No Hot Water? Here’s What Usually Causes It

You turn on the shower, wait, and it never warms up. That’s a rough way to start the day, especially on a cold Sonoma County morning. The good news: most no-hot-water calls come down to a short list of causes, and plenty of them are a repair, not a whole new water heater.

Below are the safe things you can check yourself, what each symptom usually means, and when it’s time to call. If you’d rather skip all that, call or text Ray’s Rescue Plumbing and we’ll sort it out.

Same-day service available. Our regular hours are Monday through Friday, 7am to 5pm, and we take emergency calls. If it’s after hours, call anyway. We’ll tell you honestly when we can be there. No-cost water heater estimates.

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First: Is It the Whole House or Just One Faucet?

This one question saves a lot of guessing.

• No hot water anywhere in the house: the problem is almost always at the water heater, or the gas or power feeding it.
• Hot water works everywhere except one faucet or shower: the water heater is probably fine. A worn cartridge or a stuck shower valve is the more likely cause. That’s a fixture repair or replacement, not a water heater job.
• Hot water that starts out fine and runs out fast: usually sediment in the tank, a failing element on an electric heater, or a heater that’s too small for the household.

Quick, Safe Things to Check Before You Call

These take a few minutes and sometimes solve it on the spot:

• Electric water heater: look at your electrical panel. If the water heater breaker has tripped, reset it once. If it trips again, leave it off and call us. Something is shorting, and resetting it over and over isn’t safe.
• Gas water heater: look through the small window near the bottom of the tank. Newer units may show a status light instead. If the pilot is out, follow the lighting instructions printed on the label on the tank. If it won’t light, or goes out again, stop there.
• Thermostat or gas control setting: make sure the dial wasn’t bumped to “Vacation,” “Pilot,” or the lowest setting. This happens more often than you’d think, especially in a busy garage.
• Tankless water heater: check the display for an error code and write it down. Make sure the unit has power and the gas valve to it is open.

Please don’t DIY the gas side. Don’t take apart gas controls, burners, thermocouples or venting. If you smell gas, don’t try to light anything. Leave the house and call PG&E or 911 from outside. And don’t remove the access covers on an electric water heater; there are live wires behind them.

Common Causes of No Hot Water

No power or no gas getting to the heater

A tripped breaker, a gas valve that got turned off, or a gas service interruption will stop a perfectly good water heater cold. If you just had gas work done, or PG&E was out, start here.

Pilot or thermocouple problems (gas tanks)

If the pilot keeps going out, a worn thermocouple or a dirty pilot is the usual cause. On newer units it may be the igniter or flame sensor. These are common repairs and normally don’t mean the tank is done.

Failed heating element or thermostat (electric tanks)

Electric water heaters have one or two heating elements and thermostats. When one fails, you get lukewarm water or none at all. Replacing the bad part is usually a straightforward repair.

Sediment buildup

Minerals in the water settle at the bottom of the tank. Over time that layer gets between the burner or element and the water, so the heater works harder and heats less. Popping or rumbling sounds from the tank are a classic sign.

A leaking tank

If there’s water on the floor and you also lost hot water, look closely at where it’s coming from. A fitting or the relief valve can usually be fixed. If the tank itself is leaking, it can’t be repaired and needs to be replaced. Turn off the cold water supply to the heater if you can safely reach the valve, and call us.

Tankless error codes and scale

Tankless units shut down to protect themselves and show an error code. Common culprits are mineral scale in the heat exchanger, an ignition or gas supply problem, a clogged inlet filter, or a venting issue. Many are fixed with a repair or a descaling. When you call, give us the brand and the error code so we can come prepared. More on our tankless water heater page.

Repair or Replace? Plain Answers

We’ll find the cause first, then tell you straight which way makes sense, with a price before any work starts.

• Repair usually makes sense when the heater is fairly young and one part has failed, like a thermocouple, element, thermostat, gas control or valve.
• Replacement usually makes sense when the tank is leaking, the heater is near the end of its life (a standard tank often lasts around 8 to 12 years), or an older unit needs a costly repair.
• Thinking about tankless? If you’re replacing anyway, it can be a good time to look at it. We’ll tell you honestly whether tankless or a new tank is the better fit for your home.

Replacements include hauling away the old heater, proper connections and venting, the earthquake strapping California requires, an expansion tank where needed, and testing before we leave. Details are on our water heater repair & replacement page.

Why Sonoma County Water Heaters Lose Heat

A lot of homes around here have hard water, especially homes on a private well. Those minerals end up as sediment in the bottom of a tank and as scale inside a tankless heat exchanger. That’s why flushing a tank and descaling a tankless unit on a regular schedule matters here. It’s one of the easiest ways to avoid a no-hot-water morning.

We’re based in Cotati and work for homeowners. Serving Sonoma County. That keeps us close to Cotati, Rohnert Park, Santa Rosa, Petaluma and the towns around them. Not sure if we come to you? See our service areas.

What Happens When You Call

• Call or text (707) 596-3095. Tell us gas, electric or tankless, and roughly how old it is. A photo of the label on the heater helps.
• We find the cause and explain your options and the price before any work starts.
• We fix it or replace it, clean up, and make sure you have hot water before we leave.

No Hot Water FAQ

Why do I have no hot water all of a sudden?

The most common causes are a tripped breaker on an electric heater, a pilot that went out on a gas heater, a failed part like a thermocouple or heating element, or a tankless unit that shut down with an error code. Check the breaker, the pilot and the thermostat setting first. If that doesn’t fix it, call or text (707) 596-3095.

No hot water but cold works — what does that mean?

It means your water supply is fine and the problem is on the hot side. If no faucet in the house has hot water, it’s almost always the water heater or the gas or power to it. If only one faucet or shower has no hot water, it’s more likely that fixture’s cartridge or valve.

Should I repair or replace my water heater?

If the heater is fairly young and one part has failed, repair usually makes sense. If the tank is leaking or the heater is near the end of its life, replacing it is usually the better buy. We’ll tell you which makes sense and give you a price before any work begins.

Do you offer same-day water heater service in Sonoma County?

Yes, same-day service is available, depending on the schedule and parts. Our regular hours are Monday through Friday, 7am to 5pm, and we take emergency calls. Call or text (707) 596-3095 and we’ll tell you when we can be there.

Are water heater estimates free?

Yes. Water heater and tankless estimates are no cost. Call or text (707) 596-3095 to set one up.

More answers on our FAQ page.

Other Ways We Help Around the House

• Tankless Water Heaters
• Water Heater Repair & Replacement
• Drain & Water Line Repair
• Fixture Replacement
• Leak Repair

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What Neighbors Say

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