Water Harvesting

Why harvest rainwater?

Even a modest tank can improve resilience and help save treated water for when it’s truly needed.

By collecting and storing the rain that falls on your roof, you are:

Preparing for dry periods – having stored water can help delay or reduce the needs for water restrictions during droughts.
Reducing demand on our aquifers - by using harvested rain water to look after your vege garden and wash your car.
Taking pressure off stormwater networks - with water from downpipes being channeled into a tank.
Being more resilient – have water available if the council drinking water supply is disrupted during emergencies.

Rainwater harvesting systems can be as simple or as sophisticated as your needs and budget dictate.

How much rainwater do I need?

If you are looking at watering your average household garden and washing the car, a 250-400 litre tank will usually be more than adequate for your needs.

Gardens use about 20% of a household’s water.

National emergency guidance recommends storing at least 3 litres of drinking water per person per day for 7 days, plus extra for cooking, washing, and pets.

Even a small tank can make a big difference in an emergency.

Always boil rainwater for drinking and cooking.

How much rainwater can I harvest?

Based on average rainfall in:

Hanmer Springs - up to 170,000 litres per year could fall on a typical roof.
Amberley - up to 123,000 litres per year could fall on a typical roof.

How much you collect depends on the roof size, how many downpipes are connected and the size of your tank.

What tank size do I need?

This depends on space within your section, your budget, and what you want to use the water for:

200 – 400 L tanks: common and suitable for many town properties.
500 – 1,000 L slim or narrow tanks: useful where space is limited.
Larger tanks (5,000 L and above): typically for larger sections.

For most urban households, small to medium tanks are the most practical starting point. You can even start with wine barrels.

Under the district plan, tanks up to 2.5 metres in height with a 10 square metre footprint are permitted without a resource consent. Above that size, setbacks from houses and property boundaries, and other District Plan rules apply

No building consent is required for tanks up to 35,000L supported on the ground, and tanks up to 500L supported by a structure not more than four metres above the ground. For more details visit: https://www.canibuildit.govt.nz/tanks or come chat to our Building Team.

Maintenance considerations

Good maintenance keeps water cleaner and the system working well:

Keep roofs and gutters clear of leaves.
Use a leaf filter and first-flush diverter.
Check and clean fittings as recommended by the supplier.
Manage overflow through existing downpipes.

What will it cost me?

Approximate costs for a basic setup:

250 L tank: from ~ $245.
1,000 L tank: ~$600 – $1,000+.
Extras (leaf eater, diverter, fittings): ~ $150–$250.

A simple garden-use system can start from around $500 or less, depending on your setup.

Tank suppliers (in no order of preference)

The list of suppliers below is just a starting point and does not imply that Council endorses or approves them. Please take the time to do your own research.

Rain Tanks NZ: https://raintanks.kiwi/

Mico: https://www.mico.co.nz/

Bunnings: https://www.bunnings.co.nz/

Hynds: https://www.hynds.co.nz/

Thin Tanks NZ: https://thintanks.co.nz/

Mitre 10: https://www.mitre10.co.nz/

Humes: https://www.humes.co.nz/

PGG Wrightson: https://www.pggwrightson.co.nz/

Farmlands: https://www.farmlands.co.nz/

Farm Source: https://store.nzfarmsource.co.nz/

The Tank Guy: https://thetankguy.co.nz/product-category/garden-t...

Mr. Tank Water Solutions: https://www.mrtank.co.nz