I have a tankless water heater, love it! And it's not the issue.

I have a very leaky shower. I've been in my house for almost 20 years and for the first 10, I didn't mind the very slow drip since my cat loved to hop in and drink from the flow. She's gone now and the drip has become quite a significant leak, enough that I have watched my water bill climb over the last couple of months. I know the consumer amount hasn't increased as I live alone. And with working 60 hours a week, I am struggling to find the time to actually get a plumber in the house for the repair.

My question is, am I going to harm my tankless if I'm shutting the main off before I go to bed and before I leave for work. I hate the thought of wasting water when I can give it a temporary fix, and the utility bill as well. Thanks for any advice and answers.

  • Hello, and welcome to Home Improvement. I'd be worried about that main valve; they may not be made to be turned on and off and on and off and... May 9, 2019 at 11:36
  • Main shutoff valves have far more problems from never being operated for years at a time than they do from being used regularly.
    – Ecnerwal
    May 9, 2019 at 13:12
  • What kind of shower valve do you have-central "single handle" or double handle? Is this a tub/shower with a diverter or just a shower? May 9, 2019 at 16:16

1 Answer 1


Shutting off the water is only a problem if the water heater gets drained and it tries to heat air.

To avoid that you can turn off the water heater as well.

As an experiment you can turn off the intake to the water heater and see if the shower still leaks. If the leak stops then the leak is only on the hot side of the shower valve. Then you only have to shut off the hot water to mitigate the lost water until you can get it fixed. And the heater will be right there to turn off as well.

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