Quick answer
Shut it down first: turn the cold-water supply valve on top of the heater clockwise, and kill the unit's power (breaker for electric, gas valve to OFF for gas). Then split the calls: a plumber replaces or repairs the heater; a water damage restoration company handles what the leak already soaked — subfloor, drywall, adjacent rooms. A slow tank leak often runs for days before it's noticed, which is exactly the moisture that grows mold behind baseboards; a certified crew's moisture meter settles in minutes whether you need drying or just a mop. Call (888) 840-6512 to reach a certified water damage restoration company in your area; the line is answered 24/7.
Press 1 for water damage or 2 for mold, then your 5-digit ZIP. The line goes quiet for about half a minute while it connects — that is normal, stay on. If it does not connect, call once more: companies taking calls change minute to minute.
Written & reviewed by Marcus ReedIICRC WRT
Reviewed September 4, 2026· Next review Mar 2027
A leaking water heater is the rare household emergency with an off switch. The tank holds 40 to 80 gallons and is connected to a supply that will refill it forever, so the first job is not deciding who to call — it is making the leak finite.
Shut It Down First
- 1Close the cold inlet. The cold-water valve sits on the pipe entering the top of the heater. Turn it clockwise until it stops. If it is seized or missing, close the house main instead.
- 2Kill the energy source. For an electric heater, switch off its breaker — an element that runs dry burns out in seconds. For gas, turn the control knob on the unit to OFF or PILOT. Do not skip this because the leak looks small.
- 3Contain the spread. Towels and a wet vacuum on the floor, a hose from the drain valve to a floor drain or outdoors if the tank itself is leaking and you want to empty it. Move anything cardboard or upholstered out of the water's path.
- 4Photograph, then make the two calls. The heater, the puddle, the wet baseboards and anything stored nearby — before you clean up.
Two Calls, Two Different Jobs
The plumber owns the heater. Where it leaks from tells you what that visit looks like. Water at the top is usually a fitting, the temperature-and-pressure relief valve or the anode port — repairable, typically $150 to $400. Water from the bottom is either the drain valve, which is repairable, or the tank itself, which is not: a tank that has rusted through is replaced. The top-versus-bottom guide walks through telling them apart.
A restoration company owns everything the water reached. That is the call people skip, because a heater leak rarely looks dramatic. But heaters live in closets, garages and basements, against drywall and on top of subfloor, and a slow tank leak often runs for days before anyone notices the floor is warm and damp. By then the water has wicked up the back of the baseboards and into the bottom of the wall.
| What you see | What it usually means |
|---|---|
| A puddle on bare concrete, nothing else wet | Mop it, run a fan, watch it. Probably no restoration job. |
| Wet carpet or pad near the heater | Pad does not dry in place. A restoration visit is worth it. |
| Baseboards swollen or drywall soft at the bottom | Water is inside the wall. This needs meters and drying. |
| A musty smell in the closet | It has been leaking longer than you think. Get it metered. |
| Heater on an upper floor or in an attic | Check the ceiling below before anything else. |
If you are not sure which row you are in, a moisture meter settles it in a few minutes, and that is what a certified crew brings. You can describe the room to whoever answers (888) 840-6512 and find out whether it sounds like a drying job or a mop job before anyone drives anywhere.
Why Small Heater Leaks Grow Mold
The water is warm, the closet is closed, and the wall is paper-faced drywall sitting on a wet bottom plate. That is close to ideal conditions. Mold can establish on wet building materials within 24 to 48 hours, and a heater that has been seeping for a week has had several of those windows. The leak being slow is what makes it expensive: nothing prompted anyone to look.
Drying, when it is needed, is unglamorous — baseboards off, small holes or a flood cut at the bottom of the wall, air movers and a dehumidifier for a few days, readings taken until the framing is back to normal. A contained residential job of that kind typically lands between $1,300 and $5,200; the restoration cost guide shows what moves it within that range.
What the restoration company does in your home
1.Finds the water you can't see
Moisture meters and a thermal camera at baseboards, under flooring and behind drywall.
2.Pulls out the standing water
Extraction first, then anything soaked that cannot be dried is removed.
3.Dries it and logs the readings
Air movers and dehumidifiers run until the meter says dry, with a log your insurer can read.
Talk to a water damage pro now
Answered 24/7 · Toll-free · no obligation
(888) 840-6512Mold can establish within 24–48 hours of water exposure — drying started today stays a drying job.
- Press 1 for water damage or 2 for mold, then your ZIP
- Stay on through the short quiet while it connects
- A local certified company explains the job and price
What Insurance Does With a Heater Leak
The pattern is consistent across most homeowners policies: the water damage from a sudden tank failure is usually covered; the heater is not, because wearing out is maintenance. The word that decides claims is "sudden". A tank that split overnight is sudden. Rust trails, mineral crust and a stained platform tell an adjuster the leak was long-running, and long-running leaks are excluded almost everywhere.
Report it promptly, keep the photographs, and keep the plumber's note on what failed — that one sentence often carries the claim. The claim checklist covers the rest.
Before You Relight or Reset Anything
Do not restore power or gas to a heater that has leaked until a plumber has looked at it, and never to a tank that is not full — electric elements fail instantly when dry. If the relief valve was the source, that valve was doing its job: something made the pressure or temperature too high, and replacing the valve without finding out what is how the next leak is scheduled.
The Short Version
Cold inlet closed, power or gas off, photos taken. The plumber fixes or replaces the heater. If the water reached carpet, drywall or a floor below, the second call is (888) 840-6512 — answered 24/7, and it connects you to a certified water damage restoration company in your area who can tell you whether there is anything to dry.
Reading to confirm what you already suspect?
Confirm it in two minutes instead — the pro on this line answers questions about YOUR situation all day: what it is, what it should cost, whether you even need service. If you want, they'll set the appointment on the same call.
Toll-free · no obligation · asking costs nothing
Frequently Asked Questions
- 1drip contained to the pan or a valve — plumber only
- 2water reached flooring, drywall or the room next door — restoration first for extraction and drying, plumber for the tank
- 3tank burst with active flooding — shut the supply and power, then a restoration line that answers 24/7, since standing water is the time-critical half.
- 1the cold inlet valve on top of the tank — turn clockwise until it stops; if it won't turn, use the home's main shut-off
- 2power — flip the heater's breaker for electric, or rotate the gas control to OFF for gas. Don't drain the tank yourself while it's hot.
Who do I call for a leaking water heater — plumber or restoration?
Depends what's wet:
How do I shut off a leaking water heater?
Two moves:
Is water heater leak damage covered by insurance?
The sudden failure and resulting water damage — typically yes; the worn-out heater itself — usually no, that's maintenance. A slow leak the adjuster judges 'long-term' can be contested with drying documentation, which is one more reason to have the moisture readings on paper.
The leak looks small — do I really need professional drying?
Small on the surface can be large underneath: heaters sit on slabs, wood platforms or closets that wick water under adjacent walls. If moisture has reached drywall, baseboard or subfloor beyond the pan, measured drying beats guessing — the 24–48 hour mold window applies to the hidden wet, not the visible puddle.
How much does the water cleanup part cost?
Scope-dependent — a contained utility-closet dry-out is a small job; a burst tank that ran across a finished basement is not. The pro quotes your exact situation on the call, costs explained before any work starts, and mitigation is priced separately from the plumber's tank replacement.
What happens when I call a restoration line about a heater leak?
You describe where the tank sits, what's wet and for how long — a certified local pro gives an arrival window, tells you whether readings justify drying equipment, and can coordinate alongside your plumber's tank swap.
Who do I call right now for water damage?
Call (888) 840-6512. The line is answered 24 hours a day, seven days a week, and connects you with an IICRC-certified water damage restoration company that serves your area. A recorded menu picks up first: choose water damage or mold, key in your 5-digit ZIP code, and hold through the short silence while the call is passed to the company.
Describe what you can see — where the water is coming from, how long it has been there, and whether it smells — the more specific you are, the faster the right company is on the line. If the source is a pipe or an appliance, shut the main water valve first. Have four things ready and the call goes quickly: the address, when the water started, what is wet now, and whether you have filed an insurance claim.
Still not sure which of these is your situation? (888) 840-6512 · toll-free · answered 24/7
Sources
- IICRC S500 Standard for Professional Water Damage Restoration
- III — Water damage and homeowners insurance
Methodology: How we source and verify data · Report an error
Disclaimer: HearthDry is an independent educational resource. This article is for informational purposes only and does not constitute professional, legal, or insurance advice. Consult licensed professionals before making decisions about your property or insurance claims.