1996 rheem gas hot water heater water leaking at drain valve can this be capped off?

Identify water heater valve:
http://waterheatertimer.org/Repair-water-heater-valve.html

Gene
h

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Yes, if you are talking about drain valve:
Identify water heater valve:
http://waterheatertimer.org/Repair-water-heater-valve.html

Do not cap off TP valve or TP overflow tube

Gene
h

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

If the drip is coming out of drain valve: Put a hose cap over end of drain valve.
If water is seeping out of cracked drain vale, then replace it.
If the leak is seeping around previously sealed threads, then tank may be rusted beyond repair.
http://waterheatertimer.org/How-to-replace-water-heater-drain-valve.html
http://waterheatertimer.org/Leaking-water-heater.html

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

What brand, model, and approximately how old is water heater?
This is important because water heater designs are changing quickly.
Did you remove door over combustion chamber to access thermocouple?
Newer Rheem water heaters have air intake under combustion chamber that has to be blown out using compressed air.
If this is different brand, then use mirror under water heater to see air intake.
Set water heater on bricks to avoid high water. Make sure drain line out of drip pan is 3/4" and terminates in good drainage location.
http://waterheatertimer.org/How-to-troubleshoot-gas-water-heater.html

Put brass garden hose cap over drain valve.
http://waterheatertimer.org/How-to-replace-water-heater-drain-valve.html

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

1) If leak is simple, then put garden hose cap over end of drain valve.
Pick up hose cap in garden department at home center or hardware store
http://waterheatertimer.org/images/garden-hose-thread-cap-76.jpg

2) Or install a garden hose and run to a drain until valve can be replaced.
The hot water will not last as long for showers until valve is fixed

3) If drain valve is cracked, it needs to be replaced.
If you are a DIY adventurer, then replace drain valve.
Since drain valve is plastic, expect to use every tool you can borrow when the plastic valve breaks off.
http://waterheatertimer.org/How-to-replace-water-heater-drain-valve.html

4) Call a plumber who will prefer to replace with new heater.

5) If you want adventure, then replace heater yourself and save $400 installation. Here in Houston 2011, electric heater costs 220 and gas 330 at local box store. Offer 10% less.
Open following link for gas installation, and use basic information for replacing electric.
http://waterheatertimer.org/How-to-install-gas-water-heater.html

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For a price, expert works with you while you work on timer or any do-it-yourself project.
Fixya is always less expensive than a service call.

If you mean the drain valve, then buy garden hose cap at home center.
Cap will have rubber washer that seals tank.
If drain valve is plastic, the cap may not thread on without sanding down end of plastic drain valve.
Otherwise replace drain valve, which is simple if drain valve is brass, but can be difficult if drain valve is plastic.
Turn off power to water heater: Electric: turn off circuit breaker. Gas: turn knob to pilot.
Turn off water, open bathtub spigot on Hot side, drain water heater, remove drain valve with wrench.
If plastic drain valve breaks while being removed, then 'gently' break out broken part using hammer and big screwdriver.
Buy new drain valve at box store in water heater department.
Put teflon tape on new drain valve threads.
http://waterheatertimer.org/Water-heater-is-leaking.html
http://waterheatertimer.org/Water-heater-will-not-drain.html
http://waterheatertimer.org/Clean-sediment-out-of-water-heater.html

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For a price, expert works with you while you work on water heater or any do-it-yourself project.
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When you say drain valve, do you mean TP valve?
Two different things: -drain valve and -TP valve

-Drain valve is located near bottom of tank and has hose thread on end.
-TP valve is brass and is located on side of tank tank near top on , and has a pipe that runs down within 6" of floor, or pipe goes into a drain pipe. DO NOT CAP OFF TP VALVE because this is safety outlet that prevents extremely hot water from rupturing tank.
http://waterheatertimer.org/Leaking-water-heater.html

1) If drain valve located near bottom of tank is leaking, it can be capped with a garden hose cap from hardware store-home center. Thread cap on end of drain valve.

2) If TP valve is leaking.
a)Turn down thermostats on water heater
http://waterheatertimer.org/How-to-adjust-water-heater-temperature.html
b)Replace TP valve
http://waterheatertimer.org/How-to-replace-TP-valve.html
c) Install expansion tank on incoming cold water line
Buy expansion tank at hardware-home center-plumbing supply and tee straight out from cold water line and attach expansion tank. About the size of small football.
http://waterheatertimer.org/images/Expansion-Tank-1-82.jpg


4) Mythbusters blows up a water heater for your enjoyment U-tube
Video shows that extraordinary pressure is needed to blow up heater.
This event has only been reported once in past 10 years that I have read, and it blew out side of home. Stats for this type event don't exist in insurance company records, so you are safe - just don't cap off TP valve.

5) Add a comment for more free help.
Also take advantage of fixya phone service.
For a price, expert speaks with you over phone while you work on heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

You can try to crack it open and get a little piece of crud out of there, I'm sure that is all it is, Just get a tray or something to catch the water, It should stop it, If it gets worse, turn the water off to the heater, then open the valve and hope the bigger piece of crud comes out. It is about all you can do, other than drain the whole thing and take the valve apart and replace the rubber in it. Check it out, Hope this helps.

If you are reffering to the drain valve at the bottom of the hot water tank. It may be leaking due to the O ring being cracked or worn out. You can either drain the tank and replace the valve or you can buy a hosebib brass cap and thread it on the existing valve. There is no cause for alarm when doing this as this valve is just to drain the tank when replacing your hot water heater

drain valve must have already been leaking, that's why someone put the cap on. It's ok to cap the drain but never the pressure/temp relief. If the water is coming out of the drain (not around it) you could either replace the cap or the drain valve to stop the leak - otherwise it's time for a new water heater.