Wednesday, December 16, 2015

Ask Utility Buddy: Our Hot Water Doesn't Last Through Two Showers

Ask Utility Buddy recently received a question from two roommates who think something is wrong with their water heater because there is never enough hot water for both of them to take showers.

They said they each spend about 10 minutes in the shower.

A 10 minute shower uses 50 gallons of water. The average water heater holds about 50 gallons, so the first person in the shower gets enough hot water. But the second roommate has an issue if they want to take their 10 minute shower immediately afterward or at the same time in another bathroom. It takes two hours for an electric water heater to fully recover and reheat another 50 gallons.

This is one of the clear advantages of a natural gas powered water heater, as natural gas would reheat 50 gallons in an hour or less. (Tankless natural gas water heaters heat as the water goes through the pipes, so there is no waiting time at all.) The roommates think their water heater is electric, so here are their options:

Second roommate will have to wait two hours before he or she takes their shower. Or....

Each roommate can make an agreement and set a timer to take a shorter shower, 5 minutes or less. You can do it!

Add an insulating blanket to your water heater to speed up the recovery and  keep the water as warm as possible as new cold water enters to refill the tank.

Ask your landlord to check if one of the heating elements on the water heater has burnt out. If that's the case, it is taking considerably longer for the water heater to recover and the hot water runs out quickly, even before the first shower ends.


  1. The average shower head uses 2.5 gallons per minute, therefore a 10 minute shower uses 25 gallons of water. If your hot water heater is set high enough (125 degrees or higher) you would be blending cold water and hot water for a typical shower. An average 10 minute shower should only be using 15-20 gallons of hot water from the hot water heater leaving plenty for another shower.
    Make sure to limit how long you let the water warm up and try not to take extremely hot showers (causes dry skin anyway). To help you could see what your shower head is rated and go to a lower gallon per minute output like 2.0gpm to save more hot water for the other room-mate.

  2. We advise setting the temperature on a hot water heater at 120 degrees to avoid scalding.