Surviving a water shortage – how rainwater harvesting is the way of the future

As Auckland experiences a one in 100-year drought and the Hunua Dam is sitting at record lows, Auckland Mayor, Phil Gough says a $1 billion investment to treat household wastewater so it can be reused as drinking water is on the cards.

But until that costly project gets underway, harvesting rainwater at home is something homeowners can do now to ensure they are not relying solely on an uncertain municipal supply. Wherever you are in the country, if you have a rainwater harvester that is sitting idle or want some help getting up and running – PASLR can show you how.

How can rainwater be utilised?

Rainwater can be harvested and used for a range of different applications; for watering the garden or washing the car, for use in the laundry and toilet, or it can even be used as the sole water source for the family home including drinking water. Depending on how you want to use the rainwater there are several options available.

What do you need to harvest rainwater?

Most rainwater is harvested directly off the roof of your home and travels through down pipes to a water tank which sits either above ground or below. While not essential, gutter guards definitely help reduce organic matter which find their way into the tank and regular tank sterilisation is recommended. Due to the ongoing concerns with municipal water supply, many new builds are now required to have some sort of rainwater harvesting specified.

You’ll need a pump (submersible or surface) to transfer the water from the tank to where it needs to go. The size of the pump will depend on what you are using the water for i.e. whole house or just the garden.

We also recommend a controller such as the Davey Rainbank which automatically selects the water source you draw from, with rainwater given priority over mains supply. Mains water will be supplied when the tank is empty or in the event of a power outage.

Although collected rainwater is generally very good in regards to mineral and chemical components, it is in MOST CASES contaminated with microorganisms from faecal matter of birds, possums, cats, mice and rats.

If you want to use your rainwater for everything including drinking then the Ministry of Health recommends a two-barrier approach to this – namely, filtration followed by disinfection. Although we can provide a number of solutions that suit your requirements, the simplest solution is for cartridge filtration followed by ultraviolet disinfection. You can find out more about the three stages of filtration here.

Take a look at how the Davey Rainbank EVO works and how easy it is to install.