Leaking hot water heater - help

[Justin Case]

I have a leaking hot water heater. It is not leaking much at all and I cant find where it is even coming from.
I starred at it 10mins and did not see a drop but the floor is wet.
I believe it is leaking from the top under the ridge where the metal cover ends since i see water mark stains on the ridge and top half.
My tenants said the city was messing with the street water lines and then they noticed the water heater leaking immeaditly. They think it was the pressure of the street lines.

The water still heats up asap.

I know nothing about the water heaters.. How can i start to trouble shoot this and find the leak around the tank?

Thanks

[Marc Freislinger]

I've seen water heater leaks in couple different places.

The water lines entering the unit: These can leak if the water heater gets bumped, or if the rubber seals wear out. As someone else pointed out, they are very easy to tighten or replace.

The t&p valve: The drain valve near the top of the tank will leak if the water heater has too much pressure. That could be caused by a bad element or thermostat. (or control unit in a gas WH). Once that valve opens, it may not close all the way, so replacing the valve might be necessary, even if the pressure has already reduced itself.

Elements: Someone else mentioned this too I think, if you have an electric water heater, it may leak around the elements, this is visible if you take the covers off. New elements are inexpensive and easy to replace.

Drain valve: I've seen the drain valve leak at the bottom of the tank if it gets so much lime in it that the water can seep through. Again, these are easy to replace. If you do replace it, replace with a brass valve and not a plastic one, it will make your life easier in the future.

Tank: If the water is leaking inside the metal case, or onto the gas burner, and you can't tell where its from, there's a good chance the tank cracked. Most water heaters will last 10-15 years, but 5-10 isn't unheard of with hard water. If it's a gas WH, reach under the tank where the burner is and feel for rust and moisture. If the tank is cracked, the water heater needs to be replaced

Anode Rod: I've never seen a tank leak here, but it is another item that screws into the tank, so i suppose it's possible. The rod is topped by a square bolt looking thing on the top of the water heater, it also just screws out and back in.