Emergency Plumbing → 120F and rising
A water heater leaking has four leak points and four answers, three of them repairs measured in parts and an hour of labor. One means the tank is finished. Stored water sits at 120F while you work out which.
A leak at a top connection or the drain valve is usually a small parts repair inside one labor hour. A water heater leaking from the bottom of the tank body is corroded through and can only be replaced.
With a water heater leaking, the stored water sits at 120F or hotter, and on a gas unit a failing heater can vent badly at the same time. Make it safe before you diagnose it.
Before you diagnose
The valve on the cold pipe entering the top of the tank. That stops the tank refilling as it empties through the leak.
Electric: switch off the dedicated breaker. Gas: turn the control knob to off. Do not touch the gas supply valve unless you smell gas and are leaving.
Stored water sits at 120F or hotter. Relief-valve discharge and drain-valve water can scald, so do not put a hand in the flow to find the source.
Shoot the wet area, the tank label with its age, and the leak point. Those three photographs answer half of what a plumber will ask on the phone.
“Some people even go as far as replacing the water heater only to find out that the leak is still there.”
Where is my water heater leaking from?
Top connections mean a loose fitting; a dripping relief valve means excess pressure; water from the tank body means replacement.
Water runs downhill and along surfaces, so where it pools tells you almost nothing about where it started. A puddle on the floor is equally consistent with all four sources.
A fifth possibility: the heater is not the leak. A service technician from Word of Advice TV reports calls where the source was a furnace beside it, and people replace the tank and find the leak still there.
His checklist is longer than four items: the relief valve body and outlet, the drain valve, the inlet and outlet fittings, the element gasket, the anode threads, and only then the tank.
There is a trap in the timing: metal expands with heat, so a crack widens while the unit runs. A leak that stops once the unit is off has cooled down, not healed.
Photograph the wet point and the rating plate showing the manufacture date. Age is half the repair-or-replace decision, and it is the first thing a plumber will ask.
Every ranking page lists the relief valve as a leak source. None of them explains what a dripping one actually means, and the difference matters because it is the only leak on the tank that is a symptom rather than a fault.
A temperature and pressure relief valve opens when the water exceeds its rated temperature or pressure. If it drips persistently, the usual cause is house pressure that is too high or a thermostat set too hot, not a broken valve.
Replacing the valve without fixing the pressure gets you a new valve that drips. A plumber should check static pressure and, where it is high, look at a pressure-reducing valve or an expansion tank rather than just swapping the part.
Never cap, plug or reroute the discharge pipe upward
The discharge pipe exists so a tank cannot become a pressure vessel, and capping it removes the only protection the tank has. If it drips onto something you care about, have it re-routed to a drain.
Stored water is held at 120F or above, which is hot enough to scald in seconds. Do not put a hand into a discharge stream to trace a leak, and do not lean over a relief valve that is actively venting.
The gas risk sits alongside it and gets missed while attention is on the water. A gas water heater that is failing may also be back-drafting, which puts combustion products including carbon monoxide into the room rather than up the flue.
The CPSC treats a working carbon monoxide alarm as basic equipment wherever fuel-burning appliances are installed. If yours sounds, or if anyone in the house has an unexplained headache or nausea near the unit, leave the building and call 911 or your gas utility from outside.
Know the line
Is it safe to shower while the water heater is leaking?
A short shower is usually fine if the leak is a fitting drip and the area around the tank is dry and being watched. Do not shower if water is pooling under the tank body, if the relief valve is discharging, or if there is any gas smell in the room.
The reason is mechanical rather than cautious. Drawing hot water pulls cold water into the tank, which raises internal pressure at exactly the moment the tank is least able to take it.
If the tank body is leaking, treat every draw of hot water as a small gamble. Corroded liners fail progressively and then suddenly.
Manufacturers write most of the ranking content on this query, which makes their repair-or-replace advice difficult to weigh. The rule is simpler than their guides suggest.
Two findings end it: wet insulation around a gas unit’s burner chamber, or a visible crack in the tank threads. Either means the inner tank has gone.
A component leaking at the threads - relief valve, gas valve, element, anode - points at a loose fit or a failed gasket, and that is a repair while the threads are slightly damaged.
Indicative US ranges. Always get a written quote.
| Job | Typical range | Notes |
|---|---|---|
| Emergency trip fee | $75–$500 | Charged to attend and diagnose |
| Labor, standard hours | $100–$200 / hr | Weekday business hours |
| Labor, after hours | up to $350 / hr | 1.5×–2× the base rate |
| Fitting or drain-valve repair | small parts cost + labor | Usually inside one labor hour |
| Water damage cleanup, if it flooded | $1,000–$2,000+ | Separate restoration trade |
Unit prices vary too widely by capacity and fuel for one honest figure, so what is published here is the labor side. The rest sits in our breakdown of the bill.
If water has spread across flooring, drying is a separate trade and bill. If the leak outruns the tank isolation, close the property main; our guide to the main shut-off valve covers where it is.
Emergency Services 24H is a referral service. The plumbing section covers each fixture, and the triage page settles whether this is a tonight job.
Your request routes to licensed, insured contractors covering your area, and they contact you directly to quote and schedule.
24/7 dispatch network
Tell us where the water heater is leaking from. Licensed, insured plumbers covering your area will contact you directly. No obligation to hire.
Fire, a gas smell, or an injury? Leave the building and call 911 first, then your gas utility or power company. Use this form once you are safe.
Straight answers
The questions homeowners actually search for on this problem, answered in plain language.
Browse all guidesExpect a materially larger bill than a repair: after-hours labor runs 1.5 to 2 times standard plus a trip fee. A fitting leak is parts and an hour, which is the difference worth establishing.
Only for a drip at a top fitting, watched. Water from the tank body is corrosion, and running the unit keeps it pressurised. Shut the cold inlet and the power.
For a small drip at a top fitting, yes, briefly and watched. Water from the tank body is progressive corrosion, so every hour risks a full release.
Only if the leak is from the tank itself. Inlet and outlet connections, the drain valve and the relief valve are normally repairable; water from beneath the tank body means the liner has corroded through.
Not overnight and not unattended. Shut the cold inlet, then the breaker or the gas control knob. Stored water sits at 120F or hotter, and a leaking gas unit may be venting badly.
A tank-body leak is not something to plan around: some run for days, some open within hours. Past about ten years old, treat replacement as the only option.
A short one, if the leak is a fitting drip and the area is dry. Not if water is pooling, the relief valve is discharging, or there is a gas smell.
Because it is doing its job. A T&P valve opens when temperature or pressure exceeds its rating, so a persistent drip means house pressure is too high or the thermostat too hot.
Independent, publicly published sources, quoted with attribution and linked in full. None is affiliated with Emergency Services 24H, reviewed this page, or works in the referral network.
Reviewed on . If a figure here no longer matches its source, that is a bug, so tell us and we will correct it.
24/7 dispatch network
Tell us what has failed and how soon you need someone. We route your request to licensed, insured contractors covering your area, and they contact you directly.
Fire, a gas smell, or an injury? Leave the building and call 911 first, then your gas utility or power company. Use this form once you are safe.