No hot water — is it an emergency and what should you do?
Updated 3 July 2026
Losing hot water is disruptive but often fixable. What to check depends on whether your heating still works — that narrows down the cause quickly.
Heating works but no hot water
This usually points to a diverter valve (in a combi boiler) or a cylinder thermostat / immersion heater issue in a stored-hot-water system. Check the hot water is switched on at the programmer and the temperature is set high enough.
If you have an immersion heater, check its switch and thermostat — a tripped immersion is a common and cheap fix.
No hot water and no heating
That points to the boiler itself. Check the pressure gauge, any error code, the power supply, and your gas supply. See our boiler breakdown guide for the full checklist.
Getting it sorted
If the basic checks don't restore hot water, a plumber can diagnose it quickly. FixDelivered finds and confirms a qualified local plumber for you — you'll see their callout fee upfront.
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Get help now →Frequently asked questions
Is no hot water an emergency?
It's not usually dangerous, but it's a priority — especially with children or vulnerable people. If it's paired with no heating in cold weather, treat it as urgent.
Why do I have heating but no hot water?
Most often a faulty diverter valve in a combi boiler, or a cylinder thermostat / immersion issue in a stored system.
How much to fix no hot water?
Diagnosis and minor repairs are typically £60–£150 plus parts; a diverter valve replacement can be more. The plumber confirms the cost before starting.