Why is there no hot water from my bathroom tap?
If a bathroom tap runs cold but never becomes hot, the cause could be limited to that tap or affect the whole hot-water system. Comparing other outlets first can quickly show whether you need a plumber or a heating engineer.
Check whether the problem affects one tap or the whole home
Try the hot tap at the kitchen sink and any other bathroom outlets. If they all stay cold, check whether your boiler is showing a fault code or whether a hot-water cylinder is switched on and scheduled to heat. Follow the appliance manufacturer's instructions and do not remove covers.
If other taps become hot normally, the problem is probably local to the affected bathroom tap, its valve or the pipe supplying it.
Why would only one bathroom tap have no hot water?
A service valve beneath the basin may be closed or partly closed, especially after recent work. A tap cartridge can also seize or become blocked by debris. On a mixer tap, an internal fault may stop hot water entering even though the handle still moves normally.
Do not force a stiff handle or dismantle a tap unless you can safely isolate the water. A plumber can check the local valve, flow and cartridge without disturbing more of the bathroom than necessary.
What if every hot tap is cold?
With a combi boiler, loss of hot water can be caused by low system pressure, a boiler fault or the boiler not detecting demand. With a cylinder, the programmer, immersion heater, boiler or controls may be involved. A power cut or changed timer setting can also interrupt heating.
Use only the normal controls and consult the appliance manual. Gas boilers should be repaired by a Gas Safe registered engineer; fixed electrical heating faults require a suitably qualified professional.
What if the water is only lukewarm?
Lukewarm water can point to a mixer cartridge fault, a temperature control setting or insufficient stored hot water. If it begins hot and quickly cools, note how long it lasts and whether another outlet was running at the time. That information helps identify a tap issue, limited cylinder capacity or a heating-system problem.
When is it urgent?
Turn off the relevant water supply and seek help promptly if the tap or pipe is leaking. If you smell gas, suspect carbon monoxide or a boiler alarm activates, leave the property and follow the emergency advice from the National Gas Emergency Service. Do not attempt a boiler repair yourself.
Quick no-hot-water checklist
- Compare the affected tap with other hot taps.
- Check the boiler display or hot-water timer normally.
- Look for a recently closed local service valve.
- Note whether the flow is cold, lukewarm or completely absent.
- Do not force handles or remove appliance covers.
- Tell the professional whether recent plumbing work was carried out.