Written & reviewed by Marcus ReedIICRC WRT
Reviewed September 4, 2026· Next review Mar 2027
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.
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A leaking water heater is two problems: the appliance (plumber) and the water that already escaped (restoration). The shut-off order, the calls, and when a wet slab or subfloor needs more than towels.
The Short 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.
What This Page Covers
Puddle under the tank, drip from the relief valve, or a burst heater flooding the utility room — who to call for each case, the two shut-offs that stop it now, and when the floor needs professional drying.
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(888) 840-6512Mold can establish within 24–48 hours of water exposure — drying started today stays a drying job.
- Describe the damage & give your ZIP
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If Water Is Still Coming In
Stop the water at the fixture valve or the main, cut power to wet rooms at the breaker if you can reach the panel safely, move what you can out of the water, and photograph everything before it is touched. Water that has reached carpet pad, drywall or a subfloor is a same-day restoration call rather than a cleanup: mold can establish on wet materials within 24–48 hours, and every hour of delay moves materials from "dry it" to "replace it."
Before You Sign Anything
Ask for a written scope and the pricing basis, who is fixing the water source and when, and what the moisture readings are — a company that does not take readings is not drying. Sudden, accidental water damage (a burst pipe, a failed supply line, an appliance leak) is usually covered by homeowners insurance; long-term leaks, neglected maintenance and rising outside water usually are not. Document first, then call the restoration company, then the insurer.
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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.
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.
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