Rain Water Tanks
Rainwater Tanks, Installation and Options
Water Installations, trading as "Water Technology", offers our clients a range of services, including the
purchase, delivery and installation of rainwater tanks. We manufucature the smaller steel type, however a
complete range of tanks is available, including polyethylene tanks, fibreglass, aquaplate and steel-liner tanks.
What are the benefits of rainwater tanks?
Collecting rainwater has many environmental benefits, as well as benefiting you! Some reasons for
harvesting rainwater include:
- Making fresh water available to flush toilets or to provide a laundry source.
- Using rainwater for drinking purposes.
- Supplementing the watering of garden areas.
- Reducing our use of mains (scheme) water - a very valuable, limited resource.
- Saving some money – buying less water from a service provider.
- Providing a water source which has reduced levels of salts and other substances.
What Options are Available
You can install any size of rainwater tank. However, some larger sizes, and with connections to a
house supply, can attract a rebate from the state government. Most people want to use the rainwater
- either for drinking or to flush toilets or to wash clothes.
GRS mainly installs tanks which enable the household to use the water in the house -
usually for the kitchen, bathroom/toilet and/or laundry
Connections to the House
Rainwater is most often pumped to the house, although gravity can be used in some cases to
direct rainwater to fixtures in the house.
A pressure-tank pump is used to supply rainwater when required. When the tap is turned on,
or the toilet flushes, the pump is activated and gently pumps water to fill the cistern,
or enter the kitchen sink or washing machine
The tank on top of the pump permits water to be pumped under pressure. Instead of the pump turning on every
time the tap is opened, the pressure inside the cylinder may be enough to supply the water to the house fixture.
The pressure-tank pump system is only one of many ways to supply the household. GRS provides advice on a
number of different types of pumps, as each has particular applications.
What happens when I run out of rainwater?
If you only install a small tank (e.g. less than 20 000 L) then it is likely you will run out of
rainwater during the summer period. This, of course, depends on the uses of the rainwater.
Providing a full laundry, kitchen and bathroom service rapidly depletes the volume you can collect
during rainy times.
GRS integrates the mains (scheme) water source with the rainwater source. Generally, a double
check valve is connected to both, and when the rainwater is depleted, you simply turn a couple
of ball valves to enable mains water to enter the system. The double check valve is the minimum
requirement recommended by the Water Corporation to prevent any cross-contamination of mains water
and rainwater.
An example of a double check valve with brass ball valves
Preparation of plans for local council
A minimum fee of $220 is charged for the preparation of scale drawings and a written
submission to a local council for a rainwater tank system. This fee includes a site visit
where measurements of block size, house and other buildings size and location, distance to
boundaries, and position of tank, and overflow to subsurface trenches and/or garden beds
for drippers are taken.
It is very helpful if you can supply a plan of the house and block showing dimensions
and other details.
Should you require both a rainwater tank and a greywater system, the fee is greatly reduced.
However, the installation of a rainwater tank usually requires ‘building’ approval, while
a greywater system needs ‘environmental health’ approval. Essentially, two different
applications have to be written, although the same house and block plan can be used.
The written submission nominally lists the specifications for the proposed system and
brief notes about the system relevant to the application. Often, local government
councils require engineered drawings from the tank manufacturer, and these are supplied
as part of the submission to council.
A Building License is issued for the successful application for a rainwater tank.
For any greywater application, the completion of the “Application to Construct or
Install an Apparatus for the Treatment of Sewage” form is provided. In both cases,
these applications are either forwarded to the property owner so that they can submit
this to their local council or are submitted to council on your behalf. Any application
fees are the responsibility of the property owner, and these must be paid before any approvals are given.
Optional Extras
Every rainwater tank comes supplied with a basket (leaf) filter, tap (usually brass) and
overflow pipe. Each tank manufacturer has their own fittings, but generally the basket
filter is made from moulded plastic, the tap is either a simple stopcock or a gate valve,
and the overflow pipe is a length of PVC which directs overflow to the ground
Large steel-based tanks will also have a sacrificial anode which is buried alongside the tank.
This helps prevent corrosion of the steel body.
An example of a sacrificial anode before burial.
In addition to these standard fittings, a number of optional extras are available for your
rainwater tank system. These include:
- Filter bag – a 20 μm cloth filter which removes most sand and dust as the water enters the tank.
- Vermin proofing. This is often necessary for steel and steel-liner tanks to prevent insects,
frogs and small rodents from finding their way into the tank.
- Garden overflow. Either a subsurface piped trench or a simple gravity-fed dripper system is
installed to direct overflow more effectively to garden areas or beds
- Venting. Condensation is common is rainwater tanks. This is not a problem for poly (plastic)
tanks but can cause minor corrosion in steel and steel-liner tanks. A ‘whirlybird’ vent or similar
is installed in the tank lid to duct excess water vapour to the atmosphere.
Dripperline can be supplied or installed to enable excess overflow
from a full rainwater tank to be used to water garden areas.
