A couple of things. I have two bathrooms and one of them, you cant really take a shower due to not enough hot water. You can shower for about 5-10 mins and the water is now warm, even when the handle is all the way on hot. Also a outdoor faucet has cool, then hot, then cold water coming out of it. I have checked the pipes and they are ran correctly, (hot-hot, cold to cold). My bathroom has no problem due to the kind of shower I have. This a new build and the water is not "hot" anywhere. I have the temp. on the tanks 130. Help Carolyn Stump

  • 1
    Make sure all your shutoff valves are open and recheck the pipe runs. If you've got hot water coming out of an outdoor faucet, somethings wrong. If it's a new build, get with the contractor to fix the problem.
    – JACK
    Feb 1, 2021 at 16:57
  • @JACK sounds like a recirc pump...
    – MonkeyZeus
    Feb 1, 2021 at 18:25
  • Who did the work - a professional or a DIY?
    – Criggie
    Feb 2, 2021 at 0:12
  • Do you have forced-air heat? A cold water line running through a duct may allow a length of pipe to become warm (or hot) when there is no water flowing.
    – HABO
    Feb 2, 2021 at 3:59
  • Since one of your showers apparently can run hot forever, this points to a problem with the hot-water lines going to the other bathroom. Check for incorrect plumbing connections as well as local backflow preventers. How many different hot-water tanks do you have? If the bathrooms are on different tanks, then the location of the problem is easy to find. Feb 3, 2021 at 15:38

1 Answer 1


A few possible causes of the issue:

  • There are long runs of uninsulated cold and hot water pipes next to each other. The hot water pipe should be insulated to keep the water inside hot, and the parallel pipe cold. If you have any way to access the supply lines, insulate at least the hot water pipe. It is also possible that insulation in a wall or crawlspace, as opposed to pipe wrap, has been damaged. For example, if water has leaked into a wall, perhaps from an ice dam, it can cause wall insulation, particularly cellulose insulation, to clump and settle, and rodents can remove pipe insulation in a crawlspace.

  • Backflow from convection and from expansion of water in the hot water tank is pushing heated hot water backwards, into the cold water supply line, wasting that heat. Install a backflow preventer. A quick test for that issue is to partially throttle the water entering the heater, but do not reduce it to a trickle, let the tank overheat and be damaged! If water in the outside tap is now noticeably cooler, backflow is at least one culprit. Reopen the heater valve after testing!~

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