Take the pressure down: water heater explosion prompts maintenance reminder

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Some quick checks and routine maintenance could have prevented the explosion of a storage water heater outside a home in Perth’s north, according to Building and Energy inspectors who attended the site.

The incident is a timely reminder for owners of all storage water heaters – gas, electric and solar – to follow the recommended maintenance schedule, which usually involves simple checks every few months.

Last month’s explosion split open the metal casing of the gas water heater outside a Yanchep former show home, which had recently been sold and occupied.

Inspectors believe the water supply’s high mineral content and infrequent use caused calcium to build up inside the unit, blocking the valves and preventing the thermostat from sensing the water temperature.

“This created a perfect storm where the water heater continued to heat up without the temperature safety controls kicking in, while the heated and pressurised water inside had nowhere to go,” Building Commissioner and Director of Energy Safety Ken Bowron said.

“Fortunately, no one was injured and incidents such as this are rare. However, it is a reminder of the potential dangers and how to prevent them through simple checks, such as opening the valves for a few seconds every six months.

“We advise home owners to follow the maintenance instructions provided by the manufacturer, and contact a licensed plumbing contractor if they have any concerns.”

Tips for checking your storage water heater (also see diagram)

Check the owner’s manual for instructions on your particular system. Common maintenance recommendations include:

  • Every six months… gently open and close two levers on the unit’s exterior: the expansion control valve and the temperature pressure relief valve.
  • Every 12 months… check the unit’s built-in temperature controls are working by making sure the water coming from the nearest tap isn’t too hot.
  • At least every five years… contact a licensed plumbing contractor to replace valves that control expansion, temperature and pressure. This may need to be done more frequently in hard water areas.
  • Around every five to 10 years… arrange for a qualified person to replace the anode to help to reduce corrosion. Different anodes suit different water types.
  • If you go away for a week or more…  When you return, clear any hydrogen build-up by turning on a hot tap and checking the water runs freely (not spurting) before using any electrical appliances linked to the hot water system.


Note: Building and Energy (a division within the Department of Mines, Industry Regulation and Safety) was formed in January 2018 by the amalgamation of the Building Commission and EnergySafety. Building and Energy oversees the WA regulation of building, painting, building surveying and plumbing services, and is responsible for the technical safety regulation of all electrical and most gas industries.

Media contact:

Sarah Roberts – 0466 409 828 or bemedia@dmirs.wa.gov.au

exploded_water_heater_-_yanchep.jpg, by cmurphy
Photo: Calcium build-up played a role in the explosion, which split open the gas water heater’s metal casing
water-valve-facebook-graphic.png, by cmurphy
Graphic: When did you last check your water heater?


Building and Energy
Media release
08 Aug 2018

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