Setting up a rainwater tank

Installing a rainwater tank to collect water for outdoor use is easy to do, and in most situations, you won't need a building consent.

Rewi Elliot puts stored rainwater to good use at Otari-Wilton's Bush.

So you want to install a rainwater tank?

Diverting rainwater from your downpipe to a storage tank is a great way to reduce your use of treated water especially for gardening or outdoor cleaning.

It can also increase your options in the event of as water supply emergency.

It can be relatively simple to install a kit that diverts the 'first flush' of rain from your roof and gutters, which contains most of the contaminants, away from your tank, feeds clean water into your tank, then directs overflow back into your stormwater system.

Do I need council consent?

For Outdoor Use - urban areas.

If you're installing a typical (say, 2,000 litre) tank to collect rainwater for outdoor use only, such as garden watering or emergency supply, then as a general rule you don't need a building consent in Hutt City, Upper Hutt, Wellington or Porirua.

Please note however that other considerations may apply, such as the resource consent requirements for your area.

For example, if you were planning to put your tank on an elevated platform you would still need to observe the height and boundary limits that apply in your area, and there are capacity limits relating to height above ground as well. Call your local council if this applies to your situation

For indoor use

If you're planning to connect your rainwater tank to your toilet or washing machine, you will need a building consent.

This is to ensure pipe entry to the house is properly sealed, and that rainwater from your system can't enter the public water network. You will need a registered plumber to carry out this work for you.

And if you want to use if for drinking, you'll need to have the water treated or purified, and may need an annual inspection. Again, contact your local council's building consents team for details.

What else do I need to know?

You will need to regularly check and clean your gutters and should at least have a filter over the inlet to the tank. And remember rainwater collected from your roof is not suitable for drinking without treatment - you might consider affixing a sign near the outlet tap.

Why do it?

We drink or cook with only about 5% of the treated water that is piped to our homes. The rest ends up in the waste-water system, used for washing, cleaning, gardening or simply wasted.

Using a rainwater tank for garden or lawn watering can reduce your water use by around 20% - depending on your needs, of course.

Up to 65% of water use can be replaced by plumbing a rainwater collection system into your toilet and washing machine.

Council contact numbers

Wellington 499 4444

Hutt City 570 6666 (Ask to speak to the Eco Design Advisor, or e-mail ecodesign@huttcity.govt.nz)

Upper Hutt 527 2169

Porirua 237 5089

Your water