When your water heater is not heating, it almost always means something inside has failed — a burner that will not fire, a dead element, a tripped safety, a bad gas valve. Two causes are worth a quick look. The rest are diagnosis-and-repair work that is faster and safer in the hands of a licensed tech, especially anything touching gas or electrical.
Here is what is usually going on with a gas, electric, or tankless unit that stopped heating — and how quickly we can get your hot water back.
Jump to your unit
Quick diagnosis
Match your symptom, find the next step
First, two quick checks
Before you call · not really repairs
Flip the breaker off and back on once. If it trips again right away, stop — that is a fault inside the heater, and it is a call, not a reset.
A dial bumped down to warm, or a unit left in vacation mode, leaves you with cold water and nothing actually broken.
Not sure if yours is gas, electric, or tankless?
Quick tells: a gas unit has a burner, a pilot or igniter, and a flue/vent pipe out the top — usually in a garage or closet. An electric unit runs off a 240V breaker with no vent and has one or two access panels on the front. A tankless unit is a compact box mounted on the wall. Use the matching section below.
Gas water heater
No hot water · the burner is not firing
If the pilot will not stay lit, the thermocouple — the sensor that proves a flame to the gas valve — is usually failing. A cheap part, but it is gas work.
The pilot is fine, but the main burner never lights. The valve or its thermostat has failed and needs service.
A hard, insulating layer on the tank bottom keeps the burner from heating the water. A flush helps; heavy buildup on an older tank is a sign it is near the end.
Not sure what you have? Our rating-plate guide shows where to find your model. Anything in the gas system is diagnosed and fixed by a licensed tech — usually the same day.
Electric water heater
No hot water · element or thermostat
The most common electric failure — a dead upper element means the water never warms.
A bad thermostat will not send power to the element, even when the element itself is fine.
If the red safety button keeps tripping, that is a symptom of a deeper fault — not something to keep resetting.
Testing and swapping elements means working in a live panel and draining the tank. We carry the common parts on the truck and handle it same-day.
Skip the guesswork — we will find the real cause fast.
Licensed techs, common parts on the truck, most repairs done the same day.
Book a RepairTankless water heater
No hot water · read the error code
Almost every no-heat fault shows a code that points right at the cause. Look yours up in our error code guide, or your brand page — Rinnai, Navien, Noritz.
Tankless units need strong gas volume and clear venting to fire — a whole family of codes points straight here.
Hard-water scale chokes the heat exchanger and cuts output. A descale clears it.
The fix behind the code is technician work. We service every major tankless brand and can usually clear it fast.
Some hot water, just not enough
Lukewarm, or running out fast
The heater is working but falling behind — a failing element, sediment, a cracked dip tube letting cold water short-circuit to the top of the tank, or simply a unit that is too small for how the household has grown. Sorting out which one takes a proper diagnosis.
If capacity is the real problem, we will walk you through the right size or adding capacity with a mixing valve — and if the unit is on its way out, here are the signs it is time to replace.
Smell gas, or seeing water on the floor? Do not flip switches or relight anything. If you smell rotten eggs or sulfur, leave the house and call your gas utility or 911 from outside. A gas smell, a leaking tank, or a breaker that keeps tripping all mean it is time to call a pro right now — not to keep troubleshooting.
How to shut it down safely
If you need to stop it before help arrives: on a gas unit, turn the gas control knob to OFF; on an electric unit, switch off its breaker at the panel. Then close the cold-water supply valve on the pipe entering the top of the tank. That isolates the heater without touching anything you should not.
Why this one is worth a call
Gas · electric · water · pressure
A water heater not heating is rarely a safe DIY fix — it brings together gas, electricity, water, and pressure, the four things you least want to guess with. A wrong move can void the warranty, flag a code violation, or turn a small part into a much bigger repair.
Our licensed, permitted techs find the real cause the first time, carry the common parts on the truck, and get most repairs done the same day. Book before noon and there is a good chance you will have hot water again tonight. Serving homeowners across Oregon, Washington, and California.
Repair or replace — and the cost
A straight answer, not a sales pitch
A failed part on a unit under about ten years old is usually worth repairing — an element, thermostat, thermocouple, or valve costs a fraction of a new heater. Past ten to twelve years, or once the tank itself has gone, replacement is the smarter money.
What drives the price: fuel type (gas or electric), tank versus tankless, capacity, and whether code upgrades or venting changes are needed. We give you the repair-or-replace call up front — see typical replacement costs, or the signs it is time to replace.
Common questions
No hot water, answered
Why did I suddenly lose all my hot water?
Something in the heat path failed at once — a tripped breaker or dead element on an electric unit, a pilot that went out or a bad gas valve on a gas unit, or a fault behind an error code on a tankless. A quick check tells you which; the fix is usually a licensed-tech job.
Is no hot water an emergency?
On its own, no — it is an inconvenience. But paired with a gas smell, a leaking tank, or a breaker that keeps tripping, treat it as urgent and call right away.
Can I fix a water heater with no hot water myself?
You can safely reset a breaker once, relight a pilot per the tank label, or nudge the thermostat. Anything past that — elements, thermostats, gas valves, thermocouples, venting — means working with live electrical or gas and is a job for a licensed tech.
How long does a water heater repair take?
Most no-hot-water repairs are same-day. Our techs carry the common parts — elements, thermocouples, valves — on the truck, so booking before noon usually means hot water again by evening.
Should I repair it or replace it?
A failed part on a unit under about ten years is usually worth repairing. Past ten to twelve years, replacement often makes more sense — here are the signs it is time to replace.
No hot water? Let’s get it fixed today.
Fast Water Heater Co. has been diagnosing and repairing water heaters across the West Coast since 1986. Book before noon and most repairs are handled the same day — licensed, permitted, and inspected.
Schedule Same-Day Repair
