how do i troubleshoot problems with my hot water heater?

well, i can't say for sure it's my hot water heater, but all of a sudden, we're running out of hot water really fast. used to be having 2 people showering and having the dishwasher or washing machine would bring the chills to the 3rd person to shower, but just this evening, the water went cold while 2 showers were going on simultaneously. the pilot is still on and i can't really tell anything beyond that. any ideas on what i should check?

Answers:
Well to start off Im a Plumber and this is a common problem to say the least.
But and I hate to use that word. But you didnt say ifd it was Electric or gas That plays a big part in it.
And also what size it is 40/50/75 gal
If its Electric it could be a Element that is out
If its gas The thermostat could have went out on you. Not all the way but the easy way to say this is lets say the HWT thermostat thinks the water is 135DEG- But its only 90DEG
This would cause this problem.
If you would like to E-Mail me with
Model #- SER#
What kind IE- AO Smith/Bradford white (whatever kind it is)
How many gal
Electric or gas
If you give me the numbers off the tank you wont need to give me the Gallons on it the numbers will tell me everything I need to know.
The one thing I can tell you is that most people use there tanks year after year and bever maintain it. And thats Why I replace so many in a year.
On the bottom side of the tank you will see a hose bib.
It will be brass or plastic. What you need to do is hook a hose up to it and open the valve and let out about 10gal of water or untill its clear. This will flush out any dirt in the tank and give it more life.
NOTE- Sometimes when you open a plastic valve they never want to shut off correct and they drip. If this happens to you open it and close it a few times this works sometimes if not then you will need to replace it. ( REPLACE WITH BRASS) You could use a cap on it but this is not the correct way to do this.
1 Other thing even though the tank goes from warm to very hot. You should never put it all the way up. There are a few reasons for this.
1 You will burn the He** out of yourself or someone that uses it and does not know you have it that hot like a child
2 it tanks the life out of the tank.
Anyways E-Mail me with that And I will tell you what to do if you have not solved this yet
GoodLuck

Other answers:
How old is it? Is it gas or electric? If mineral deposits are a problem, like lime or rust, a good thing to do is hook up a hose to the drain spicket of the water heater and flush it out for apoxamitly 10-15 minutes. If electric check the upper and lower elements. If one of these are malfunctioning you will get about half the hot water
How old is it? Is it gas or electric? If mineral deposits are a problem, like lime or rust, a good thing to do is hook up a hose to the drain spicket of the water heater and flush it out for apoxamitly 10-15 minutes. If electric check the upper and lower elements. If one of these are malfunctioning you will get about half the hot water
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