Hot water temperature NZ

Did you know that there is legislation in New Zealand that determines and regulates how hot water should be in your home?

Your hot water guidelines are governed by the Building Code

The temperature of water in homes and other buildings is part of the New Zealand Building Code, sitting under the plumbing and drainage guidelines for acceptable building standards.

“The Building Code sets clear expectations of the standards buildings should meet. It covers aspects such as structural stability, durability, protection from fire, access, moisture control, services and facilities, and energy efficiency. The Building Code states how a building must perform in its intended use rather than describing how the building must be designed and constructed.”

The Building Code sits under the Building Act, and is enforced by the Ministry of Business, Innovation and Employment  (MBIE).

It is, therefore, a mandatory requirement by NZ government legislation to have the water in your home at the correct temperature.

What is the ideal temperature of your hot water?

Hot water in residential housing should be no hotter than 55oC when it comes out of the tap. This is probably the main piece of information that applies to most households.

There are also other details from the NZ Building Code to be aware of:

  • Hot water should be stored at 60°C or higher to eliminate the risk of Legionella bacteria growth.
  • Hot water delivered to sanitary fixtures (hand basins, baths, bidets and showers) should not exceed 45°C for early childhood education centres, schools, nursing homes, institutions and hospitals or similar facilities for young, sick, elderly and disabled people.
  • Hot water delivered to sanitary fixtures (hand basins, baths, bidets and showers) should not exceed 45°C for other buildings.

What happens if your hot water is too hot?

Water that is too hot poses a hazard to anyone, but in particular, it can be quite dangerous for children and elderly people.

  • Children often receive serious scalds because they have more sensitive skin than adults and burn more quickly.
  • Elderly people often have thinner skin that can burn more easily. They can also be vulnerable due to disabilities or slow reaction times.

Wondering how quickly hot water can burn skin? Have a look at the following times it takes to cause third-degree burns by hot water:

68oC water = 1 second to burn human skin

60oC water = 5 seconds to burn human skin

53oC water = 1 minute to burn human skin

Water that is too hot may not be good for your skin. It may lead to dry or irritated skin, and it may make eczema worse. Some health professionals also discourage extremely hot baths or showers for people who are at risk of high blood pressure or cardiovascular disease.

Lastly, setting your water temperature too high will also create higher power or electricity bill. Heating water costs money – whether that’s long, hot showers or hot laundry cycles (you actually don’t need to wash and rinse with hot or warm water).

What happens if your hot water is not hot enough?

Water that is not hot enough creates the risk of harmful Legionella bacteria growing in storage water heaters. Legionella bacteria can cause Legionnaire’s disease – a severe form of pneumonia. This can be very dangerous for people over the age of 50 and people with weak immune systems, chronic lung disease or heavy tobacco users.

The solution to this problem is to store hot water at a minimum temperature of 60oC and deliver it to baths, showers, basins and bidets at a temperature no greater than 55oC.

How do you control the temperature of your water?

Tempering valve

Installing a tempering valve is one way of controlling the temperature of your water. A tempering valve is attached to the hot water pipe from the hot water cylinder. This creates enough cold water mixed with the hot water to keep it at the desired temperature you set.

Hot water cylinder thermostat

You can set the thermostat on your hot water cylinder to a specific temperature. Remember, water in your hot water cylinder should be stored at a minimum temperature of 60oC.

Temperature control faucets

There are different valve-like devices, such as mixer taps, single handle mixers, temperature control valves, and thermostatic mixing valves, which are used to regulate the temperature of the water before it comes out of the tap.

Instantaneous or continuous flow water heaters

Instantaneous or continuous flow water heaters, through the use of water controllers, allow you to control the temperature of hot water to a safe level.

If you would like us to check your water temperature levels, or need us to show you how to check and adjust your hot water temperature, please get in touch with our gas hot water experts and we’ll be happy to help.