Rainwater Tanks and Pumps
Teach your children about sustainability
Water usage, water conservation and rainfall calculations are excellent learning opportunities for children, and they can become lifelong advocates of responsible water usage.
So, where do you start educating kids about water?
To save water, you must know how you use water, so a household water audit is a great place to start. Once you know how you use water, you can identify ways that you can reduce water usage through changing your habits and simple conservation measures. A water audit is a simple and easy exercise that you can do with your children.
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Say hello to your water meter
Your water meter is regularly read by your water supplier, so it’ll be at the front of your property and easy to spot. Water meters measure the total amount of water used in your home and the standard Australian household water meter has black numbers and red numbers. Read the numbers from left to right. The black numbers represent kilolitres (1,000 litres) and the red numbers represent litres.
Look at your water bill
Most water authorities will calculate your daily water usage and include it on your bill. Your water bill reflects consumption measured in kilolitres, so multiply by 1,000 to convert to litres. If your water authority does not provide a daily average, take readings from your water meter a month or two apart, and calculate your total water usage by subtracting the previous meter reading from the current reading, then calculate your average daily usage by dividing the total usage by the number of days between readings.
Now you know how much water you use in total, the next step is to add some detail:
Estimate where you use the water
To determine how much water you consume in your home, it is necessary to measure water flow from each fixture in your house.
To calculate flow for taps (indoor and outdoor) and showerheads, turn the tap or shower on while holding a container under the tap for 10 seconds and measure the quantity of water in the container. Multiply the measured quantity of water by 6 to calculate usage in litres per minute.
To calculate flow for toilets, turn off the water supply to the toilet and mark the water line on the inside of the cistern. Then flush and refill the cistern with water using a measured container and measure the volume of water that is required to fill water back up to the water line mark inside the cistern and record this number. Repeat the process for half-flush and full-flush options. Turn the water on to the toilet to resume normal use.
If your appliances such as washing machines and dishwashers are relatively new, you may be able to obtain the water usage per cycle from the manufacturer’s specifications. Alternately, you can simply read your meter before and after using the appliance.
Calculate your water usage
Finally, estimate how many times per day or how many minutes per day you use each fixture or appliance. Multiply the water flow per fixture by the minutes per day the fixture is used and multiply the usage for each appliance by the number of times the appliance is used each day.
You will also need to estimate the amount of time the tap runs for general usage such as filling a kettle, washing dishes, cooking, watering the garden, topping up the pool etc.
Download a Water Audit Table < here >
The benefits of adding a rainwater tank
A rainwater tank is a store of water that you can use instead of mains water.
Calculating how much rainwater you can collect is straightforward, but you’ll need to know the catchment area that supplies your tank. The catchment is simply the portion of your total roof area that rain falls on before draining, via the gutters, into your rainwater tank.
Every millimetre of rain that falls on every square metre of catchment will deliver 1 litre of water into your water tank. If you have a catchment of 125 square metres and you get 18mm of rain, 2,250 litres (125m2 x 18mm) of water will flow into your rainwater tank.
When you consider that average annual rainfall in Sydney is over 1,100mm, you can see how much water you can collect, and how much mains water you can substitute with rainwater.
If you install a water level detector on your rainwater tank, it provides a visible reminder of the additional water you have collected.
Estimate your potential savings
Now you understand how water is used in your household and how much rainwater you can collect, you can see whether your household can adopt better practices to reduce the amount of water that you use and where you can substitute mains water with rainwater.
This might include not letting the water run needlessly when washing dishes or brushing teeth, taking shorter showers, collecting water in showers and fixing leaking taps, or using drip irrigation systems, buried soaker hoses or watering, topping-up the pool and car washing with rainwater.
Financial benefit
Water usage and water substitution is not only a good exercise in sustainability for children, but it has also real financial benefits as well.
If a household of four people uses 1,000 litres per day, and they can reduce average usage to 175 litres per person, that is a saving of 300 litres per day or almost 110,000 litres per year. At a typical cost of $2.35 per kilolitre, that equates to savings of about $260 per annum.
Remember that the water minimisation efforts of multiple household’s ripple outwards to:
+ protect remaining environmental flows in rivers.
+ reduce infrastructure operating costs, and,
+ decrease stormwater runoff, thereby helping to reduce local flooding and scouring of creeks.