One of our 2 showers uses all of the hot water in about 10 minutes...

We have two back to back-bathrooms. They both have the same 2.5 gpm shower-head. The showers are the old two handle type, not the single handle type with a mixer valve.

When we shower in the second bathroom, but not the first, it uses up all of the hot water in the house in about 10 minutes. All the faucets in the house run cold. We have a 68 gallon water heater.

This only happens in that one shower, not the other... I've replaced the shower head and that didn't make a difference.

Any help or ideas would be appreciated!

What kind of shower control? Single lever or 2 handle?

2 handle. Thanks.

If they are back to back and usually on the same line then you probably are having a
problem with the faucet. I would try to replace the cartridges first and see what happens as
replacing the faucet will be harder to do being back to back. Why a house is built like this
is beyond me.

Thank you!

No offense to you David, but these contractors don't have to open up a fiberglass surround and try replacing
these faucets. Very hard to solder in a small hole. Moen does make a large plate for this problem.

I can’t see how this would happen. If both shower heads have the same output, and the same water temp coming out, would’t it be impossible for this to happen?

In order to drain the hot water faster than the same output as the other shower, either 1) the shower heads aren’t actually the same and one is putting out more gpm, or 2) the output is the same on both, but the water temp is higher

pcride said:

I can’t see how this would happen. If both shower heads have the same output, and the same water temp coming out, would’t it be impossible for this to happen?

Click to expand...

Yes, unless there is a leak in the pipe carrying hot water between the valve and the shower head. Presumably the OP would have noticed the resulting flood.

It seems more likely that the flow rate is not as claimed on the head in the shower which uses water faster. Perhaps the internal flow resistance mechanism has failed? Easy enough to test, just turn on the cold water (only) all the way in the shower and time how long it takes a bucket to fill. Or swap the shower heads and see if the problem moves with it.

I have never heard of a 68 gallon water heater. Your dip tube maybe the issue where it isn't allowing all the hot water in the tank to be used.

Sounds like possibly a dip tube issue to me