Water Heaters - Water slow to heat and not hot enough...

Here's what I know:

- Water gets hot slower as you get farther away from the water heater. However, none of outlets produce hot water anywhere near instantly.

- Compared to having just one outlet on, the water gets hot faster (about 30 seconds) and reaches a hotter maximum temp. when two or more water outlets run at the same time. But when the additional outlets are shut-off, the maximum temp. of the hot water decreases.

- The maximum hot water temp. throughout the house isn't what I consider "really hot" (meaning too hot to touch for more than a second or two).

- The thermostat is turned up to it's highest setting.

- These observations are true both day and night, though the water does warm-up slightly faster at night.

- The house is about six years old, and is a single story (~2100 sq. ft.).

Any ideas what might be the problem? Is the thermostat broken? Does the house need a more powerful water heater? Is there something wrong with the lines?

Any help is GREATLY appreciated. Thanks!

Spinicus, Welcome to the DIY Forums
Water at the farthest outlet takes longer to get hot because it has to push all the cooled off water out first. Only way to cure that is a circulating pump install. (costs money if you don't want to wait)
You didn't say if your heater was gas or electric. If electric, it could have one heating element burnt out, forcing the other one to try to heat ALL the water.
Has your water bill increased? Could have a leak and the heater is always getting cold water added which cools temp down. Have found faulty Pressure/temperature relief valves that stay open and are directed to a location that is not readily seen.(under house, outside etc)
Could be, as you said, a bad thermostat.
Check these items out and post back. Good luck.

Thanks for the welcome and the prompt reply majak! As a new home owner, I'm glad to have found these forums.

The fact that the water farthest from the water heater takes the longest to warm-up makes absolute sense, but the water is taking an insane amount of time to warm-up (10 minutes or more). This just dosen't seem to be normal. Would a recirculator make up that much difference?

I have a gas heater, and I'm not sure about the water bill, as I've only been in the house about a week. So if there's a hidden leak somewhere, I don't have an proof yet.

If the thermostat is the problem, can I just replace that, or do I need a whole new water heater? And would a more powerful heater solve the problem?

* Just an extra note, even with the multiple faucets running and producing hotter water, that level of hotness doesn't last for more than a 15 minute shower.

If your Temp/Pressure relief valve (located near the top of the heater) is piped away from the heater, feel the pipe. You should be able to feel a temp higher than the room its in. Also you can feel the cold water inlet pipe to see if water is running while no faucets are open.
Thermostats can be changed. One story house should not need a recirculating pump. I had 2 heaters in my house (about same sq ft as yours) with 4 people here. Took one out and don't wait all that long to get to the furthest fixture.
One other thing you might check is the dip tube in the heater. It takes the cold water to the bottom of the tank and thus pushes the hot water out. If it is broken then the cold water "short circuits' and you get warm water out instead of hot. Dip tube is in the tank at the cold water supply line. Some can be pulled out and inspected.

Thanks for the details majak! I'll check things out when I get home and post back.

BTW, for whatever it's worth, it's a Rheem brand heater -- not sure what the rating is though. Does "75 gallons in the first hour" sound right? Anyway, I'm sure it's not important, just thought I'd mention.

Not sure what that is refering to. Know that a lot of 40 gallon heaters are called 30/40 which means they will replace 30 out of 40 gallons in an hour. Please do post back with anything you find or even more questions.

A 50 gallon tank might be rated with a "first hour delivery" of around 75 gallons. That means you started with 50 gallons hot, plus the burner makes up some new hot as time goes by. You are also diluting the heated water with incoming cold. After the first 50 is gone, you are just dealing with the recovery rate.

Although a well-used cliche by now, this does have classic symptoms of the infamuos dip-tube. ( google on 'dip-tube' for all the details of the lawsuits, which are long since over). Check the website for your manufacturer which by serial number will confirm if you are affected. Approximately between 1993 and 1997 almost all water heaters were affected. The fix ( replace the diptube) is easy, although you usually need to flush pipes as well. You also might have noticed symptoms of faucet aerators becoming frequently clogged with flaky white particles.


You mentioned 15 minute showers: a rated shower head would use about 37 gallons. An older shower head might use 100 gallons! So this is part of the equation.