Common leaks
Water heater leaking from the top
A leak at the top is usually good news: it's almost always a connection, not the tank. The trick is finding which fitting is wet and telling a real leak from harmless condensation.
Get your specific answer Open the triage with a top leak pre-selected — add the age and type for the verdict and cost.What leaks at the top
- The cold and hot water connections. The two pipes at the top — the cold inlet and hot outlet — can leak at a loose or corroded threaded fitting, a nipple, or a flexible supply line. Tightening or replacing the fitting usually fixes it ($150–$400 with a plumber).
- The T&P relief valve. On many heaters the relief valve is seated on top or the upper side. If that's where the water is, treat it as a relief-valve leak — and never plug it.
- Condensation. On a cold day, or right after a big hot-water draw, moisture can bead on the tank and connections and drip. If it clears up as the tank heats and you can't find a wet fitting, it may just be condensation — not a leak.
How to find the source
Dry the top of the tank and both connections with a towel, then check back in a few minutes with a flashlight. The fitting that's wet again is your leak. If the whole top is damp but no single fitting is dripping, suspect condensation. Because a top leak is rarely the tank, the fix is usually at the connection — but on a heater past its service life, weigh it against a replacement anyway.
Before you touch it
Shut off the cold water and cut the gas or power first — the pipes carry scalding water. See the full shutoff steps, and if the water is actually coming from the bottom, read that guide instead.
Top-leak questions
What should I do first when my water heater is leaking?
Follow the safe order: (1) cut the gas or power to the heater; (2) close the cold-water shutoff on the pipe entering the top of the tank, or your home's main water valve if you can't reach it; (3) contain the water — you don't need to drain the tank for a leak; (4) leave the T&P relief valve alone if that's where the leak is; and (5) call a licensed plumber if it doesn't stop, the tank is leaking from its body, or you're unsure. Enter your leak's location in the triage tool for the specific cause and next step.
Can I take a shower if my water heater is leaking?
Once you've closed the cold-water shutoff, you have whatever hot water is left in the tank and no more, so plan on cold showers until it's fixed. Before that, it depends on the leak. If water is coming from the T&P relief valve, don't run hot water at all until a plumber has looked at it — that valve only opens when temperature or pressure is too high. Stay away from the unit if the leak has reached wiring, a plug, or the burner area, and remember the water can be scalding at 120 °F or more. A small drip at a fitting on an otherwise healthy heater is the one case where short-term use is usually fine.
Should I repair or replace a leaking water heater?
It comes down to where it's leaking and how old it is. A leaking connection, drain valve, or relief valve on a heater under about 8 years old is usually worth repairing. Past roughly 8–12 years a storage tank is near the end of its service life, so a repair competes with a replacement you'll need soon anyway. A tank leaking from its body is a replacement regardless of age. The triage tool weighs your leak location against the unit's age to give you a specific repair-or-replace call.
How much does it cost to replace a water heater?
Installed replacement in 2026 typically runs about $700–$1,800 for an electric tank, $1,000–$3,000 for a gas tank, and $1,200–$4,500 for a tankless unit — electric at the low end of that range, gas at the high end — with labor making up roughly 30–50% of the total. A straightforward same-location swap is at the low end; relocating the unit, upsizing gas or venting, or bringing old connections up to code pushes it higher. These are typical ranges, not quotes — get two or three local estimates.
Can I still use my water heater while it's leaking?
It's better not to. Even a slow leak can worsen quickly, waste water, and cause water damage or mold, and a leak near gas or electrical connections is a hazard. The safe move is to shut off the water and the gas or power, contain the leak, and get it looked at before running it again. If it's leaking from the tank body, keep it off — that unit needs replacing.