I turn on the hot water faucet and cold water comes out. This happens everywhere around the house. Once I flush the single toilet that's on the first floor and wait 1-2 mins, hot water starts pouring out of the faucet. The second floor also has this issue where I have to flush the toilet on the second floor to get hot water anywhere on that floor. The hot water would continue to stay for about 1-3 days before having to repeat the flushing process again.

Read online that many place the blame on the water heater (which doesn't seem likely but would like to hear what you think) or the house having an old plumbing structure. If so, what can I do to fix it? Thanks!

  • 3
    How many handles do your faucets have? (1 or 2)? have you tested this on a two handle faucet? does it behave any differently? What kind of hot water do you have? How is your water pressure? Are you on well or city water? What is the age of the house? Do you have a boiler? Do you know if you have any mixing valves?
    – noybman
    Jan 3, 2020 at 1:11
  • @noybman All are two handle faucet except for the showers which are one handle and they all behave the same. Sorry but I'm not sure how to answer "what kind of hot water do you have". Not sure what's my water pressure. City water. About 1960s. Gas water heater. If I had to guess, maybe the 2 showers since whenever they are turned on (after the flushing process), the water would be scalding hot for 5-10 seconds. Afterwards, it would adjust itself to warm water.
    – Alex
    Jan 3, 2020 at 4:38
  • @cutrightjim I thought that initially as well and switch the lines but still the same issue. I'll post the picture tomorrow.
    – Alex
    Jan 3, 2020 at 4:41
  • I'm not sure why @cutrightjim suggested you swap lines without knowing that was the issue, also, it doesn't make sense to me or else, cold water would be hot and this wouldn't be a mystery for you. Can you turn off the water supply to the 1 handle shower(S) please? (all one handle units, turn off hot and cold to each). IN FACT.... if you could turn off ALL HOT/COLD everywhere, except one utility sink, (including toilets for now), and begin with that one two handle sink. Does it work? If so, begin opening valves and testing.
    – noybman
    Jan 3, 2020 at 5:03
  • 1
    @CarlWitthoft I hear ya!!! I was wondering if a tub or something would do that too, but I wouldn't think a toilet is "faster" that some sinks or tubs. It doesn't sound like the OP has mixers involved unless we're talking single handle units. So Im currently thinking there is an issue on a single handle unit. (just a guess), awaiting OP response to my test steps for hopes of a clue. @ cutrightjm I understand where you were coming from now ;)
    – noybman
    Jan 4, 2020 at 3:05

1 Answer 1


Alex here (some reason I'm locked out of the original account). It happen to be the 1 of my shower's valves. I noticed that the hot and cold water inlets were connected to the valve's sides labeled "shower" and "tub". I had to detach and weld the valve back to where the "shower" points up and "tub" points down. I also replaced the plastic cartridge where the shower handle would be placed just in case. With that, I now get hot water 24/7 without having to flush a toilet beforehand. Thank you all for the help!

  • Glad it panned out in the long run. This was one of those ones that raise an eye, but there was only a few things it could be. Congrats!!!!!
    – noybman
    Jan 21, 2020 at 2:36

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