Why is my water heater leaking?
Where the water is coming from decides everything. A leak at a fitting on top of the tank, at the drain valve, or from the temperature and pressure relief valve is a repair, often an inexpensive one. Water coming from the bottom of the tank itself usually means the steel has corroded through, and that cannot be patched. So before you assume the worst, find the source.
We get these plumbing calls year-round across the Dallas-Frisco area, and a fair number of them turn out to be a loose connection rather than a dead water heater. Here is how to check.
First, dry everything and watch
Shut off the water supply valve at the top of the tank. Wipe the whole unit down, the top fittings, the sides, the base and the pan. Then leave it for an hour or two and come back.
This step sounds fussy and it saves people a lot of money. Water runs down the outside of a tank and pools at the base, so a leak that started at a fitting three feet up looks exactly like a leak from the bottom. Drying it and letting it reappear shows you where it actually starts.
The four places it usually comes from
The inlet or outlet fittings on top. These are threaded connections and they loosen over time, especially if the unit has been bumped or the house has settled. Usually a tightening job or a new flex connector.
The drain valve near the bottom. The plastic ones fail with age. If water is weeping from the spigot itself, the valve needs replacing. That is a small repair.
The T&P valve. The temperature and pressure relief valve is a safety device that opens if pressure inside the tank gets too high. If it is dripping, either the valve has failed or the tank is genuinely overpressurized. Do not cap it or plug it. That valve is what keeps the tank from becoming dangerous, and if it is opening, something needs to be found out.
The tank itself. If water is coming from the seam or the body of the tank rather than from a fitting, the glass lining has failed and the steel underneath is rusting through. There is no repair for this. The tank has to be replaced.
What makes tanks fail here
The anode rod inside a water heater is a sacrificial piece of metal. It corrodes so the tank does not. Once it is used up, the tank starts corroding instead, and that is the clock running on the unit.
In North Texas the clock runs faster. Our water is hard, and the mineral content both wears the anode rod out sooner and leaves sediment in the bottom of the tank that traps heat against the steel. That combination is why a lot of water heaters here start failing around year eight or nine rather than making a comfortable twelve. Replacing a spent anode rod is cheap. Replacing the tank it was supposed to protect is not.
If your unit is also giving you less hot water than it used to, that is the same story from a different angle, and we covered that in what to check when you have no hot water.
What to do right now if it is leaking badly
Shut off the cold water supply valve at the top of the tank. Then kill the energy: flip the breaker off for an electric unit, or turn the gas control valve to "off" for a gas one. An electric element that runs in an emptying tank will burn out, and you do not want a gas burner firing under a failing tank.
Then call. A slow weep can wait until morning. Water spreading across a garage floor cannot.
Repair or replace
The honest version: age plus location of the leak decides it.
A fitting, drain valve or T&P valve leak on a unit under about eight years old is worth repairing without much thought. The same repair on a fifteen-year-old tank is money you will likely spend again soon. And a leak from the tank body is a replacement at any age, because there is nothing to seal.
When it is replacement time, we size the new unit to how your household actually uses hot water rather than defaulting to whatever the builder installed, and we will give you a straight read on whether tankless makes sense for your house. Our water heater services page covers what is involved either way.
Get eyes on it before it gets worse
A leaking water heater is one of the few home problems that reliably gets more expensive the longer it sits, because the failure mode at the end is a tank emptying itself onto your floor. If yours is dripping, let us take a look.
Schedule a water heater visit or call (469) 285-4457. Same-day in most cases, written pricing before we start.
Frequently asked questions
Is a leaking water heater an emergency? It depends on the source and the rate. A slow drip from a fitting can wait a day. Water coming from the body of the tank should be dealt with immediately, because that failure tends to get worse quickly and can empty the whole tank onto the floor.
Can a leaking water heater be repaired? Leaks at fittings, the drain valve and the T&P valve can all be repaired. A leak from the tank itself cannot, because the steel has corroded through and there is no way to seal it from the outside.
Why is water leaking from the bottom of my water heater? Either water ran down from a leak higher up and pooled at the base, or the tank has rusted through. Dry the unit completely, wait an hour or two, and see where the water reappears first. That tells you which one you have.
What is the T&P valve and why is it dripping? The temperature and pressure relief valve opens if the tank gets too hot or too pressurized. A drip usually means the valve has failed or the system pressure is too high. Never plug or cap it, since it is a safety device.
How long do water heaters last in Texas? Most tank units last eight to twelve years here. Hard water shortens that, so units that are never flushed and never have the anode rod replaced often fail closer to eight.