What temperature should your hot water cylinder be?

Keep stored water hot enough for hygiene, and washing water safe for skin.

The answer in 2 lines. For a conventional hot water cylinder, current HSE guidance uses a storage temperature of 60°C to help control legionella. That is not a suitable washing or bathing temperature. Mixing controls can reduce the temperature delivered to users while keeping stored water hot. First establish whether you have a cylinder, an instantaneous heater or a heat pump system: their controls differ. Never open electrical covers or defeat safety devices to change a setting. If you rent, ask your landlord before altering the cylinder controls.

Start with your system

Identify whether your hot water is stored in a cylinder or heated on demand. A boiler's radiator temperature control may be separate from its hot water setting.
Check the user instructions and any accessible cylinder thermostat. If you cannot identify the control confidently, ask a qualified professional to show you.
If the water is unexpectedly hot or cool, note which outlets are affected and whether the problem is constant. Tell your landlord or heating professional before making repeated adjustments.

Stop: danger

Electrical covers: do not remove an immersion heater cover or reach inside equipment to adjust a thermostat.
Scalding water: keep children and anyone who cannot react quickly away from the affected outlet until the delivery temperature has been checked.
A scald has happened: follow NHS burns and scalds advice. Cool the injury under cool running water for 20 minutes and use the page's urgent-care guidance to decide what help is needed.

Storage temperature and tap temperature are different

The cylinder stores hot water for later use. A mixing valve blends hot and cold water nearer the outlet, limiting what reaches a bath, basin or shower. Turning down the cylinder is therefore not always the right response to an excessively hot tap.

The HSE temperature-control guidance gives at least 60°C for storage and at least 50°C within one minute at outlets when checking an unmixed hot water system. These are hygiene control references, not recommended bathing temperatures. A correctly functioning mixing valve changes what you measure at the outlet.

Why not simply turn everything down?

Legionella can multiply in water systems and cause illness when contaminated droplets are inhaled. Storage, circulation and regular use all matter. Reducing the cylinder temperature to make the shower comfortable can undermine the intended control measures.

Conversely, turning the cylinder to its maximum is not a sensible substitute for fault-finding. If hot water runs out unusually quickly, the problem may involve the heating schedule, controls or equipment. Ask for the cause to be checked rather than assuming a hotter setting will solve it.

What not to do

Using the temperature printed on a dial as proof that the whole cylinder and every outlet are performing correctly.
Disabling a heat pump's hot water hygiene programme or changing installer settings without professional advice.
Leaving a child unattended around bath taps, even where a mixing valve is fitted.

What England's building guidance says

The 2024 edition of Approved Document G describes limiting the hot supply to a bath to a maximum of 48°C using suitable temperature control. Read its hot water safety section with your installer to establish how it applies to your work.

This does not mean every existing bathroom tap in England has a blanket 48°C limit, or that you should store the cylinder at that temperature. Building guidance concerns particular work and circumstances. Wales, Scotland and Northern Ireland have separate building requirements.

If you rent, or have a specialist system

The HSE landlord guidance explains the duty to assess and control legionella risks. Read its tenant information section and ask your landlord what settings and precautions apply to your home. Report unreliable hot water, unusual temperatures or outlets that are rarely used.

Heat pumps, communal supplies and instantaneous heaters need advice suited to their design. Ask the responsible professional to explain the normal operating temperature, any hygiene cycle and how scald protection is provided. Before a prolonged absence, ask how to manage the system and restart it safely; do not copy a shutdown routine intended for different equipment.

Good to know

A comfortable shower does not demonstrate that stored water is hot enough: the shower may already mix hot and cold water.
A thermostatic mixing valve needs appropriate installation and maintenance. Ask for it to be checked if the outlet temperature becomes erratic.
Keep the operating instructions accessible and record any professional changes so other household members know which controls to use.

Illustrative example: Priya in Bristol notices that the bath tap has become much hotter. She keeps her children away from it and contacts her landlord. A professional checks the cylinder and mixing control, then restores safe delivery without simply lowering the stored water temperature.

A made-up story, for illustration.

Bobby

Sources, verification, confidence

Verified on 4 November 2026, for England. Confidence: high for HSE temperature-control guidance and NHS scald first aid; high for the bath provision in Approved Document G incorporating 2024 amendments; medium for the correct settings of an individual system, which depend on its design. Temperature references are current guidance, not annual statistics.