Camco 11523 drain valve
$11.99 at Amazon
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Water heater leaking from the bottom
Find where the water really comes from before you replace anything.
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Quick answer
Most water under a heater isn’t the tank. Dry it, then check the drain valve, the relief valve pipe and the top fittings. If every fitting stays dry and water still seeps out, the tank has failed: replace the heater.
Most common fix: Camco 11523 drain valve$11.99 at AmazonPrice as of Oct 24, 2026, 5:30 AM EDT · low stock then
Check it on AmazonShut it down if it’s leaking steadily
A steady leak, a wet burner area or water near wiring means stop and shut off before you look.
- 1Gas heater: turn the gas control to OFF
A. O. Smith’s manual has you turn the control knob to OFF, then close the manual gas valve on the supply line.
- 2Electric heater: turn off the breaker
Shut off power before you touch anything near the tank. A. O. Smith says to turn the power off before checking the tank for leakage.
- 3Close the cold water valve on top
That stops new water entering the tank. The tank can still drain through a leak.
- 4Keep clear of the relief valve pipe
Water from it can be hot enough to burn. If it’s putting out large amounts of very hot water, the gas manual says turn the gas off and call a qualified person.
If it’s only a slow drip, you can leave the heater running while you track it down. Put a towel or a shallow pan where the water lands, and a dry paper towel under each suspect.
My call: if the water is coming out faster than a towel can soak up, shut it down now and find the source with the tank off. A heater that’s off is just a tank of water.
Where is the water coming from?
Pick where you see it and when it shows up. The finder gives the likely source and what to do next.
A. O. Smith’s own leak guide opens with a warning that many suspected leaking tanks aren’t leaking tanks. Its electric heater guide says almost all leaks occur at connections. That’s why the finder sends you to a fitting first and to the tank last.
If the water is on top of the heater, start at water heater leaking from the top. For every kind of leak in one place, see why is my water heater leaking.
Five places bottom water comes from
Water collects at the lowest point, so a drip from anywhere on the heater can end up on the floor.
| Source | What you see | Fix it? |
|---|---|---|
| 1. Fittings on top | A wet trail down the jacket from a connection | Yes: tighten or reseal the thread |
| 2. Relief valve pipe | Water at the end of the discharge pipe | Yes: find the cause, then replace the valve if needed |
| 3. Drain valve | A drip at the spout or the valve threads | Yes: cap it or replace the valve |
| 4. Condensation, gas heaters | A small puddle after lighting a cold tank | No fix needed; it stops when the tank is hot |
| 5. The tank | Seeping from the bottom with every fitting dry | No: replace the heater |
A. O. Smith also lists things that aren’t the heater at all: other appliances nearby, leaking water lines and ground seepage. A washer hose or a sweating cold pipe over the heater can put water on the floor next to it. Look up and around before you blame the tank.
Dry it and watch where it comes back
The fastest way to find a bottom leak is to make everything dry and see what gets wet first.
- 1Mop up the floor or pan
Get the floor and the drain pan completely dry.
- 2Wipe every fitting
Dry the cold and hot connections, the relief valve, its pipe and the drain valve.
- 3Lay paper towels
One under the drain valve, one under the relief valve pipe and one at the base of the jacket.
- 4Check after an hour
Then again after the heater has run. The first towel to get wet is your source.
- 5Swab the threads
A. O. Smith’s test: push a cotton swab between the jacket opening and a fitting. A wet swab means that thread is leaking.
The swab test matters because a fitting can leak behind the jacket, where you can’t see it, and the water runs down inside the insulation to the bottom. That looks exactly like a tank leak from the outside.
A. O. Smith’s checklist ends with a clear instruction: don’t replace the heater until every possible water source has been checked and fixed. I agree with that order.
A drain valve, thread sealant and a leak alarm
The parts that fix and watch the most common bottom leaks. I’ve used every part in this kit.
RectorSeal T Plus 2
$8.78 at Amazon
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Resideo L1 leak detector
$67.64 at Amazon
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Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.
| Part | Key specs | Pick it if | Skip it if |
|---|---|---|---|
| Camco 11523 drain valve | 3/4 in. NPT × 3/4 in. male hose thread, 2-1/2 in. long, plastic | Your drain valve drips at the spout or won’t shut off. | The leak is where the valve threads into the tank and the tank port is rusted. |
| RectorSeal T Plus 2 | PTFE thread sealant, NSF 61 non-toxic, rated for hot water to 203°F | You’re resealing a drain valve or a fitting thread. | The joint is a union or compression fitting; those don’t seal on the thread. |
| Resideo L1 CHW3610W8001 | Wi-Fi app alerts, 5 ft cable sensor, freeze and humidity alerts, 3 AA batteries | You want a phone alert when water hits the floor around the heater. | You don’t have Wi-Fi at the heater’s location. |
Camco’s catalog lists the 11523 as the carded plastic water heater drain valve, 3/4 in. NPT × 3/4 in. male hose thread and 2-1/2 in. long. Camco also sells a brass version with the same thread and length. Measure the old valve’s shank before you buy, because Camco sells 3 in. and 4-3/8 in. versions for tanks with deeper ports.
RectorSeal’s data sheet lists T Plus 2 for hot water to 203°F and calls it non-toxic under NSF Standard 61. A. O. Smith’s fix for a leaking thread is pipe dope or Teflon tape on the threads, and T Plus 2 is the pipe dope. For the difference between tape and dope, see Teflon tape vs pipe dope vs putty.
The Resideo L1 is in the kit because A. O. Smith’s manuals recommend an automatic leak detector near the heater. If you’d rather compare more of them, the water leak detector guide covers others.
When the drain valve is dripping
It’s the most common bottom leak and the easiest to fix. Start with the simplest step.
| Where it drips | Try this first | If that fails |
|---|---|---|
| From the spout, valve closed | Turn the handle fully closed, then cap the hose thread | Replace the valve |
| From the spout after a flush | Open and close it a few times; sediment can hold it open | Replace the valve |
| Around the handle stem | Snug the handle; plastic valves wear | Replace the valve |
| Where it threads into the tank | Drain the tank and reseal the thread | Have a plumber look at the tank port |
A drip from the spout of a closed valve usually means grit is holding the seat open. Camco’s guide notes that sediment and scale on the bottom of the tank can block the valve. Flushing pushes that grit through the valve, which is why some valves start dripping right after a flush.
A hose cap on the spout is a fine stopgap. It doesn’t fix the valve, but it keeps a slow drip off the floor until you have time to swap it.
My call on plastic versus brass: the plastic valve is what most heaters ship with, and it’s fine for most homes. A brass valve with the same thread is worth it if you flush the tank often, because the handle takes the wear.
Replace a water heater drain valve
Built on A. O. Smith’s draining steps. The tank must be empty or close to it before the old valve comes out.
- 1Shut it down
Gas control to OFF and close the gas supply valve, or turn the breaker off on an electric heater.
- 2Let the water cool
A. O. Smith has you run a hot faucet until the water runs cool before draining, to cut the risk of scalding.
- 3Close the cold water valve
Then open a hot water faucet in the house so air can get in and the tank drains faster.
- 4Drain through a hose
Connect a garden hose to the old valve and run it to a floor drain or outside. If sediment blocks it, the manual says to contact a qualified person.
- 5Unscrew the old valve
Turn it counterclockwise with a wrench on the body. Have a bucket ready for the last of the water.
- 6Seal and thread the new one
Brush T Plus 2 on the new valve’s male threads, thread it in by hand, then snug it with the spout pointing down.
- 7Refill before you heat
Close the new valve, open the cold supply and leave a hot faucet open until water runs without air. Then check the new valve for drips.
- 8Turn it back on
Relight or turn the breaker on only after the tank is full. An electric element in an empty tank burns out, as Camco’s guide warns.
Plastic valves crack if they’re cranked down hard. Snug is enough when the threads are sealed.
Water from the relief valve pipe
The temperature and pressure relief valve has a pipe that runs down the side and ends near the floor. Water there means the valve opened.
| What you see | Likely cause (A. O. Smith) | What to do |
|---|---|---|
| Small drips, often after the heater runs | Thermal expansion | Add or check an expansion tank |
| Steady drip at all times | Water pressure too high | Test pressure; a pressure reducing valve set to 50 to 60 psi |
| Drips with good pressure and an expansion tank | Debris on the seat, or a worn valve | Flush it once by lifting the lever, then replace if it still drips |
| Large amounts of very hot water | Overheating | Turn the gas off and call a qualified person |
Camco’s guide says the relief valve is set to open at 150 psi or 210°F, and that a valve that leaks or opens within normal temperatures should be replaced. Before you replace it, test the house pressure with a hose-thread gauge. If the pressure is high, a new valve will drip too.
The gas manual’s warning is worth repeating: never cap or plug the relief valve or its pipe, and never run the heater without a working one. The water heater expansion tank guide sizes a tank, the water pressure gauge guide covers the test, and T&P relief valve replacement by size matches a new valve to your heater.
Leaks from above that end up on the floor
A fitting on top can leak for weeks before anyone looks up.
Check the cold inlet, the hot outlet and the relief valve where each one threads into the tank. A. O. Smith’s cotton swab test works on all three. If a swab comes out wet, the manual’s fix is to drain the tank, remove the fitting, put pipe dope or Teflon tape on the threads and put it back.
Connectors can leak too. Camco’s guide explains that copper piping on a steel tank needs dielectric fittings, because galvanic corrosion of the threads will cause leaking. Green or white crust on a connection is a sign of that slow leak.
A cold inlet pipe can also sweat. A. O. Smith notes condensation and dripping on pipes when the water temperature is low in humid weather. That water runs down the outside of the jacket and lands at the base.
Is it condensation? Gas heaters after lighting
A gas heater can make its own water when the tank is cold. A. O. Smith says this is normal and goes away.
| Sign | Condensation | A real leak |
|---|---|---|
| When it shows up | When first lit, or after a big draw of cold water | Any time, hot or cold |
| What you hear | Dripping or sizzling on the burner | Nothing, or a steady drip |
| How much | A small puddle | Keeps growing |
| What happens next | Stops once the tank reaches temperature | Doesn’t stop |
The burner heats a cold tank, and the water vapor in the flue gas condenses on the cold steel and drips back down. A. O. Smith’s gas manual says you may hear drips or sizzling and see a small puddle, and that it isn’t a leak. If the floor is still wet a day after the tank is fully hot, stop calling it condensation and keep looking.
A. O. Smith also lists water on the side of the tank from condensation when the panel or insulation isn’t in place. Check that the burner door and covers are on.
When the tank itself is leaking
A steel tank that’s rusted through can’t be patched. It needs a new heater.
A. O. Smith’s electric manual says it plainly: because of the normal corrosive action of water, the tank will eventually leak. The anode rod slows that down by corroding first, as Camco’s guide explains, but it doesn’t stop it forever.
Signs it’s the tank: every fitting and valve is dry after the swab test, water seeps from under the jacket, and it comes back every time you dry it. Rusty water in the pan points the same way.
My call: once you’ve confirmed a tank leak, don’t wait for it to get worse. Shut it down if the leak is growing, and plan the replacement. The best water heater guide covers replacements, how to replace a water heater walks the job, and water heater repair cost helps you price it.
| Question | Answer |
|---|---|
| Can a tank leak be sealed? | No. The tank is lined steel; a leak means it has rusted through |
| Will it get worse? | Expect it to. Shut it down if it grows |
| Is the warranty worth checking? | Yes. The tank warranty length is on the heater’s label and in its manual |
| Does an anode rod stop it? | Only slows corrosion; it doesn’t fix a leak |
Catch the next leak before it soaks the floor
A. O. Smith’s manuals recommend two things under and around a heater: a pan and a leak detector.
| Protection | What the maker says |
|---|---|
| Drain pan | Gas heaters: a metal pan at least 2 in. wider than the heater, piped to a drain, water limited to 1-3/4 in. deep |
| Leak detector | Install an automatic leak detection device; some also shut off the water supply |
| Inspection | Check the pan, pipes and area around the heater regularly and fix leaks found |
Resideo’s guide says to set the detector flat on the floor, or hang it on the wall and run the cable along the floor. It can take up to a minute to sense a leak, then it alerts the phone app. For pan sizes and drain fittings, see water heater drain pan.
My call: put the detector or its cable where water would run first, at the low side of the pan or the floor. A sensor on the high side stays dry while the floor gets wet.
Mistakes that cost money
| Mistake | Why it hurts |
|---|---|
| Replacing the heater before checking fittings | A. O. Smith says most suspected leakers aren’t leaking tanks |
| Capping the relief valve pipe | The gas manual warns it could cause an explosion |
| Turning on an electric heater before it’s full | Camco warns the element can burn out |
| Cranking a plastic drain valve tight | It cracks and leaks worse |
| Calling it condensation for weeks | Real condensation stops once the tank is hot |
| Draining while the water is still hot | A. O. Smith has you run the water cool first to avoid scalding |
When to call a licensed plumber
The relief valve is dumping hot water
Turn the gas off and call. That’s the maker’s instruction.
You smell gas
Leave the house and call the gas utility from outside.
The drain valve threads are leaking
A rusted tank port may not take a new valve.
The tank is leaking
Gas, venting and code work come with the replacement.
Questions people ask
Should I turn off my water heater if it’s leaking from the bottom?
If it’s leaking faster than a slow drip, yes. Turn the gas control to OFF or turn off the breaker, then close the cold water valve on top. A slow drip from the drain valve can wait while you find the source.
Can a water heater leaking from the bottom be fixed?
Often, yes. A drain valve, a leaking thread or a relief valve can be fixed. Water seeping from the tank itself can’t; the heater needs replacing.
How long will a water heater last once it starts leaking?
No maker gives a number. A fitting leak doesn’t shorten the tank’s life once it’s fixed. A tank leak means the steel has rusted through, and it can grow without warning, so plan the replacement.
Can I take a shower if my water heater is leaking?
If the leak is a small drip from a valve or fitting, the heater still works. If you’ve shut it down for a tank leak or a relief valve dumping hot water, leave it off until it’s repaired.
Why is there water under my gas water heater but no leak?
It can be condensation. A. O. Smith says a cold tank can make water that drips onto the burner and leaves a small puddle, and that it stops once the tank reaches temperature.
Why does my water heater drain valve keep dripping?
Usually sediment holding the seat open or a worn plastic valve. Open and close it a few times, cap the spout, and replace the valve if it still drips.
How much does it cost to fix a leaking water heater?
It depends on the source: a drain valve or relief valve is a small part, while a tank leak means a new heater. The water heater repair cost guide gives ranges.
How I put this together
Why trust me
I’m Isaac Daniels, a licensed journeyman plumber in Georgia (license #JP507711). I’ve used every part in the kit. The checks and steps come from A. O. Smith’s manuals, Camco’s water heater guide and catalog, RectorSeal’s data sheet and Resideo’s installation guide, read on Oct 22, 2026.
How I pick
- One part for each common bottom leak: the drain valve, a leaking thread and the next leak.
- Real brands with maker documents that match the listing’s model number.
- New and in stock on Amazon on the day of the update.
- No scores: each part does a different job, so they’re listed as a kit.
- Prices come from Amazon’s API with the time they were read.
Sources
- A. O. Smith, Residential Gas Water Heater Installation Instructions and Use & Care Guide, 100400765.
- A. O. Smith, Residential Electric Water Heater Installation Instructions and Use & Care Guide, 100341465 (March 2021).
- A. O. Smith, water heater manual 185834-000, “Leakage checkpoints.”
- Camco, Residential Water Heater Construction guide (camco.net catalogs).
- Camco, Plumbing and Hardware catalog 72001, water heater drain valves 11512, 11513, 11522, 11523.
- RectorSeal, T Plus 2 pipe thread sealant product data sheet.
- Resideo, Wi-Fi Water Leak and Freeze Detector installation guide 33-00381 (CHW3610W).