I live in an apartment complex where the rooms/bathrooms are identical, and there is one gas water heater for each unit. My shower will stay hot as long as I want it to, but my roommate has to rush through her showers just to keep it lukewarm. We don't shower at the same time or run anything else that uses the water at the same time. Can anyone help us figure out why this is a problem with only one shower?

  • After hers runs out, does yours still have hot water?
    – Grant
    Mar 2, 2015 at 1:45
  • Hmm.. We're hardly ever in the apartment together but I will have to check next time we are. I think mine does get cold pretty fast after she showers. Mar 2, 2015 at 2:01
  • What size is your water heater? Is it possible you have a low flow shower head and she does not? Mar 2, 2015 at 16:03
  • - oops, double! Mar 3, 2015 at 17:19
  • Tested out what Grant asked - mine stays hot even after she showers. @organiclawndiy - it's possible that hers is higher flow than mine, considering every time she showers the curtain liner gets pulled inward. The heater is 38 gallons. Mar 3, 2015 at 17:21

2 Answers 2


So this is happening in separate bathrooms that is supplied by one water heater? You'd be surprised how quick you can go through 38 gallons of hot water especially with a high flow shower head. Newer shower heads are usually rated at 2.5 GPM, while older ones were much higher. Also check the timer on the heater. One other question, is the hot and cold water tied into one shower valve? Or is it two separate valves for hot and cold? If it's only one valve that ties the hot and cold together, that may be the problem. They use rubber parts that get swollen and wear over time and the valve may be the problem. That would explain lukewarm showers due to the 50/50 cold and hot mix.


Are you saying that your apartment has one water heater that only you and your roommate share, or that your complex provides hot water to all units?

If the complex provides hot water and if both showers get cold together at about the the same time, your plumbing is probably normal (your shower doesn't have some extra source of hot water).

The difference most likely is that you two don't typically shower at the same time of day; you shower at a time when less other people in the complex are also showering.

  • It's a heater that is only used in our unit, not throughout the whole complex, and only one shower gets cold. Mar 3, 2015 at 17:22

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