Hot water safety

Each year, hot tap water causes serious scalds to many small children and elderly or disabled people around Australia. More than 90 per cent of these scalds occur in the bathroom, where the delivery temperature of water from showers or taps is too high and a person cannot react quickly enough to avoid scalding.

  • At 68°C, it can take as little as one second to cause a full thickness scald.
  • At 50°C degrees, it takes five minutes.

This may not seem a big difference in temperature, but it can mean the difference between scarring for life, agonising pain, hospitalisation and skin grafts, or a relatively minor injury. In some cases, severe scalding can even result in death.

This is why the plumbing laws require a maximum temperature of 50°C at the outlets of each shower head or tap. This is hot enough for a bath or shower, but not hot enough to cause severe scalding.

The exception to the 50°C temperature requirement are premises intended for children, the elderly or people with disabilities – such as early childhood centres, schools, nursing homes or similar facilities. These premises have a maximum hot water delivery temperature of 45°C.

Tempering

Hot water needs to be stored above 60°C in hot water systems to prevent bacteria growth (such as Legionella), but a tempering valve ensures that the water comes out of the tap at a lower temperature.

Hot water systems installed before 5 August 1998 are unlikely to be tempered, but there are various ways of reducing the temperature of the water outlets, depending on your type of hot water system.

For the best advice, talk to a licensed or registered plumber. They may recommend:

  • installing a tempering valve, which reduces the hot water temperature in the bathroom, but does not affect the temperature in the kitchen
  • installing a thermostatic mixing valve that can be set to deliver hot water at a precise, safe temperature.

If you are buying a continuous flow hot water system, you can simply set the desired temperature with electronic control pads so that endless hot water is delivered at a safe pre-set temperature.

Preventing scalds

The maximum water settings above are not bathing temperatures – you may need to mix cold water with hot water for baths and showers. The maximum bathing temperature recommended for young children is 37 to 38°C.

Ways to reduce the risk of burns in the bathroom include:

  • Always run cold water first.
  • Never leave your child alone in the bathroom.
  • Never leave a small child in the care of an older child, who may be able to turn on the hot water tap.
  • Keep the bathroom door closed when not in use.

First aid if someone is scalded by hot water

In the event of a scald, you should:

  • Remove clothing quickly. This helps the heat escape from the skin. But leave the clothes on if they are stuck to the skin.
  • Immediately hold the burn under cold water running water for 20 minutes only. This will stop further burning. It also helps to relieve the pain. Never use oil, butter or ointment, as these can further damage the skin.
  • Cover the scald with a loose, non-stick dressing (e.g. dressing from a first aid kit), cling film or a clean cloth and keep the person warm. See a doctor if the scald larger than 3 cm, has blisters or is on the hands, face of genital area.

For more information see The Royal Children’s Hospital fact sheet: Burns – prevention and first aid.