Water tanks

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(Installation - Buried tanks & outlet valves)
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-'''Water Tanks'''+[[Image:Water tank round.JPG|right|thumb|Round water tank (12,500 litre) with pump]]
 +[[Image:Water tank under deck.JPG|thumb|right|Water tank (4,500 litre) under deck]]
-Connecting a water tank to the down spouts of your home's guttering system is one of the easiest ways to contribute to+Connecting a '''water tanks''' to the down spouts of your home's guttering system is one of the easiest ways to contribute to sustainable living.
-sustainable living.+
==Regulations as at May 2007== ==Regulations as at May 2007==

Revision as of 05:00, 21 December 2007

Round water tank (12,500 litre) with pump
Round water tank (12,500 litre) with pump
Water tank (4,500 litre) under deck
Water tank (4,500 litre) under deck

Connecting a water tanks to the down spouts of your home's guttering system is one of the easiest ways to contribute to sustainable living.


Regulations as at May 2007

  • In Canberra in the ACT, new developments must include a water tank.
  • In Sydney and NSW, new building regulations call for a 40% reduction in mains water usage.
  • In Victoria, new homes will have to be 5-star standard, and must install either a solar HWS, or a water tank.

Rules and rebate schemes are different in each state.

Info on Victorian Rebate Scheme

With the current low rebate schemes and the low cost of water the reasons for installing a water tank tend to be altruistic rather than financially motivated: for the cost of installing a 9000 litre tank, you can buy more than 5 million litres of water from Sydney Water.

Assessing your situation

So if it is not for financial reasons why are you installing a water tank?

Here are some reasons:

  • Do your part for water conservation
  • Be able to water your garden with some independence from water restrictions
  • Make rain water available for drinking in your home - see this info (PDF)
  • Use rainwater in the laundry and toilet

What size water tank should I choose?

Get the biggest tank you can fit in your garden. As a rule of thumb, about 25,000 litres (5,000 gallons) of storage is considered enough for a small family to be nearly self sufficient for normal domestic usage. The storage size will vary according to local rainfall. Dry areas would require more storage, wet areas less.

Types of Water Tanks

  • Cyclindrical tanks - either plastic or galvanised iron - are often the cheapest, but they require a lot of space
  • Rectangular and other narrow tanks - either plastic or galvanised iron - can fit under eaves and in narrow spaces next to fences. However, they are lower volume and more expensive.
  • Collapsible bladder systems can be installed under houses between existing stumps. However, these are the most expensive.

Other Considerations

  • If you use tank water for showering, be aware of the difficulties matching different water pressures. The mains pressure is often higher than what a pump can produce and the mains pressure can stop the tank water from coming through the pipes.
  • There are strict government regulations concerning the connection of mains water and tank water systems. The intention is to prevent tank water systems possibly contaminating the mains system. A licenced plumber must install this type of connection. These regulations don't apply if the systems are plumbed seperately.
  • The ability to fill tanks also depends on the roof catchment area you have. If the catchment area is too small you may never fill large tanks. This can be calculated from the average rainfall events for your location and the roof area.
  • In city areas use a green plumber. Many urban plumbers are not acquainted with installing and connecting rainwater tanks, systems and pumps.


  • Larger tanks will often need to be installed in back yards using a large crane to lift it over the house roof or back fence (if there is rear access).
  • Check with the tank retailer for the cost of using a crane. Some retailers will offer a free crane install for tanks over a specific size, below that size you may have to pay separately for the cost of the crane hire (which could be $300 to $500).
  • Tanks can be partially buried - up to a third the height of the tank is usually possible. If you bury tanks deeper than that without taking special measures they can "pop out" of the ground if the tank is empty and the water table rises. A drain system around a buried tank site with a sump and water pump installed could avoid this happening and enable the tank to more fully or completely buried. This type of installation should be done professionally.
  • Ensure that every tank has a valve installed at its outlet. This will allow you to isolate the tank quickly and easily to work on the pipe system. Also, if you damage the pipe outlet system you can shut the valve to prevent the entire contents of the tank being lost.
  • Tanks can be installed under decking if the decking support structure is designed to leave space underneath to accommodate the tank.\
  • All tanks must have an overflow connection to stormwater (or perhaps another lower tank).

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