FAQ

Frequently Asked Questions – Rainwater Tanks

1. Why should I harvest rainwater?
2. Why choose stainless tanks for water storage?
3. Can I use rainwater for my household water usages?
4. How much rain can I harvest from my roof?
5. What happens if I run out of tank water which is fed into the house?
6. Do I need a pump for my tank?
7. What size of stainless tank suits my requirement?
8. Can I paint over stainless steel water tanks?
9. Do I need a building consent/permit for water tanks?

1. Why should I harvest rainwater?

Rainwater harvesting can save you money on water bills by reducing your mains water consumption and provide you with a back-up water supply in case of emergency such as earthquakes or droughts. Rainwater is better for your vegetable garden as it has a balanced pH and is free of chemicals such as chlorine. These advantages not only benefit you or your family but the community as a whole as we can all maximise our use of rainwater to promote sustainability and reduce the pressure on mains water supply. Hence, there are environmental and financial benefits to have a water storage system in place.

2. Why choose stainless tanks for water storage?

There are a number of rainwater tanks on the market with many different sizes, styles, colours, shapes and materials. But, stainless steel is simply superior and here are some of the reasons why:

• They are hygienic and durable
• They never rust and look fantastic
• Stainless steel tank will not degrade in sunlight
• They are hygienic and durable
• They never rust and look fantastic
• Stainless steel tank will not degrade in sunlight
• Outlets can be positioned as per client’s requirement
• They are engineered for optimum weight to volume performance
• They are very portable; for instance, two men can carry a 5000L stainless tank and position it at a place where machine cannot access. Hence, transportation cost is minimised.
• Our unique manufacturing process means no rivets or other weak points
• They are fully welded for strength and durability
• They can withstand chill or heat
• They will not leak, twist, burst, warp, buckle, melt, or crack under normal usage and they won’t go up in smoke
• They are 100% recyclable and environmentally friendly
• Competitive overall ownership cost

3. Can I use rainwater for my household water usages?

Yes you can – but you’ll need to have a very good quality water filter in place if you are going to use the water for drinking, teeth cleaning, hand washing, bathing, showering, food preparation and cooking so that you are free from harmful germs and chemicals.

People who live in rural areas are generally not connected to a town water supply and most of them would collect rainwater from their roofs as their main source of tap water. Thus, it is important to ensure that the water going into the rainwater tank is as clean as possible.

If you would like to download information on Water Collection Tanks and Safe Household Water provided by the Ministry of Health, please click here.

4. How much rain can I harvest from my roof?

Every 1mm of rainfall over 1m2 = 1 litre of water. Therefore, if your roof is 20m long x 10m wide you will be able to harvest approximately 200m2 = 200 litres of water and 10mm of rainfall x 200m2 of roof will provide you with approximately 2000 litres of rainwater. You will need to work out how many m2 of roof you have draining into your down pipe that service your rainwater tank. Check your area’s monthly or annual rainfall average and multiply this by your available roof area to estimate your potential monthly or yearly water catchment.

5. What happens if I run out of tank water which is fed into the house?

If your tank water is to be used inside the house, then it will be necessary for the tank to have a ‘top-up’ connection with the mains supply. This would ensure that there is always enough water in the tank to service your needs. You could get a plumber to help you install a mains water top-up facility and a backflow prevention device to prevent tank water flowing back into the mains water supply.

6. Do I need a pump for my tank?

If your tank is well elevated and you are using the water for your garden via a tap and hose connection, you won’t need a pump. You can just let gravity do all the work for you. On the other hand, if the tank is not elevated but at (or below) ground level, or if you plan to make more extensive use of your tank, a pump will be necessary to boost the water pressure.

7. What size of stainless tank suits my requirement?

The size of the tank that you require depends on what you want to use the water for. The best recommendation is to install the largest rainwater tank capacity possible within the restraints of your budget, locality and council by-laws.

If you are only using the tank as a source for outdoor applications, like watering the garden and car washing, you could use a tank capacity of between 1000 and 5000 litres.

If you plan to integrate the tank into the household plumbing system, then you need to consider the size of your catchment area (i.e. the area of your roof surface), the amount of rainfall in your area and the sort of applications for which all of that stored rainwater is intended. If you want to be able to collect and store large quantities of rainwater, it would be best to have two or three tanks positioned in different locations around the house.

8. Can I paint over stainless steel water tanks?

Yes you can – simply apply metal primers first then you can be as creative as you like.

9. Do I need a building consent/permit for water tanks?

A building consent is generally not required for tanks used only for garden irrigation. However, this would also depend on a few criteria such as height and boundary limits if you are planning to put your rainwater tank on an elevated platform. Please check with your local council first.

A building consent is required for any tank connected to household plumbing. All plumbing must be carried out by a registered plumber and must comply with the New Zealand Building Code. This is to ensure that the pipe entry to your house is properly sealed and that rainwater from your system cannot enter the mains water supply.