Quick answer
Find where the water is coming from: a fitting, the relief valve, the drain valve, condensation or the tank itself. Right away, turn off power at the breaker (electric) and close the cold water supply valve. A leak from the base of the tank usually means replacement. If you smell gas, leave and call 911.
Safety first
A water heater combines hot water under pressure with electricity or gas. If you smell gas, do not investigate. Puget Sound Energy says to leave the area right away, call 911 or the gas utility from outside, and avoid anything that could cause a spark, including flipping switches. Pyper Plumbing does not do gas line work, so a gas smell is a call to 911 and your gas utility first.
Also treat water around the heater with care, since it may be hot, and do not remove electrical access panels while the power is on.
Where the water is coming from
A. O. Smith, a water heater manufacturer, describes the leak location as a clue to the cause.
- Top of the heater, at the pipe connections: loose fittings are common, since expansion and normal wear can loosen them. Tightening may fix it, but overtightening can damage the fitting.
- Side, at the temperature and pressure (T&P) relief valve: this usually means the tank has seen excess temperature or pressure.
- Near the bottom, at the drain valve: a loose valve can be tightened, and one that will not close properly usually needs replacing.
- Electric models: the heating element gaskets can leak and are replaced as a repair. On gas models, A. O. Smith also lists the gas valve connection as a possible spot, which is work for a qualified technician.
- Base of the tank: often the first sign of serious internal trouble, such as a corroded tank.
Rule out condensation first
Condensation is often mistaken for a leak. A. O. Smith explains that it can appear after a long draw of hot water or when cold water first enters the tank, and that on gas models it can show up when the burner fires after sitting idle. It should stop once the tank warms, and the company's bulletin gives about 110 degrees Fahrenheit as the point where it should stop. Water that keeps appearing, or that grows, is not condensation.
What to do right now
A. O. Smith's guidance is to cut off the energy and the water before inspecting anything. Do not work on a unit that is still energized or connected to water.
- Electric heater: switch off the breaker at the electrical panel. Montana State University Extension also advises cutting power at the breaker or fuse box before removing electric access panels.
- Gas heater: close the gas shutoff valve only if you are confident doing so. If you smell gas at any point, leave and call 911.
- Close the dedicated shutoff valve on the cold water line that feeds the heater.
- Keep people and belongings away from the water, and do not run the heater until it has been checked.
- Call a plumber if the leak is anything beyond a drip you can clearly trace to a loose connection.
A leaking relief valve is a warning, not a nuisance
The International Code Council says that if a water heater works properly, system pressure is within code limits and the valve is in good condition, the relief valve should not discharge. Discharge points to a problem in the plumbing system, the heater, or the valve itself.
A. O. Smith's technical bulletin gives several possible causes. Occasional weeping can come from thermal expansion in a closed system, where pressure rises as water heats. Large volumes of hot water released irregularly mean the stored water exceeded its temperature rating, which the bulletin attributes to a malfunctioning thermostat. A separate A. O. Smith page says that if high pressure is the cause, lowering the thermostat may stop the leak while a properly sized and charged expansion tank is the lasting fix, and another bulletin says to compare supply pressure with the valve rating.
Never cap, plug or add a valve to the relief discharge pipe. The ICC warns that a closed valve or extra connection could create a dangerous condition. Montana State University Extension recommends checking the relief valve annually.
When a leak means replacement
A. O. Smith says a leak at the base of the tank is a sign to replace the unit, and that a cracked tank typically needs full replacement. The company's bulletin states that if a tank is confirmed to leak, it should be replaced. Leaks from valves, loose connectors or thermal expansion may be fixable by tightening or replacing those parts.
Age matters too, and sources do not fully agree. One A. O. Smith page says water heaters generally last 8 to 20 years depending on type. Another says average life expectancy is about 8 to 12 years and that replacement becomes more likely past 10 years, especially with a leak. Factors it names include water quality, installation and maintenance.
Sediment and hard water speed up the damage. The company says minerals settling at the bottom can cause overheating, cracks and bottom leaks, and that the sacrificial anode rod, which protects the tank from rust, typically lasts 3 to 5 years. Regular flushing and a pressure-reducing valve or expansion tank where needed can help, but they cannot repair a tank that has already corroded through.
Why you should not ignore a leak
A. O. Smith says even small leaks can cause major water damage to floors and walls and lead to mold growth, and that a leak can point to failing components that worsen quickly. Warning signs it lists include rumbling, popping or cracking sounds from sediment, rust or cloudy water, slow heating and rising energy bills. It also says leaks can worsen quickly and lead to total system failure.
When to call Pyper Plumbing
Call if the water is coming from the tank body or base, the relief valve is discharging, the drain valve will not close, a fitting keeps weeping after you tighten it, or the heater is more than about a decade old and leaking. Pyper Plumbing handles water heater repair and replacement and emergency plumbing across Snohomish, Skagit, Whatcom and Island counties.
If water is spreading, shut off the cold supply and the power first, then call. For a gas smell, leave first and call 911 or your gas utility. We can help once the area is safe, but we do not work on gas lines.
Common questions
Is a leaking water heater an emergency?
Treat it as urgent. A. O. Smith advises against continuing to use a leaking unit because even small leaks can cause major damage. Shut off power and the cold water supply, and have it checked.
Why is water dripping from the pipe on my water heater?
That is likely the relief valve discharge pipe. The International Code Council says a properly working system should not discharge, so dripping points to a pressure, heater or valve problem. Never cap the pipe.
Could the water be condensation instead of a leak?
Possibly. A. O. Smith says condensation can form when cold water enters the tank or after a long hot water draw and should stop once the tank warms. If the water keeps coming or increases, treat it as a leak.
How long does a water heater last?
Sources differ. A. O. Smith pages give about 8 to 12 years as average life expectancy in one place and 8 to 20 years depending on type in another. Water quality, installation and maintenance all matter.
Sources
Facts in this guide come from the following references. Local rules and manufacturer instructions can differ, so follow your utility and your equipment manual.
- Why Is My Water Heater Leaking? (A. O. Smith)
- Technical Bulletin 52: Leaking Temperature and Pressure Relief Valve (A. O. Smith)
- Technical Bulletin 51: Puddle on the Floor (A. O. Smith)
- When to Repair or Replace Your Water Heater (A. O. Smith)
- Water Heater Safety CodeNotes (International Code Council)
- Water Heater Maintenance (Montana State University Extension)
- Detect a Gas Leak (Puget Sound Energy)
This guide is general information, not a substitute for an on-site inspection. If you smell natural gas, leave the building and call 911 or your gas utility. Pyper does not perform gas line work.
