Water tanks are a great way to make use of one of the most essential and precious natural resources we have: rainwater.
Even moderate rainfall provides a lot of water that can be used to water your garden, wash your car, or even be drank, because one millilitre of rain falling on one square metre of roof equals 1 litre of water that can be collected.
When you consider that the average roof size is 160 square metres and Brisbane gets approximately a metre of rain a year, this is a lot of water that you can drink or water your garden with (about 160,000 litres). This has the potential for a family of three to collect enough water for household use for almost a year because the recommended usage for a family of three people is about 450 litres per day. If you multiply that by 365 it comes to 164250 litres for the year.
If more people collected rainwater off their roof then this would reduce the need for governments and councils to build dams and they could potentially help to reduce flooding because less water would run into storm water pipes during downpours.
Important points to remember when installing a rain water tank include:
- Take a good look at your roof and think about what it’s made from and how old it is. For instance, do you really want to collect water off an unsealed asbestos roof, or one that has lead flashings, or might be painted with lead paint? Paint with lead in it was frequently used up until about 1970.
- Gutters are built to allow water to flow into downpipes and so you can’t just cut a hole in your gutter anywhere that suits you and run a pipe into your tank because this would interfere with the flow of water. Instead, place your water tank under an existing downpipe, or run the existing downpipe to the tank.
- An overflow pipe must run from the tank into your stormwater pipes for times of heavy falls, or when your tank is already full and it is still raining.
- If you want to use the tank water for drinking you must have exceptionally good fall in your gutters so that water does not lie there for any length of time. Water that sits in the guttering for any length of time before it is pushed into the tank during a downpour is not good for drinking due to bacteria that like to live in warm, stagnant water, causing waterborne diseases.
- Another good reason for having good fall in your gutters right into the tank is because pooling water gives mosquitoes a place to lay their eggs. This is a general point for good health since mosquitoes can carry a number of diseases, as well as making outdoor living a trial instead of a pleasure.
- If you live in an area where there is a lot of air-borne pollution, or crops are top-dressed or sprayed with fertilizer or poisons, you might want to consider how you use the water you collect.
- Gutters and all pipes leading to the tank must be kept very clean if you want to use the water for drinking. Gutter guard, or something similar should be considered to help keep leaves and other debris out of the tank filters so that their cleaning is less arduous.
- Make sure that the systems that catch twigs and dirt are cleaned regularly because if they are blocked, they can cause water to stagnate when there isn’t a lot of rainfall.
People have been collecting rainwater for centuries and so if you decide to use this natural resource, you are joining an age-old tradition. It’s just so good that today we can do it in a safer fashion.