You turn the shower on, wait the usual 30 seconds for it to warm up, and... it doesn't. Cold water only. No hot water from any tap in the house. Before you call a plumber, there are six things you can check yourself in the next ten minutes that solve roughly 60% of "no hot water" calls. Here is what to look at, in the order most likely to be your problem, and what each fix costs if you do need a pro.
Is It a Gas or Electric Water Heater?
How you troubleshoot depends on which kind you have. Look at the unit:
Gas water heater: Has a black gas line connected to it (usually with a yellow valve handle), a vent pipe going up to the ceiling, and a control valve at the bottom front of the tank with words like "PILOT," "ON," and "OFF."
Electric water heater: No gas line, no vent pipe. Has a thick electrical conduit going into the top or side, and one or two metal access panels on the front of the tank.
Tankless water heater: A flat box mounted on a wall, much smaller than a tank unit. Often has a digital display.
The 6 Things to Check (Gas or Electric Tank)
### 1. Is the Breaker Tripped? (Electric Only)
Walk to your electrical panel. Find the breaker labeled "water heater" — it is usually a double-pole 30-amp breaker (two breakers tied together). If it is in the OFF position or sitting halfway between ON and OFF, it has tripped.
Flip it fully to OFF, then back to ON. If it stays on and the water heats up over the next hour, you are done. If it trips again immediately or within a few hours, do not keep resetting it — there is an electrical issue (usually a failed heating element or thermostat) and resetting a tripping breaker can cause damage. Call a pro.
### 2. Is the Pilot Light Out? (Gas Only)
On older gas water heaters with a standing pilot, look at the bottom of the tank. There is often a small window where you can see if the pilot flame is lit. No flame = no heat.
Most modern gas heaters have a relight procedure on a sticker on the front. The general process: turn the gas control to OFF, wait 5 minutes for residual gas to clear, set the temperature dial to the lowest setting, then follow the relight procedure (usually press the pilot button while clicking the igniter). If it lights and stays lit, turn the control to ON and set the temp.
If the pilot will not stay lit after multiple tries, the thermocouple has failed (a $150–$250 repair) or the gas valve has failed (a $300–$500 repair). Both are professional jobs.
Note: Most water heaters made after 2010 do not have a standing pilot. They use electronic ignition. If you do not see a pilot window or a manual igniter, this step does not apply to your unit.
### 3. Is the Gas Supply On? (Gas Only)
Find the gas line going into the water heater. There is a shutoff valve on it — a yellow lever or handle. The valve is OPEN when the handle is parallel to the pipe and CLOSED when perpendicular. If someone recently worked on the gas line or you had work done in the house, the valve might have been turned off and not turned back on.
Also check whether other gas appliances in the house are working — your gas stove, gas dryer, or gas furnace. If none of them work, the gas is off at the meter (call your utility company), or you have a regional outage.
### 4. Has the Thermostat Drifted? (Both Types)
On gas heaters, the temperature dial is on the front of the gas control valve. On electric heaters, the thermostats are behind the access panels (and there are two of them — upper and lower).
If the dial got bumped down to "VACATION" or near the lowest setting, the heater will not produce hot water at usable temperatures. Set it to the middle range — around 120°F or the marker labeled "NORMAL" or "A."
Don't go above 130°F. Higher settings scald, accelerate scale buildup, and shorten tank life. 120°F is the standard for a reason.
### 5. Is the Tank Leaking?
Walk around the water heater and look at the floor. Is there water pooling? If yes, the tank itself may have failed — and a failing tank often loses heat through the leak. We have a full guide on diagnosing this — see our post on water heater leaking from the bottom. A confirmed tank leak means replacement, not repair.
### 6. Have You Run the Tank Dry Recently?
If you took back-to-back showers, ran the dishwasher, did laundry, and then someone tried to take a fourth shower, you may simply be out of hot water. A 40-gallon tank delivers about 25–30 gallons of usable hot water before it runs out. Recovery time is 30–60 minutes for gas, 60–90 minutes for electric.
If the system was running fine and just gave out under heavy use, wait an hour and try again. If hot water comes back, you do not have a problem — you have a sizing issue, and the next time you renovate or replace, consider a larger tank or tankless.
Tankless Troubleshooting (Different Failure Modes)
Tankless heaters fail differently than tanks. Common causes of "no hot water" on a tankless:
Error code on the display. Most tankless units show a numeric error code when something is wrong. Look it up in the owner's manual or call the manufacturer — common codes mean ignition failure, flame loss, or clogged inlet filter.
Hard water scale clogging the heat exchanger. Tankless units in Central Texas need annual descaling because of our hard water. If yours has not been descaled in 18+ months, scale is probably restricting flow through the heat exchanger and the unit cannot produce hot water at the requested rate. Descaling service is $150–$250.
Ignition or flame sensor failure. Tankless ignition is more complex than a standing pilot. Sensor failures are common and usually a $200–$400 repair.
Vent obstruction. The exhaust vent on a tankless can get blocked by a bird's nest, a wasp nest, or debris. The unit will refuse to fire as a safety measure. Visual inspection of the vent opening is a 30-second check.
What Each Fix Actually Costs
DIY (relight pilot, reset breaker, turn up thermostat): $0
Thermocouple replacement (gas): $150–$250
Heating element replacement (electric): $200–$350 (one element) / $350–$500 (both)
Thermostat replacement: $150–$300
Gas valve replacement: $300–$500
Tankless descaling: $150–$250
Tankless flame sensor / ignitor: $200–$400
Full water heater replacement: $1,200–$2,200 (tank) / $3,500–$6,000 (tankless)
When to Stop Troubleshooting and Call
If you smell gas: Stop everything. Get out of the house, leave the door open, and call your gas utility from outside. Do not flip light switches, do not light matches, do not start a car in the garage. Once the leak is confirmed and shut off at the meter, then call a plumber.
If the breaker keeps tripping: Stop resetting it. Repeated tripping can damage the wiring or cause a fire. Call a licensed plumber or electrician.
If the tank is leaking: Shut off the water supply to the tank and the power. Call us — same-day replacement available.
If you've checked everything and it's still not working: Worth a service call. Diagnostic visits run $89–$149 and are usually credited toward the repair if you proceed.
Get Hot Water Back Today
We do same-day no-hot-water service across Central Texas — Pflugerville, Bastrop, Taylor, Elgin, Georgetown, Hutto, Manor, Cameron, Rockdale, Brenham, and our full service area. Call (737) 260-7255. Texas license M-37654 (plumbing) and TACLB00027491E (HVAC). Flat-rate pricing on every repair — the quote is the price.