Choosing a rainwater tank

Tanks are available in a range of materials in different shapes and sizes. The most common material used is galvanised steel which is light and provides for easy transportation. Concrete and ferro-cement tanks are strong and long lasting and can be installed under the ground. Fibreglass tanks suitable for collecting rainwater are manufactured with a food-grade coating on their interior surface. There is also an increasing range of tanks manufactured from synthetic polymers including polyethylene. Plastic tanks should be constructed of materials that are at least food-grade standard.

Customers considering the purchase of a rainwater tank should be aware that Australian Standards and guidelines apply to the design, material, manufacture and installation of rainwater tanks.

To be eligible for a rebate under the Living Victoria Water Rebate Program, rainwater tanks must be designed and manufactured to the relevant Australian Standards. Rainwater tanks must also be certified to the relevant Australian Standards before 1 July 2012 to be eligible for a rebate after this date.

The size of tank you need depends on a number of factors including the roof area, water usage and physical constraints of your property. Obviously the larger the tank, the more effective it is in conserving water.

Installation and maintenance

Your roof size will determine the volume of water you are able to harvest. You may need to make changes to the position of your downpipes or gutters to maximise the volume of water flowing to your tank.

Overflows or discharge pipes from roof mounted evaporative air conditioners or hot water systems should not be allowed to discharge onto the roof catchment area.

Safety and water quality

Making sure water quality is good depends on correct design and installation, followed by sensible maintenance of your rainwater tank and catchment area.

When installed, your tank should be covered and every access point, except the inlet and overflow, should be sealed. If an access point is left uncovered, there's a risk of children, adults and animals drowning or contaminating the water. The inlet should incorporate a mesh cover and a strainer to keep out foreign matter and to stop mosquitoes and other insects getting into the tank. The overflow should be covered with an insect-proof screen.

You should not use a rainwater tank to supplement or provide your main source of drinking water if you live in an area affected by heavy traffic, industry, incinerators and/or smelters. For more information download the Your Private Drinking Water Supply booklet, which provides simple information to help keep your domestic drinking water supply safe and healthy.

Permits and regulations

Before you purchase or install a rainwater tank check out the health, building or council regulations in your local area. To qualify for a Living Victoria Water Rebate, your rainwater tank must be installed by a licensed plumber who will provide a copy of the Plumbing Industry Commission (PIC) certificate where the cost of the tank and associated plumbing is in excess of $750.

Reference: ‘Guidance on Use of Rainwater Tanks’ 2nd edition by enHealth Council