Water heater not working? Start here.

Why do I have no hot water at all?

No hot water anywhere in the house is usually a failed ignition or heating component — not a failed tank.

On a gas heater, the usual suspects are a pilot that has gone out, a burned-out thermocouple that no longer proves the flame, or a failed gas control valve. On an electric heater, it is normally a tripped breaker, a tripped high-limit safety switch, or a failed upper heating element. A tank that is stone cold is rarely a tank that has failed — the steel is usually fine and the part that lights it is not.

• Check the breaker for the water heater, and reset it once if it has tripped. If it trips again, stop and call.
• Confirm other gas appliances still work — if the stove is dead too, the problem is the gas supply, not the heater.
• Look at the temperature dial. Dials get knocked down by boxes, vacuum cleaners and house guests more often than you would think.

Why is there not enough hot water for my household?

If the hot water has never quite been enough, the tank is usually undersized for how your household actually uses water, rather than broken.

Capacity is measured by first-hour rating — how much hot water a unit can actually deliver in the first hour of heavy use — not by the gallon number printed on the label. A 50-gallon tank that recovers slowly can deliver less usable hot water than a smaller tank that recovers fast. On top of that, mineral scale settles in the bottom of the tank and takes up real volume, so a heater that was correctly sized eight years ago may not be today.

• Has it always been this way, or did it get worse gradually? Always means sizing. Gradually means scale.
• Count how many fixtures run at the same time on a normal morning.
• Has the household changed — someone moved in, a soaking tub went in, the house started taking guests?

Why is my hot water not hot enough?

Lukewarm water at every tap is usually a thermostat problem, a failed heating element, or cold water bleeding into the hot line through a failed mixing valve.

On an electric heater, a dead lower element leaves you with a short burst of hot water and then tepid. On gas, a hardened layer of scale sitting between the burner flame and the water acts as insulation and stops the tank ever reaching temperature. And a single-lever valve or shower cartridge that has failed internally will quietly push cold water backwards into the hot line, which makes every tap in the house lukewarm and has nothing to do with the heater at all.

Set the thermostat to 120°F. That is hot enough to keep the tank healthy and low enough to limit scald risk — a meaningful margin if there are children or older adults in the house.

• Run a hot tap for two minutes, then measure it with a kitchen thermometer. A real number is worth ten minutes of guessing.
• Check the dial setting on the heater before anything else.
• Did this start right after a faucet or shower valve was worked on? That points away from the heater.

Why is my hot water rusty or brown?

Discoloured water on the hot side only means corrosion inside the water heater, and it is the clearest early warning that a steel tank is nearing the end of its life.

Every tank has a sacrificial anode rod in it, which corrodes on purpose so the steel does not. When the rod is spent, the tank starts giving itself up instead. Caught early, that is a repair — a new anode rod, or a corroded nipple replaced. Once the tank wall itself is rusting through, there is no repair; a steel tank cannot be patched or relined, and anyone who offers to is selling you a delay.

• Run cold into a white cup, then hot, and compare. If both are discoloured, it is the supply line, not the heater.
• Check whether it clears after running for a minute, or stays discoloured throughout.
• Note where the heater sits. Upstairs or over finished space raises the cost of guessing wrong.

Why does my hot water smell like rotten eggs?

A rotten-egg smell in the water is hydrogen sulfide, produced by harmless bacteria reacting with the magnesium anode rod inside the tank — most common on well water.

It is a repair, and usually a straightforward one: a different anode rod material plus a sanitising flush of the tank normally clears it. The smell is unpleasant rather than dangerous.

The distinction that matters: a rotten-egg or sulfur smell in the air is not this. That is the odorant deliberately added to natural gas and propane so that leaks can be smelled. If you smell it in the room rather than in the water, leave the building and call 911 or your gas utility from outside — see the box above.

• Smell the cold tap too. Both sides means the source, not the heater.
• Carry a glass of the hot water outside and smell it there — a nose adjusts fast in a small room.
• Are you on a well? That makes this the likeliest explanation by a wide margin.

Why is my water heater rumbling or popping?

Rumbling and popping is water boiling underneath a layer of hardened mineral scale on the bottom of the tank, and it is the most common noise complaint in this area.

Sedona and the Verde Valley run mineral-heavy water. Scale drops out of it and bakes onto the tank floor, water gets trapped beneath that crust, flashes to steam and forces its way out — which is the popping you hear. Early on, a flush genuinely helps. Once the layer has hardened, it usually will not flush out, and the noise becomes an honest indicator that the tank is running hot, running inefficient, and heading toward the end of its service life. This is the mechanism behind the local rule of thumb that heaters here last 6–8 years rather than the 10–12 the manufacturer's chart assumes.

• Photograph the rating plate on the side of the unit. The serial number normally encodes the build date — send us the photo and we can tell you how old it is.
• Note when the noise happens. During or just after a heating cycle fits scale.
• Has it been flushed before? If never, and the tank is young, a flush is worth doing.

Why is there water around the base of my water heater?

Water at the base is either a leaking fitting or valve — which is repairable — or a perforated tank, which is not.

Where the water comes from tells you which. A wet discharge pipe running down to the floor points at the relief valve, and that is a pressure problem worth solving properly (see below). A wet connection at the top points at a fitting or a supply flex line. Water seeping from under the jacket with no visible source above it means the tank itself has gone, and a steel tank cannot be patched.

This is the one symptom on this page where waiting costs money rather than comfort. Tanks rarely fail politely: they weep for a while, then let go all at once.

• Dry everything completely, lay paper towel around the base and under each connection, and look again in an hour. That one test usually finds it.
• Rule out water that has tracked across the floor from an air-conditioning condensate line or a nearby appliance.
• Find the cold supply valve on top of the heater now, while it is calm, so you can shut it in seconds later.

Why won't my pilot light stay lit?

A pilot that lights and then dies is usually a failed thermocouple — one of the least expensive parts on the whole heater — or an air intake screen at the base clogged with dust and lint.

The thermocouple's job is to sense the pilot flame and hold the gas valve open; when it weakens, the valve closes and the flame goes out. On modern sealed-combustion units, the flame arrestor screen around the bottom of the heater pulls in combustion air, and a garage full of dust, lint or pet hair will choke it until the burner cannot stay lit. The other two causes are a failed gas control valve and a vent that is backdrafting — and backdrafting matters, because it means combustion gases are spilling into the room instead of going up the flue.

Do not relight it over and over. Each failed attempt puts unburned gas into the combustion chamber.

• Look at the screen at the base of the heater for dust and lint, and clear anything stored against the unit.
• Confirm the gas is on elsewhere in the house.
• Do not open the burner compartment. That is where the homeowner checks stop.

Why is my T&P valve dripping?

A dripping temperature and pressure relief valve is almost never a faulty valve — it is the valve doing precisely its job because pressure or temperature in the system is too high.

The usual cause is thermal expansion in a closed system. If your house has a pressure-reducing valve or a check valve at the meter, water that expands as it heats has nowhere to go back to, so pressure climbs on every heating cycle until the relief valve weeps it off. The correct fix is an expansion tank pre-charged to the measured static pressure of your house — not a guessed pre-charge, and not a new relief valve. This is why a relief valve that has been replaced twice still drips: the valve was never the problem.

The other causes are house pressure above the 80 psi code limit, and a thermostat set or stuck too high.

• Never cap, plug or block the discharge pipe. That valve is the only thing between a pressure build-up and a ruptured tank.
• Screw an inexpensive pressure gauge onto an outdoor hose bibb and read the static pressure. Over 80 psi is over the code limit.
• Note whether it drips during a heating cycle — that is the signature of thermal expansion.

Why does my hot water run out too fast?

Hot water that used to last and now runs out early points to a broken dip tube, a failed lower element, sediment in the tank, or cold water crossing into the hot line.

The dip tube is the plastic tube that carries incoming cold water down to the bottom of the tank so it heats before it reaches the outlet. When it cracks or breaks off, cold water is delivered straight to the top and mixes into the hot outlet — the tank is full and working, and you still get five minutes of hot water. On electric units, a dead lower element produces the same complaint. And a failed valve or shower cartridge anywhere in the house can let cold cross into the hot line, which mimics all of the above.

• Time it. Shut everything off, run one hot tap, and note the minutes until it turns lukewarm. Bring that number to the call.
• Shut the cold supply valve to the heater and open a hot tap. If it runs indefinitely, cold is crossing into the hot line somewhere.
• Did it change suddenly or gradually? Sudden fits a dip tube or an element; gradual fits sediment.

Why do my pipes bang when the hot water shuts off?

A bang when a tap or an appliance shuts off is water hammer — a pressure wave with nowhere to go — and it usually points at house pressure rather than at the water heater itself.

It earns a place on this list for two reasons. First, the same closed system and high static pressure that make a relief valve drip also make pipes hammer, so the two symptoms often share one cause and one fix. Second, banging that started right after a water heater was installed usually means an expansion tank was skipped, or fitted without setting its pre-charge to the actual pressure of the house. A softer ticking or knocking as pipes warm and move against framing is a different thing entirely, and it is normal.

• Identify which fixture triggers it, and whether it only happens on the hot side.
• Did it start after new work was done? Say so when you call — it narrows this to one afternoon's diagnosis.
• Read the static pressure at a hose bibb, same as for a dripping relief valve.