A water butt or rainwater tank is an essential part of any rainwater harvesting system. Practical and easy to install, these tanks can be used to water your garden whenever you like without having to rely on your mains supply. This makes them both economical and environmentally friendly.
Rainwater tanks and water butts are rarely used to supply water indoors due to their small volume. However, they can be really practical for the following applications:
- watering the lawn, garden or flowerbeds;
- watering a small orchard or vegetable garden;
- cleaning the car and your gardening tools.
Rainwater harvesting systems are often easy to install. A water butt or rainwater tank:
- does not require you to make any major alterations your existing rainwater drainage system;
- can be connected directly to the downspout;
- collects rainwater from your roof with the majority of run-off water directed into the tank;
- redirects any excess water back through your downspout when the tank is full.
Furthermore, these tanks:
- feature a capacity of 200 to 2,000 litres (or more, depending on the manufacturer);
- are made of polyethylene which is a lightweight material making these tanks easy to handle;
- come supplied with a filter designed to be fitted at the head of the tank. A leaf guard is usually fitted at the top of the downspout to prevent leaves from getting in the tank.
- are equipped with taps to distribute the rainwater collected by the tank. These systems usually rely on gravity to send the water down to the tap.
Depending on model and size, a water butt or tank may feature:
- a two inch (2") threaded connection to accommodate a tap or drainage plug;
- a submersible rainwater pump in the bottom of the tank to connect a pressure washer or garden hose;
- a pump with a level gauge used to stop the flow of water once the bottom of the tank has been reached. The pump power and flow rate should be chosen to match the capacity of the tank.
In order to choose the correct tank volume, you'll need to think about your own requirements:
- a minimum volume of 1,500 litres is usually recommended;
- consider that you'll need an average of 15 l/m² to cover basic gardening needs and calculate the tank volume to match the size of your garden.
Rainwater harvesting systems can be used to meet a variety of everyday water needs for tasks like watering, drainage and cleaning. Economical and environmentally friendly, a good water butt or rainwater tank can help you make big savings on a metered water bill.