed and we had one of them removed and we also had a plumber do a couple of other small things. I'm sure our pressure was very good when we moved in and now it's terrible. It appears to be all copper plumbing throughout. I'm wondering if whatever the plumber did has screwed things up.

I see that the main water line comes in and goes directly to the remaining hot water heater before it cuts off to service the rest of the house with cold. I'm thinking this is the problem and that it should cut off for the cold water before it goes to the hot water tank. Would this cause the low pressure problem? I'd be interested to know why if that is the case. We'll be calling in a plumber to fix things but I want to know what's going on. Any advice would be appreciated.

  • What couple of small things did the plumber do before? As far as the cold water, that should only affect the pressure if the water heater was empty and was refilling at the same time you had water on elsewhere. Any open spigots outside? Broken pipe somewhere?
    – Jeff Cates
    Commented Feb 20, 2018 at 22:14
  • 1
    I would unscrew and clean the filter/strainer/arerator on every faucet as the first step. Let us know if this changes things or not. Every cold water line splits off to the hot water heater, I doubt that this is the issue.
    – Tyson
    Commented Feb 20, 2018 at 22:31
  • The pressure is bad at all faucets including a brand new laundry faucet so I don't think it is caused by debris in faucet aerators. We have two kitchens and the faucet aerators were recently replaced in both of them in order to use portable dishwashers. Commented Feb 21, 2018 at 23:38

2 Answers 2


Unless the size of the pipe was reduced at the tee The pressure/flow should not matter where the water goes into the heater. With that said I have had gate valves fail and not open all the way after being closed for maintenance I would suspect the main cutoff valve to be the issue since copper dosent corrode and shrink down like galvanized pipe will over time. The last possibility is when the work was done some debris may have broken loose and partially plugged your valves if washerless or faucet ariators. I would be checking these items before paying for another call to the plumber.

  • Interesting. I originally thought that the problem might be with the shut off valves. The plumber installed one new shut off valve and it is in a position where it is really close up against a heating duct. It is the ball valve type with the lever. On inspecting it though it is running in a straight line with the pipe which I assume means it's fully on. The main shut off is also the ball valve lever type and it appears to be also in the fully on position, But if it might be that one of the valves has failed that would be the likely problem. I will check that out. Commented Feb 21, 2018 at 23:41

i just fixed mine. the large hex nut right on top of the outflow pipe on my John Wood, power vent type water heater has a filter/ aerator under it. once that nut was removed then the knurled nut underneath that it looks like a tub or sink drain but only its plastic. it does pull straight up and took quite a bit of wiggling with a needle-nose plier and some eco acid solution. the hard water film holds it in. seems to be merely a restriction for hard water to build up and it did. cleaned it out and problem solved

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