In Australia, states require you to screen all entry points to on your rainwater tank. In Queensland, local councils may fine you several hundred dollars for failing to screen your tank. South Australian government advise when planning for rainwater use, the inlet and overflow of the rainwater tank must be fitted with mosquito proof, non-degradable screens to ensure continual rainwater tank water quality. This article covers the common entry points on your water tank and why screening them is important.
Water Tank Entry Points
When getting a rainwater tank there will be several points of entry (i.e., holes) in the tank which, if left unscreened, could allow insects to crawl into your tank. These include:
- Tank Inflow – the hole in the top of your tank where rainwater flows into your tank.
- Tank Overflow – the hole located on the upper wall of your tank which allows rainwater to overflow and be directed through pipes generally into a stormwater tank or property stormwater drainage.
- Tank Outlet – small hole located on the lower wall of your tank where a valve is attached allowing water in your tank to be accessed.
Why it is Important to Screen Tank Entry Points
Any hole in your tank poses a risk of entry for mosquitoes, insects, frogs, rodents and the like. Consider if rainwater just flowed through an open 30-40cm hole in the top of your tank? You would have leaves and debris blowing into your tank, mosquitoes buzzing and laying eggs, possibly frogs swimming around, maybe a few tadpoles.
Without secure and adequate tank screening, the quality of rainwater would obviously become very poor and even putrid, not to mention the health issues increased mosquitoes can cause in areas are obviously undesirable.
Thankfully, the solution is quite simple and inexpensive. To protect water in your tank generally means screening the three tank entry points above:
- Screening your tank inflow with a strainer,
- Protecting your tank overflow with screening either at the tank entry point or in the connected overflow piping, and
- Ensuring your tank outlet is fitted with a one-way valve.
To prevent mosquitoes, it is important that the aperture (holes) in your screening is 1mm or less and made of a quality stainless steel considered non-degradable.
For more information on screening your rainwater tank please read over our article, Properly Screening Your Rainwater Tank.