Before making your final decision consider the following:

  • Carefully measure the space where you are going to place the tank. Don’t be afraid to ask some one to help with the measurements as it is critical to get them right. A mistake with the measurements can prove costly later on. Measure the available width allowing sufficient space for a person to pass between the tank and the fence once it’s installed. Measure the available length, checking to make sure the tank won’t obstruct doorways, windows or external air conditioners tree trunks or other obstacles;
  • If sitting the tank next to the wall of the house, measure the height under the eaves to ensure you have plenty of room to fit the tank. Remember to leave sufficient space between the eaves and the top of the tank so you can connect the tank to the spouting with an appropriate filter and first flush device (if required);
  • If you are connecting the tank to the toilet, try and locate the tank next to the down pipe closest to the toilet. This will reduce the amount of piping required and help keep your plumbing costs down;
  • Having decided where to locate the tank, work backward from the site to your front drive checking to see if you have room to move your tank to its desired location. Check for narrow paths, gateways, outdoor obstacles and overhead obstructions. You may need to reduce the size of your tank to ensure it will fit. Remember, provided you have sufficient space, you can always join a couple of smaller tanks together to increase your capacity;
  • Will you be connecting a pump to the tanks or use gravity/buckets to water your garden? A pump should be fitted by a qualified tradesman and will require a weatherproof external power outlet to be installed



Consider the size of your water tank and your needs – WATER CAPACITY

It is sensible try to select the largest possible tank capacity for the available area. In rural locations, space is not always a problem and so a traditional round tank is usually the most cost effective solution. However, in residential areas space can be a real problem, particularly if you are limited to locating the tank down the side of a house or in a small backyard and so a slimline tank may be more practical.

Your catchment area is calculated as:

1 sq metre of roof x 1mm of rain = 1 litre of water

For example, if your roof catchment near your tank is 20m x 8m = 160 metres x 1mm rainfall will equal 160 litres of water. 

Rainfall date is available on the internet. ie Melbourne is as follows:

January – 35mm, February 50mm, March 40mm, April 140mm, May 25mm, June 18mm, July 25mm, August 75mm, September 100mm, October 80mm, November 45mm, December 65mm.

Water catchment in Melbourne based on 20m x 8m for January is 5,600 litres

Things to think about:

 Water usage per person – Estimated water usage per person per day is 200 litres. Only consider this if you are wanting a full house water supply.

Toilets – Most newer cistern is approx 10 litres per flush.  Assume there are 4 people in the house flushing the toilet 4 times each per day – this is 160 litres per day or 4800 litres per month.

Laundry – Top washing machines use approx 120 to 140 litres per wash. Front loaders use approximately 60 to 70 litres of water per wash.  Calculate this over a month based on your households usage.

 Car – Washing a car takes approx 20 litres per minute.

 Garden – Watering your garden takes approx 20 litres per minute.  If you water your garden for half hour each week, this translates to 2400 litres per month