No Hot Water: What to Check, in the Right Order

Step 1: Confirm it's the heater, not the tap

Run hot water at two fixtures on different floors and give each a full minute. A single fixture with no hot water is usually a cartridge, a stop valve or a crossed connection — not the water heater at all.

• One fixture affected: suspect the fixture or its shutoff
• Whole house affected: suspect the water heater or its supply
• Hot at first, then cold within minutes: suspect capacity, a dip tube or a failed lower element

Step 2 (electric): power, breaker, reset

Electric units lose hot water when they lose power or when a high-limit switch trips. Check the breaker labeled for the water heater. If it has tripped, reset it once. If it trips again, stop — a repeat trip means a shorted element or wiring fault that needs a technician.

• Breaker off or tripped: reset once only
• Red reset button on the upper thermostat: press once if it has popped
• Trips again immediately: stop and call — this is an electrical fault

Step 3 (gas): pilot, thermocouple, gas supply

On a gas unit, no hot water usually means the burner is not firing. Check that the gas shutoff at the unit is open and that other gas appliances still work. If the pilot is out, follow the lighting instructions on the unit's own label — and only if you are comfortable doing so.

• Other gas appliances also dead: it's a supply issue, call the utility
• Pilot lights but will not stay lit: usually a failing thermocouple
• No ignition attempt at all: control valve or igniter, needs a technician

Step 4: Look for the signs that change the answer

Some symptoms take the DIY options off the table entirely. If you see any of these, shut the unit down and call rather than continuing to troubleshoot.

• Water pooling under the tank body
• Rust-colored water from hot taps only
• Rumbling or popping from the tank, which indicates heavy sediment
• Water discharging from the temperature and pressure relief line
• A unit older than roughly 10–12 years with a new failure

Step 5: How to shut it down safely

If you need to stop the unit before help arrives: close the cold-water inlet valve at the top of the tank, then remove power — gas valve to OFF for gas units, breaker to OFF for electric. Leave the tank full unless it is actively flooding the space.