Water leaking observed from the bottom of the tank. What's the problem? Should I replace the old 21V40-2 unit? if so, what kind of tank is ok to replace the present unit? What's the price and installation fee? Thanks.

They wear out especially if they are older. You did not say what make and model it is but if there is water coming out the bottom it is time for a new unit. The leak is still happening because even though there is not supply pressure, gravity is pulling the water out the break in the liner.

Water heaters are sealed tanks. The only places where water would normally be able to leak would be:

1. Water inlet
2. Water Outlet
3. Heating elements
4. pressure release valve
5. drain valve

Leaking at the base is indicative of a rusted-out tank. But before you trash the old one, secure power and remove the side covers where the heating elements are installed to verify they are not leaking. If they are OK, the unit probably needs replacing. And even more likely if the unit is more than 10-12 years old. Don't delay on this as leaks from rusty tanks can blow out and cause serious water damage,

Usually, this means that the water tank is leaking. It is not worthwhile to fix the leakage unless you have welding equipment. Just buy a new one.

I had the same problem. There is a 2 piece metal tank inside. The top and bottom of the tank are connected with screws & nuts, and there is a rubber o-ring between the two pieces. The grove for this o-ring is very shallow and it doesn't fit tightly, increasing the probability of misalignment during the assembly process. I was unable to fix the leak, IMHO the grove is too shallow and the o-ring is not thick enough. I decided it was poorly designed & trashed the unit.

Depending on age and condition, If you don't see any noticable leaks where pipes are fit on top of the tank, you will more than likely have to replace the heater. Try turning the power off to unit and remove the inspection plate(s) on the side. See if you can tell where the water is coming from. If you see it is leaking around the element(s), you may want to try to remove the element(s) and apply teflon tape or sealant to the threads and re-install, do not over tighten. You may have a crack in the fiberglass tank. Water is leaking down into the metal tank which is a protective cover for the fiberglass tank that stores the water. The pipe at the bottom is probably the drain for the tank. If you are going to try to re-seal the elements, you will definately have to cut the power nad drain the tank first.

Any water heater that is leaking from the bottom needs replacement. A 20 year old water heater has given you great service, you are very fortunate.

If your tank is very old than there might be accumulation of rust and debris on bottom of tank, try and purge the tank put a garden hose on the lower most water fitting at the bottom of your unit and drain the tank. Be sure to shut off the water inlet. You might even have the booklet still taped to the side of your unit and it will explain how to flush your unit.You might also want tot think about replacing your anode rod it is probably toast if old unit.

Hello How old is the tank(6+)yrs?If the tank itself is leaking replacement is the only option.

Water on floor usually indicates that the tank is leaking and time to replace the whole unit

If the water cooler is more than 10 years old, the cathodic rod is probably all used up and the tank itself is taking a big hit with corrosion. Replace the water heater if the above is true. Otherwise on newer tanks, pull the heating element access panels, scoot aside the insulation, and look for leaks. Look for leaks at the spigot and at the top connections. For gas units, look for leaks only at the plumbing connections. Gas heaters might last 15 years before replacement is needed.