Water heater leaking from top
Moisture or dripping around the hot or cold water connections, nipples, or nearby piping above the tank.
Start here: Start with the top fittings and any shutoff or flex connection before looking lower on the heater.
Water Heater Leak Troubleshooting
Water Heater Leaking
Direct answer: A leaking water heater is usually coming from one of four places: a loose plumbing connection, the temperature and pressure relief valve, the drain valve, or the tank itself. Start by finding the exact leak point before you buy anything.
Most likely: The most common homeowner-fixable leaks are at the top water connections, the temperature and pressure relief valve, or the drain valve. If water is seeping from the tank body or the bottom seam, the heater is usually at the end of its life.
Dry the outside of the heater, then watch where fresh water first appears. That one step separates a simple valve or fitting issue from a failed tank. If you have a gas water heater and see active dripping near the burner area, smell gas, or hear unusual hissing, stop and get a pro involved.
Don’t start with: Do not start by replacing random parts or assuming the tank is bad just because there is water under it. Water can run down the jacket from a small leak above and make the bottom look like the source.
Water at the base only?Check above the puddle first. Top fittings and relief-valve discharge often run down the tank shell.
Leak from the tank body or bottom seam?Plan for replacement. Internal tank leaks are not a practical DIY part repair.
Last reviewed: 2026-03-31
Find the leak by location before you touch parts
Water heater leaking from relief valve
Water is dripping from the temperature and pressure relief valve body or from the discharge pipe attached to it.
Start here: Check whether the valve is weeping occasionally or flowing steadily, then stop if pressure or overheating seems possible.
Water heater leaking from drain valve
Drips are forming at the drain spout near the bottom of the tank.
Start here: Make sure the drain valve is fully closed and confirm the leak is from the valve itself, not water running down from above.
Water heater leaking from bottom
A puddle forms under the heater, but the exact source is hard to see.
Start here: Dry the whole exterior and watch for the first wet spot. Bottom puddles often start higher up.
Most likely causes
1. Loose or corroded top plumbing connections
Leaks at the hot outlet, cold inlet, or nearby fittings often track down the jacket and collect at the base.
Quick check: Dry the top of the heater and fittings, then look for fresh beads of water forming at one connection.
2. Temperature and pressure relief valve leaking
Water at the side-mounted or top-mounted relief valve, or from its discharge pipe, points to a valve issue or an overheating or pressure problem.
Quick check: Place a cup under the discharge pipe briefly and see whether the valve is actively dripping after the heater has been idle.
3. Water heater drain valve leaking
A slow drip from the threaded drain outlet near the bottom is common after flushing or after the valve has aged.
Quick check: Wipe the drain valve dry and watch the spout and stem area for a new drip.
4. Internal tank leak
Rusty water, seepage from the tank body, or water appearing from the bottom seam usually means the tank has failed internally.
Quick check: If the shell stays dry above but water keeps appearing from the lower jacket seam, treat it as a failed tank.
Step-by-step fix
Step 1: Shut down the risk and pinpoint the first wet spot
A puddle under the heater does not tell you where the leak started. You need the first fresh drip, not where the water ended up.
- If water is pooling, turn off power to an electric water heater at the breaker. For a gas water heater, set the gas control to pilot or off if you can do it safely.
- Close the cold water supply valve to the heater if the leak is active enough to cause damage.
- Dry the top, sides, relief valve area, drain valve area, and floor with towels.
- Wait a few minutes and watch with a flashlight for the first place new water appears.
- Check whether the water is coming from a fitting above the heater, the relief valve discharge pipe, the drain valve, or the tank body itself.
Next move: You have the leak narrowed to one area, which keeps you from replacing the wrong part. If everything is wet at once or the leak is heavy, keep the water supply off and move to pro service.
What to conclude: Location matters more than the size of the puddle.
Stop if:
- You smell gas at any point.
- Water is spraying, not dripping.
- The leak is near electrical wiring, the junction box, or the breaker panel area.
- You cannot safely identify the source without moving gas piping or live electrical parts.
Step 2: Check the top water connections and nearby piping
Top-side leaks are common and often make the bottom of the heater look like the problem.
- Inspect the cold inlet and hot outlet connections on top of the water heater.
- Look for corrosion, mineral crust, or a fresh bead of water at threaded fittings, flex lines, or dielectric unions.
- Gently test for looseness only at accessible plumbing connections. Do not force corroded fittings.
- If insulation or a cover is hiding the top, pull it back just enough to see whether the leak starts there.
- If the leak is from house plumbing just above the heater rather than the heater itself, treat that as a plumbing repair, not a water heater part issue.
Next move: If the leak is clearly at a top connection, you have ruled out the tank and can focus on that fitting or nearby plumbing. If the top stays dry, move to the relief valve and drain valve checks.
What to conclude: Water running down the shell can fool you.
Step 3: Check the temperature and pressure relief valve carefully
A relief valve can leak because the valve is worn, but it can also be reacting to unsafe temperature or pressure conditions.
- Find the temperature and pressure relief valve and its discharge pipe.
- Dry the valve body and the end of the discharge pipe.
- Watch for dripping from the valve threads, the valve outlet, or the pipe end.
- If the valve drips only from the threaded connection to the tank, the connection may be leaking.
- If water is coming from the discharge opening or pipe end, do not assume the valve alone is the problem.
- If the heater has also been overheating, making popping sounds, or delivering unusually hot water, stop DIY and have the system checked.
Next move: If the leak is only at the valve body or threaded connection and there are no signs of overheating or pressure trouble, a water heater temperature and pressure relief valve may be the fix. If the valve is discharging water from the outlet or you suspect pressure or temperature problems, stop here and call a pro.
Step 4: Check the drain valve at the bottom of the tank
Drain valves commonly seep after flushing or as the valve ages, and this is one of the few lower leaks that can be a direct part fix.
- Dry the drain valve body, stem, and spout completely.
- Make sure the valve is fully closed by turning it gently to the closed position. Do not overtighten.
- Watch for a drip from the spout, around the stem, or where the valve threads into the tank.
- If the leak is only from the spout, attach a cap only as a temporary way to confirm the source, not as the final repair.
- If the valve body itself is cracked or continues to drip after closing, plan on replacing the water heater drain valve.
Next move: If the drip is clearly from the drain valve and the tank shell is dry, a water heater drain valve is the likely repair. If the drain valve stays dry but water still appears at the bottom seam, move to the tank-failure check.
Step 5: Decide whether this is a repairable valve leak or a failed tank
This is the point where you either make a focused part decision or stop before wasting time and money on a heater that needs replacement.
- Inspect the lower jacket seam and the tank body for rust streaks, bubbling paint, or seepage that is not coming from a valve or fitting above.
- Look for water appearing from behind insulation panels or from the bottom seam after the exterior above has stayed dry.
- If the leak has been traced to the relief valve threaded connection or a worn drain valve, replace only that confirmed part after shutting down water and power or gas safely.
- If the leak is from the tank body, bottom seam, or an internal area you cannot access without opening the heater, plan for water heater replacement.
- If the heater is not leaking but also not making hot water, switch to the water heater not heating problem page for the next diagnosis.
A good result: You now know whether to replace a confirmed valve part or stop and replace the water heater.
If not: If the source is still uncertain, leave the water supply off and have the heater inspected before it causes more damage.
What to conclude: Tank leaks are end-of-life failures.
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FAQ
Why is there water under my water heater but I cannot see a leak?
Water often starts at a top fitting or the relief valve and runs down the jacket before it reaches the floor. Dry the whole heater first, then watch for the first fresh wet spot.
Can I keep using a water heater that is leaking from the bottom?
Not for long. If the bottom leak is really coming from the tank seam or tank body, the heater is failing and should be replaced. Shut off the water supply if the leak is active enough to cause damage.
Is a leaking relief valve always a bad valve?
No. A worn valve can leak, but a relief valve can also open because of excessive temperature or pressure. If water is discharging from the pipe end, treat that as a safety issue and have the system checked.
Can I repair a leaking water heater tank with sealant or epoxy?
No practical repair lasts on a failed tank. If the tank body or bottom seam is leaking, replacement is the right fix.
What if my water heater is not leaking but I also have no hot water?
That is a different problem path. Use the water heater not heating page to check heating elements, thermostats, or other heating-related causes after the leak issue is ruled out.