I have a teenage daughter whose showers are getting longer all the time and I am getting tired of fighting with her about taking all the hot water. Therefore, my question is about installing a device that controls the flow of hot water only to the shower that she uses.

I have already tried a water saving shower head and that didn't change anything. I want to install a variable flow control device that gradually cuts off hot water flow at various pre-set time intervals. As an electrician, I can figure out how to control it, but I'm just not sure if such a device exists.

Does anyone know of such a thing or have a better idea? Also, in the meantime, if I gradually close the inlet valve to my hot water heater while she is in the shower, do I run the risk of siphoning the water from the tank and doing damage to the tank?

  • 4
    Get a separate tank for your shower. You'll never convince a woman to take a shorter shower, especially a teenaged one.
    – Tester101
    Dec 3, 2015 at 4:22
  • 5
    What problem are you trying to solve? Do you want her to use less water, do you want her not to monopolize the bathroom, do you want her going to bed or to school on time, or do you just want more hot water for the rest of the family (in which case the simplest answer may be to change when she showers). Alternatively, non-tank water heaters are a lot better than they used to be...
    – keshlam
    Dec 3, 2015 at 6:17
  • @Tester101 So true... Dec 4, 2015 at 9:47
  • That won't damage the tank. Dec 11, 2015 at 1:30
  • Did you consider asking on parenting.SE ? :-)
    – Jeffrey
    Oct 18, 2018 at 20:15

8 Answers 8


You could try raising the temp of your hot water heater. A hotter water temp will mean the flow rate from a shower will be less (more cold water and less hot water to get the same temperature), and therefore the tank will last longer.

Other than the risk of scalding (which may be a deal-breaker if you have young kids in the house), the other disadvantage is that the water heater will use a little more energy maintaining the higher temperature.

  • 2
    You could turn the tank heat up, and install a thermostatic mixing valve at the heater. Then you won't have to worry about scalding, and the hot water will be mixed with cold at the mixing valve.
    – Tester101
    Dec 3, 2015 at 13:23

They make a pretty cool device that installs on the shower arm upstream of the shower head. It's a battery operated valve that cuts the water flow back (to like 1/3 flow) after a pre-programmed time. It doesn't shut off, it cuts the flow back enough to make for a very unsatisfactory shower experience but provides enough flow for her to finish rinsing off. It will basically force her to leave the shower.

The time duration can only be adjusted by applying a special magnet from the outside, so no one but you can adjust the activation time. it is not cheap (around $90 US) but the reviews are positive. I don't normally endorse, and I do not own one, but I have never seen another product like this: showermanager

  • 3
    If you leave town and she is handy with tools, unusually ambitious, desperate for a long shower, or super pissed-off, I guess she could probably figure out how to remove the in-line valve. My daughter would do it differently, she would just continue to gripe and complain until I gave up and took it off myself. Dec 3, 2015 at 5:00

I put a ball valve on both the cold and hot water pipes coming in and out of the hot water heater to make changing water heaters easier. When my teenaged daughter is taking too long (with a warning first), I simply shut off all hot water. It results in a very quick end to the shower and a very angry teenaged daughter. (note: I've only done this a time or two out of utter frustration.)


If everyone else in the household doesn't mind taking shorter showers than you can lower the thermostat on the water heater. This will decrease the temperature at the water heater which will limit the hot water that can be used. Or install a temperature control valve on the hot water line and set it to a warm temperature. Also closing the valve to decrease the water flow will not harm the water heater it will just slow the volume of water out of the tank.


easy peasy. just a proportional control valve. you can pop it off of a PLC, arduino, whatever.



You could feed the hot water to the shower with 2 parallel pex lines and put a solenoid in one of them, as PPA suggested, and a globe valve in the other and adjust it for a trickle of hot water. Put a timer switch (manual on / timed off) on the wall as far away from the shower as possible. Make the solenoid a normally closed one so you have to turn ON the hot water with the manual switch and when the timer runs out the solenoid closes. Then she has to get out of the shower to go reset the timer.

Another thought is to replumb the shower to a 6 gallon water heater and eliminate the feed from the larger one. Then get ready for the whining.

I have been niggling with this problem for a while since my wife likes to take 30 minute showers too.

One problem is if you have any other bathrooms she will just go shower there unless you do this to all of them.

Alternative is put the gas or electric bill in her name and have it come out of her bank account. She may get responsible after the very first bill.

Then you can be the one taking long showers. 😉


If you are willing to spend time and money to "control" the problem, why not spend money to "fix" the problem and upgrade your water heater to a larger and more family friendly capacity? Instead of being the control-freak dad, you'll be the hero dad! :)

  • 1
    1) Cost, both initial and long-term. 2) Environmental responsibility. 3) Parental discipline. Not necessarily in that order.
    – isherwood
    Dec 3, 2015 at 22:02
  • The heater I have is 66 gallons and only 4 years old. Should be plenty big for a family of 4. I will try turning up the stat and using a different style of low-flow control device. sounds like an economical thing to try before I spend too much.
    – Mike
    Dec 6, 2015 at 5:50
  • Ah, yeah, that is plenty big. :)
    – alfreema
    Dec 7, 2015 at 14:51

Get thing called showermanager which shot off water flow after 5,10,15 min. It works

  • Is that a brand or generic name? If it is a brand, is there a generic name for that type of a device? Apr 20, 2018 at 15:12

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