Last reviewed and updated: 2026-09-28
Look at where the water is. Drips from the top usually mean a supply connection, not the tank. Water from the temperature and pressure relief discharge pipe means the valve is doing its job or has failed. Water rising in the drain pan from underneath usually means the tank itself has gone, and that is a replacement rather than a repair.
Where the water is tells you what failed
| Where you see water | What it usually is | How urgent |
|---|---|---|
| At the connections on top | A supply fitting or a failed flex connector | Tighten or replace; not urgent |
| From the T&P discharge pipe | Relief valve weeping or the system over-pressurized | Investigate now; it is metered and continuous |
| Around the base, in the pan | The tank has corroded through | Replacement. Tanks are not repairable |
| At the drain valve at the bottom | A worn drain valve seal | Cheap fix, but it runs constantly |
| On the exterior of the tank only | Condensation on a cold fill in a humid space | Not a leak. Check again after an hour |
The one that hides. A temperature and pressure relief valve that is weeping usually discharges into a pipe that runs to a drain or outside. Nothing pools, no alarm goes off, and the water is metered every minute of it. This is a genuine cause of a high water bill with no visible symptoms anywhere in the house.
What the drain pan is telling you
A pan under the heater is there to catch a failure, not to manage a normal condition. If there is standing water in it, something is wrong. Trace upwards: dry fittings above and wet pan below means the tank. Wet fittings above means the connection.
If the pan has no drain line, or the line is blocked, the pan fills and overflows onto the floor around it. In a Marietta house with the heater in the garage that is a nuisance. With the heater in an attic or a closet above finished space, it is a ceiling.
The best place in the house to identify your pipe
This is the part worth the trip even if nothing is leaking. The supply lines are exposed at the heater, so five minutes with a torch tells you what your whole house is plumbed with:
| What you see | What it is | What it means |
|---|---|---|
| Gray flexible plastic, often stamped PB2110 | Polybutylene | Installed roughly 1978-1995. Fails at fittings without warning |
| Rigid dull-orange metal | Copper | Watch for pinhole leaks, especially in low-use lines |
| Dull gray threaded metal | Galvanized steel | Corrodes internally; low pressure is usually the first symptom |
| White or colored flexible plastic | PEX | Modern, generally reliable; watch the fittings |
Knowing the material before anything fails changes every decision that follows, from whether a spot repair makes sense to what a buyer's inspector will say about the house.
Not sure what you are hearing?
Describe the sound, the damp patch or the bill and we will tell you what it usually means in a Marietta home and what it takes to confirm it.
Age, and the anode nobody checks
A tank water heater in this climate typically lasts eight to twelve years. The sacrificial anode rod inside is what corrodes so the tank does not, and once it is consumed the tank starts going. Almost nobody checks it, which is why so many tanks fail at roughly the same age.
Find the date on the manufacturer's label. If the unit is past ten years and there is water in the pan, you are replacing it, and planning that is cheaper than doing it on a Sunday.
If the heater is dry
Then the water is coming from somewhere else, and the meter is the next step. Close the water heater's cold supply valve and watch the meter: if it keeps moving, the leak is elsewhere in the system. If it stops, the loss is on the hot side, which frequently means a hot-side slab leak and explains a warm patch on the floor.
Where these figures come from
Everything above is taken from a published source. Rates, policies and conditions change, so check the date on each before relying on it.
- Manufacturer service guidance on tank life, anode rods and T&P relief valves, general to the appliance class.
- Cobb County-Marietta Water Authority, Pinhole Leaks, for the copper identification note.
Frequently asked questions
Is a leaking water heater an emergency?
Water pooling under the tank is urgent but not usually a same-minute emergency: close the cold supply valve above the heater and the loss stops. A tank that has split and is discharging freely, or any water near electrics, is an emergency and the main shut-off is the first move.
Can a water heater cause a high water bill?
Yes, most often through a temperature and pressure relief valve that is weeping into its discharge pipe. The water goes straight to a drain, so nothing pools and nothing is visible, but every gallon is metered.
How long does a water heater last in Georgia?
Typically eight to twelve years for a tank unit. The sacrificial anode rod is what protects the tank from corroding, and once it is used up the tank begins to fail. Check the manufacturer's date label before spending money on a repair.
Is water under the heater always a leak?
Not always. A cold fill in a humid garage or crawlspace can condense on the outside of the tank and drip into the pan. Dry the pan, wait an hour and look again. Water that returns while nothing is running is a leak.