To protect the quality of water in your rainwater tank you will need to use screens and strainers to filter out debris, insects and mosquitoes. This article looks at the types of screens and strainers you can install on your tank to help keep your water clean.
Rain Heads (Leaf Eaters)
Rain heads, also known as leaf eaters, are a PVC head piece often installed at the top of the downpipe that leads water into your tank. As rainwater flows down a roof and into the gutters it often collects leaves which then get washed into the pipework leading to your tank.
To stop leaves from entering the piping that leads water into your tank, you can install a rain head at the top of a downpipe just below your gutter. The rain head has a screened opening that allows water to pass through while deflecting leaves and debris away. They also help to keep mosquitoes, frogs and vermin out of your pipe system.
Leaf Strainers for Tank Inlets
Located on top of your rainwater tank will be a round hole about 200mm to 500mm in diameter. The pipe work from your gutters lead rainwater to this opening which then flows into your water tank. If you leave this opening unscreened then leaves, debris, mosquitoes, frogs and the like would enter your water tank. Leaf strainers provide a simple and effective solution to stop this from happening.
The size of strainer that you will need varies based upon your tank model and size. Your leaf strainer should be tightly fitted for proper protection. The size of holes in your tank’s strainer should be less than 1mm to prevent mosquitoes getting in.
Located at the top on your tank wall is a round hole wide where an overflow pipe is connected to. Your tank’s overflow pipe is another way insects and vermin can find their way into your tank if left unscreened.
To protect against creepy crawlies, mosquitoes and frogs climbing up your overflow pipes and making a home in your tank you will need screening. Team Poly sell a 90mm overflow strainer and elbow that you can easily connect to your PVC pipe to protect your tank’s overflow against entry.
Protecting Against Mosquitoes
Throughout Australia, mosquitoes can be found in every state and will rapidly breed where there is an open fresh water supply. Rainwater collecting in pot plants and trays, buckets and the like create fertile breeding grounds. A water tank that isn’t properly screened is just asking for trouble.
When purchasing a strainer or screening, the aperture size (holes) on the meshing need to be less than 1mm to stop mosquitoes. They should also be made of stainless steel to prevent holes developing through corrosion.
If you notice some mosquitoes already buzzing around inside your tank, then you can add a small amount of domestic kerosene or liquid paraffin. The Department of Human Services in Victoria recommend one teaspoon of domestic kerosene in a 1,000 litre water tank or 3 teaspoons in a 10,000 litre tank (double these amounts if you use liquid paraffin). Do not use industrial or commercial kerosene, and you should verify ensure adding these substances are alright for your tank.
Screening rainwater tank is not expensive or difficult to do, and many states and councils require it. Given they form an important function, Team Poly includes inlet strainers and overflow screens with most poly water tanks.