No Hot Water? Quick UK Checks & When to Call a Plumber
By The FixDelivered Team · Updated 2026-09-08 · 5 min read
Losing your hot water can be a real inconvenience, especially on a cold morning. While it often feels like a major problem, many 'no hot water' issues can be resolved with a few simple checks. This guide will walk you through troubleshooting steps you can safely perform yourself and, crucially, advise you on when it's time to call in a qualified professional, particularly if gas is involved.
Initial Checks When You Have No Hot Water
Before you panic, take a moment to assess the situation. A systematic approach can help you quickly identify the problem.
Is it All Hot Water or Just One Tap?
First, check all your hot water taps. Is the issue widespread or confined to a single tap or shower? If it's just one, the problem is likely with that specific fixture, its local mixer, or a blockage, rather than your main hot water system.
Check Your Power Supply
Many hot water systems, including combi boilers, immersion heaters, and electric showers, rely on electricity.
- Fuses and RCDs: Head to your consumer unit (fuse box). Look for any tripped RCDs (Residual Current Devices) or blown fuses associated with your hot water system or boiler. Flick the RCD switch back up. If it trips again immediately, there's an electrical fault that needs professional attention.
- Immersion Heaters: If you have an immersion heater, check its dedicated switch on the wall or at the consumer unit.
Safety Note: Never attempt to repair electrical faults yourself. If an RCD keeps tripping, call a qualified electrician.
Boiler Pressure (for Combi and System Boilers)
For homes with a combi or system boiler, low water pressure is a common culprit for a lack of hot water.
- Check the Gauge: Locate the pressure gauge on your boiler. It should typically read between 1 and 1.5 bar when cold.
- Topping Up Pressure: If the pressure is below 1 bar, you might need to top it up. Most modern boilers have a filling loop (a silver braided hose with two valves, often black or blue). Consult your boiler's manual for specific instructions on how to repressurise it. Turn both valves slowly until the gauge reaches 1 to 1.5 bar, then close both valves tightly.
When to Call a Professional: If you're unsure how to repressurise your boiler, or if the pressure drops repeatedly after topping it up, it indicates a leak or another fault requiring a Gas Safe registered plumber.
Review Your Boiler or Immersion Heater Settings
It might sound simple, but sometimes settings get changed accidentally.
- Programmer/Timer: Ensure your hot water is scheduled to be on. Check the timer settings on your boiler or hot water cylinder.
- Thermostat: For immersion heaters or hot water cylinders, check the thermostat setting. Make sure it hasn't been turned down too low.
- Boiler Display: If you have a modern boiler, check its digital display for any error codes. A quick search online with your boiler model and the error code can often point you to the problem.
When to Call a Professional Plumber
While some issues are easily fixed, others require the expertise of a qualified professional. Knowing when to step back is crucial for safety and to prevent further damage.
Gas Boiler Issues
This is paramount: If you suspect a problem with your gas boiler, especially if you smell gas, hear unusual noises, or see a pilot light that won't stay lit (on older models), you MUST call a Gas Safe registered plumber immediately. Never attempt to repair a gas appliance yourself. Working on gas appliances without being Gas Safe registered is illegal and extremely dangerous, risking carbon monoxide poisoning, explosions, or fires. Turn off your gas supply at the meter if you smell gas and ventilate the property.
Persistent Problems or No Easy Fix
If you've run through the above checks and still have no hot water, or if the problem recurs, it's time to call in a professional. This includes:
- Repeatedly low boiler pressure.
- No power to your immersion heater despite checking fuses.
- Boiler error codes you can't resolve.
- Any signs of water leaks from your boiler or hot water cylinder.
- If you have no hot water and no cold water, suggesting a mains supply issue.
What to Expect from a Plumber and Costs (2026 Guide)
When you call a plumber, they will diagnose the issue and provide a quote for the repair.
- Call-out Fees: Typically, a plumber's call-out fee in the UK in 2026 might range from £80-£120 during standard hours. For emergency services outside of these hours, expect to pay between £150-£250+.
- Repair Costs: The total cost will depend on the complexity of the repair and parts needed. A simple reset or minor adjustment might cost £150-£300 including the call-out. More involved repairs, such as replacing a diverter valve in a combi boiler, could range from £300-£600+.
- Boiler Replacement: In the worst-case scenario, if your boiler is beyond economical repair, a full replacement can cost anywhere from £2,000-£4,000+, depending on the boiler type and complexity of installation.
Always ask for a clear breakdown of costs before any work begins. For urgent issues, you can always tell us your emergency at FixDelivered and we can connect you with qualified local plumbers.
Getting Professional Help Fast
When you need a reliable plumber quickly, FixDelivered can help. We connect you with qualified local plumbers who can diagnose and fix your hot water issues. Our service allows you to find emergency plumbers near you, often with upfront agreed call-out fees. You can learn more about how FixDelivered works, or simply get a plumber now.
Having no hot water is inconvenient, but by following these checks, you can often identify the problem or at least provide valuable information to a professional. Remember, safety first, especially when dealing with gas or electricity. Don't hesitate to call a Gas Safe registered engineer for any boiler issues or a qualified plumber for other persistent problems. Early intervention can often prevent more costly repairs down the line.
Frequently asked questions
Why is my hot water not working but heating is?
This often points to an issue with your diverter valve (in combi boilers), immersion heater, or hot water cylinder thermostat. It means the boiler or system is providing heat for radiators but not directing it to the hot water tap. A Gas Safe engineer can diagnose this.
How do I reset my boiler?
Most modern boilers have a reset button, often marked with an 'R' or a flame symbol with a line through it. Press and hold it for a few seconds. Consult your boiler's manual for specific instructions, as incorrect resetting can sometimes worsen issues.
How much does it cost to fix no hot water in the UK (2026)?
Costs vary significantly. A plumber's call-out fee typically ranges from £80-£120 (day) or £150-£250+ (emergency). Simple fixes might cost £150-£300 in total, while more complex repairs could be £300-£600+. Always get a detailed quote.
Can I fix no hot water myself?
You can perform initial checks like ensuring the power supply is on, checking boiler pressure (and repressurising if needed), and reviewing timer settings. However, for any gas-related issues, persistent electrical faults, or complex boiler repairs, you must call a Gas Safe registered professional.
Need a plumber now? Tell us your emergency and FixDelivered will find and confirm an available local plumber near you, usually within the hour.
Written by the FixDelivered Team. Reviewed by Rupert Lowe, Editor. Last updated 2026-09-08.