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Hot water cylinders

Take the time to fix and fasten your water tanks and pipes. These could be a valuable source of water following a natural disaster.

Earthquakes can cause hot water cylinders and header water tanks to rock or move, cracking pipes and causing expensive and messy water damage. In large earthquakes, cylinders may slide making hot water a hazard.

Icon showing a hot water cylinder

Securing hot water cylinders

Securing a hot water cylinder is surprisingly easy, and something you can do yourself.

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You can buy hot water cylinder restraint kits from hardware stores. These have the strap, screws and turnbuckle you need. Follow the manufacturers’ installation instructions or follow these steps:

  1. Screw or nail timber blocks to the floor or any shelving it sits in or alongside (make sure the shelf is fastened). 
  2. Cut timber blocks to size so they fit snugly between the top of the cylinder and walls, then glue them into place. Ensure the blocks are fastened against the wall framing. 
  3. Screw two 8 mm screw hooks into the studs on either side at the same level as the blocks.
  4. Attach a turnbuckle to one hook and the end of the strap. Cut the strap to the length you need, connect it to the other hook and use the turnbuckle to make it tight.
Icon showing a header tank

Securing header tanks

It’s important to check your roof space and secure heavy items you might not realise are there, such as a header water tank.

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Older houses may have a header tank. This is a water tank in the attic, roof space, or on the roof, that feeds the hot water cylinder and helps manage the water pressure. The tank will be heavy especially if it's full, and could damage your home if it moves or spills in an earthquake. Make sure you fasten it so it doesn’t wobble, shift or even crash through the ceiling. Try doing the following:

  • strap the header tank to the ceiling framing
  • nail timber blocks to the platform at the base of the tank tray to stop it sliding
  • fit wooden blocks between the perimeter of the tray and the tank.

An empty and unused header tank is unlikely to cause any damage, but it’s a good idea to take it out of your ceiling if possible. 

The Wellington City Council website has more information on water storage and heat appliances Your own council might have information on their website.

Icon showing a bottle of water

Using your stored water

If your water supply is cut off by a natural disaster, or for some other reason, you can get water from your hot water cylinder or header tank.

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If you need water, for example if your supply is cut off following a natural disaster, you can use the water stored in your hot water cylinder.

Make sure you know how to shut off the water supply to the tank, including from the toby on the street, to stop dirty water flowing back into your pipes. The pipeline between the toby and your house could break – so consider how you might clamp the pipe or improvise at the time. 

You’ll need to:

  • turn off the electricity before you start to drain the tank
  • know how to open the air inlet valve and the drain valve so that you can relieve the pressure and let the water flow. 

Replacing old plumbing

Plumbing, stormwater and sewerage pipes may break during an earthquake, especially older style clay pipes.

If you’re getting plumbing work done, talk to your plumber about replacing any old pipes and connections with flexible gas and plumbing fittings. These allow for extra movement and may prevent breaks and leaks in an earthquake.

Are your tanks secured?

  • Do you have a header tank in your attic or roof space? Whether full or empty, make sure it’s secured.
  • Is your hot water cylinder secured? If not, buy a kit from the hardware store and secure your tank today.
  • Make a note to find out about replacing old pipes when you next get plumbing work done.