Water – Gas hot water tank leaking – water turned off, what about gas? Repair or replace

gashot-waterwater-heater

My water heating tank has sprung a leak – out of the top (fortunately?) Whoever installed this thing didn't do a proper job of preventing galvanic corrosion, so the tank input is corroded (irreparably, I believe) and leaking.

I turned off the cold water input but am anxious about the gas line. Is there harm in leaving the gas on? I guess I'm worried about having to turn it back on and deal with igniting the pilot light, though I don't think that's likely, the tank must be replaced ASAP and I won't be using it again in its current state.

There are a couple images attached – you can see where water has been running away from the corroded input. In one image, on the left you can see the gas line for the furnace – there's a similar line just above for the water heater. Presumably I can just turn the knob to turn off the gas – should I turn it off on the tank, too? The tank has a knob with positions marked "off", "pilot", "on". Turn off the mainline first and let the pilot burn the remaining gas in the line before turning off the gas on the tank itself?

Can this be repaired? The tank will be 12 years old around November and is still under warranty, but I don't think that will cover poor installation. I only moved in within the last year, wish I'd caught this during the walkthrough. The mortgage includes a home warranty, but it doesn't cover corrosion!

Corroded cold water input on hot water tank
Contrast between hot water output and corroded cold water input on hot water tank

Best Answer

The straightforward solution is to call a plumber to replace the heater. If you are not skilled at sweating copper and have the equipment, then this job is too difficult.

If I were going to repair the leak without turning off all the water to the house, I would cut out enough of the tubing on the tank side of the valve to allow unscrewing the copper female adapter. Then clean up the threads and solder up a new fitting with tubing so that you are not heating the water heater tubing. Then screw it on and finish by soldering the other end.

Before cutting into the tubing, you would turn the gas at the heater to pilot, then turn the cold supply off. It appears the leak is on the cold supply side. Open a hot tap somewhere to relieve pressure in the tank and drain the tank down a little.