Rainwater Tanks - Rain Water Tanks

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Rain Water Tanks

In a changing environment the security of our lifestyles can be protected through
the simplest of forms, such as a water tank. Water tanks are a cost effective way
to provide for back-up supplies to households during water restrictions, reduce
your dependence on public and environmental water supplies and reduce your
excess water bills.

When purchasing a tank there are several considerations to be assessed,
including what purpose will this new water supply be allocated to, the holding
capacity of your new tank, what is the preferred design, placement and type of
tank best suited to your situation and what maintenance regime is required to
ensure water quality and the health of your family. Here are some tips for

NSW Health Department

The NSW Health Department suggests that in urban areas public water supplies
remain the most reliable source of good quality drinking water for the community,
with rain water tanks being utilised for non-drinking uses such as flushing toilets,
washing clothes and outdoor purposes such as swimming pools, watering gardens
and washing cars. This is due to public water supplies are filtered, disinfected,
generally fluoridated and monitored.

The main issues that the NSW Health Department are concerned with are
potential microbiological and chemical contaminations of the rainwater catchment
area. With these concerns being considered there are several management
techniques which can be utilised to minimise the risk of rain water being

Contamination Risks

   -   organic material & treated wood products
   -   contaminated roof catchment area from vehicle exhausts, local factories,
       grade of pipe infrastructure, initial installation of tank
   -   exposure of tank water to light
   -   lead based paints and lead flashing
   -   acrylic paints as they may contain dissolved detergents and chemicals
   -   bitumen-based materials
   -   mosquitoes / vermin

Water Tank System Management & Maintenance

Through the correct installation / design of rain water tanks and proper
maintenance of the water tank and its catchment area you can maintain high
water quality.

Installation Considerations

          Use only high quality piping and fittings made of drinking water grade
           materials not storm water grade materials.
          Has your tank been flushed with clean water after the manufacturing
          Have precautions been taken to ensure that minimal light has access
           to the water in your tank. This may include the proper sealing of tank
           inlets and outlets.
          Your tank should be mosquito and vermin proof, with the inlets and
           outlets of your tank having secure covers and mesh strainers.
          Avoid catchment areas of roofing that include discharge flues from
           wood fires, kitchen exhausts, air conditioners and hot water systems.

Local Planning Regulations

When installing a Rainwater tank larger than 10,000L or are applying a variation
of the plumbing system a development application form is required by Council.
Your can access the Landuse Application Form & Guide through / Planning & Development / Application Forms.

The main issue that Council is concerned with is how the location of your rain
water tank will affect your neighbours, especially with regards to where the over
flow pipe is located and potential erosion problems.

First Flush Devices

The installation of first flush devices will prevent the first portion of roof run-off
from entering the tank therefore reducing the amount of dust that may have
accumulated on the roof from being washed into rainwater tanks. Disconnecting
tanks to prevent the first flush of the roof surface from entering the tank can also
be considered to reduce the amount of contaminants from entering your water

Gutter Management

Gutters should have sufficient and continuous fall to downpipes to prevent the
pooling of water. Stagnant water could encourage algal growth and possibly
provide a site for mosquito breeding. A fall of one in 100 should be sufficient.

Gutter Guards may help you maintain your homes gutter system and tank water
quality by not allowing plant material and vermin to enter your gutters and help
in making your home bush fire safe.

Maintenance Regime

          Roof Catchments - Regular inspection of gutters to clear debris,
           remove over hanging vegetation and regularly clean all tank screens.
          Managing Mosquitoes – refer to next section
          Sludge Removal – Tanks should be examined every 2 to 3 years for
           the build up of sediment and plant material and the bottom of the
           tank. This sludge can be removed through siphoning the bottom of the
           tank or completely emptying the tank. Employing the services of a
           professional tank cleaner may be the best choice with confined space
           issues, tank movement concerns and other safety issues to be
          Disinfecting tank water is not generally necessary unless you expect
           that the water is contaminated or you have been advised by your
           doctor. Water filters can be installed at drinking points. For guidelines
           visit NSW Health Department site Rainwater Tanks guidelines.


Rainwater tanks can provide excellent habitats for mosquito breeding. In addition to causing
nuisance, certain types of mosquito can be vectors of arbovirus. This is an issue in Sydney
Regions and the Illawarra with Ross River and Barmah Forest viruses possibly being
transported by the mosquito species Ochlerotatus notoscriptus (formerly Aedes notoscriptus)
The symptoms of these viruses are mainly rheumatic affecting the joints and presenting flue
like symptoms.
Mosquito borne disease may become more common in Australia due to rising
temperatures and humidity’s associated with climate change. The Commonwealth
government’s enHealth web site provides an additional guide to rain water tanks
with information on mosquitos in sub-tropical areas of Australia.

By far the preferred approach for managing mosquitoes and other insects is to
keep them out of tanks. In addition, rainwater should not be allowed to pool in
containers or on surfaces below tank outlets or taps, as this can also provide a
breeding site.
Unless in use, all access points, excluding the inlet and any overflows, should be
kept shut with close fitting lids that will prevent mosquito access. Inlets and
overflows should be covered with closely fitting removable insect-proof screens.
Detection of mosquito larvae (wrigglers) in rainwater tanks indicates the presence
of an opening through which the female mosquito can enter and lay eggs or the
entry of eggs laid in ponded water collected in roof gutters.

Mosquito Larvae Chemical Treatments

As a last resort, tanks can be treated by adding a small quantity of medicinal or
liquid paraffin or domestic kerosene. The recommended dose of kerosene is 5 mL
or one teaspoon for a 1 kL tank up to 15 mL or 3 teaspoons for a 10 kL tank.
When using paraffin the dose should be doubled. These additives will eventually
evaporate after they have restricting the air supply of mosquito larvae.

Note: Commercial or industrial kerosene’s, for example, power kerosene for
tractors etc., should not be used in rainwater tanks. Commercial and Industrial
chemicals can cause degeneration of the polymer coating in tanks and should not
be used.

Eligibility of Rebates

A rebate for your water tank can be acquired through both Federal and State
Government applications. The total sum of the rebate payments cannot exceed
the total cost of the rainwater tank(s). If you install more than one tank it is the
combined water holding capacity that counts toward rebate eligibility.

Federal Government Rainwater Tank & Greywater System

For application guidelines outlining suitable products under the rebate system and
a rebate application form please follow this link.

The available rebates through federal Government are:

Rainwater Tank(s) capacity – must be plumbed in for indoor                   Rebate
water use by a licensed plumber
2,000 litres – 3,999 litres                                                  $400
4,000 litres or larger                                                       $500

Greywater System – must be installed by a licensed plumber                   Rebate
Permanent Greywater treatment system                                         $500
 (As of 3 March 2010 link)

State Government Rainwater Tank Rebates

From 15 January 2010, the total NSW Home Saver Rebates a household can
receive must not exceed $1500 per property.
If you receive a water bill from Sydney Water for your application for the State
Government rebate must be done through Sydney Water. Otherwise you apply
through the NSW Home Saver Rebates Rainwater Tank Rebate Application Form.

The requirements for this rebate are listed below.
          The tank(s) must have a minimum 2,000 litre capacity and be
           purchased in full and installed between 1 July 2007 and 30 June 2011
          Households not connected to the mains supply are eligible for a
           rebate for the purchase of the tank only.
          Rainwater tanks installed to comply with BASIX (the Building
           Sustainability Index, check with your supplier) for new homes, major
           renovations or a pool installation are not eligible for a rebate.
          Limit of one rainwater tank rebate per property.

Tank(s)         Tank Rebate     Connection       Connection      Maximum
capacity                        to toilet(s)     to Washing      Total Rebate
2,000-3,999       $150           $500            $500             $1,150
4,000-6,999      $400            $500            $500             $1,400
7,000 litres     $500            $500            $500             $1,500
and above
 (As of 3 March 2010 link)

For more information about applying for the rainwater tank rebate, call the
Environment Line on 1300 361 967 or email


Federal Government
Department of the Environment, Water, Heritage & Arts

State Government NSW Rainwater Tank Rebates
Department Environment, Climate Change & Water
NSW Home Saver Rebates

Sydney Water (State Funded) Rainwater Tank Rebate terms / conditions
and application form

Commonwealth Governments Sustainable Homes Guide

NSW Health Rain Water Tank Guide

NSW Code of Practice for Plumbing & Drainage

enHealth Commonwealth Government RainWater Tank Publication

Australian Government Department of health & Aging

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