Calculating Your Family’s Water Usage Needs When Buying a Tank

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Calculating Your Family's Water Usage Needs When Buying a Tank

When looking to install water storage it pays to know how much rainwater your home can harvest, as well as how much water your family consumes. This article will also explore different areas to consider, to better estimate your family’s water usage and decide on how much water storage is ideal.

Average Australian Household Water Usage

In Australia, the average suburban home uses about 20,833 litres per month (250,000 litres of water per year). Unless running a “water tight” ship in your home, one person will on average consume 9,000 litres per month (300 litres per day). Owning a swimming pool that needs topping up, can make usage run much higher especially during the months of Summer.

This is probably one reason why our 5,000 gallon (22,500 litre) tank and 5,400 gallon (24,500 litre) tank outsell all other sizes. This size tank is one of the most competitive sizes in the industry, meaning you are bound to get the best price per litre on them. Our manufacturing facilities literally run hot moulding this size tank every day of the year. If you want to “cheat” on calculating, you likely won’t go wrong with this size tank provided your property has the space.

Calculating Home Water Usage

If you wish to have a better understanding of your water usage, one way it to look over your water utilities bills and average out how much water your household consumes. Another other estimation method is to calculate the main water usage areas in your home.

National Poly Industries provide an online water usage calculator to help you calculate water usage. It divides the water usage areas up into “inside” and “outside”, and different areas where water is often consumed.

Inside Water Usage

The main areas water is consumed inside the home is with showers and baths, dishwashing, laundry and toilet flushing. We estimate the following water usage figures:

  • Shower: 10L per minute (1 person = approximately 8 minutes)
  • Bath: 150L per tub fill
  • Dishwasher: 30L per load
  • Front Load Washing Machine: 80L per load
  • Top Load Washing Machine: 100L per load
  • Brushing Teeth (tap running): 5L per minute (1 person = approximately 2 minutes)
  • Drinking/Cleaning/Cooking: 10L per day per person
  • Hand Basin: 5L per use (approximately 1 minute)
  • Toilet Flush (single): 6L per flush
  • Toilet Flush (half): 3L per flush

Outside Water Usage

The main areas where water in used outside your home is normally with gardening, topping up your swimming pool, watering hard surfaces and car washing. This differs home to home, family habits and whether you have lush gardens or a swimming pool.

  • Garden watering (hose): 15L per minute
  • Drip System: 6L/hour
  • Car Wash: 200L per wash
  • Hosing Hard Surfaces: 15L per minute
  • Swimming Pool Water Loss: Surface Area * .125 * 100 (assumes 12.5cm water loss per day)

Evidently, there are many other areas where you might use water, but the above will serve to provide you with a reasonable estimate of your home water usage.

Once you have decided upon how much water you wish to store, check out National Poly Industries’ range of rainwater tanks. Our tanks are certified to Australian Standards, make use of food-grade polyethylene and sport SUPA-UV protection. In addition to a high-quality tank, we also aim to provide very competitive prices. Don’t hesitate to request a quote or pick up the phone.