How to clean your Rainwater Tank

What is a rainwater tank and how does it work?

A rainwater tank is used to collect and store rainwater from your gutters. The water may later be used, through a pump system, to irrigate your garden or fill up your swimming pool, or it can be purified and connected to your mains for showering, cleaning and drinking purposes.

How does water get dirty inside your tank?

After a few weeks of sitting, protozoa, algae, bacteria and bloodworms start to develop at the bottom of your rainwater tank. This occurs faster when your tank is directly exposed to the sun or when the water from your gutter carries organic debris. Protozoa and bacteria include E.Coli and Giardia, which can cause serious health issues such as vomiting and diarrhoea. Bloodworms and mosquito larvae spread rapidly if insects are able to enter your tank through the overflow, for example.

Dirty water from rainwater tank
Bloodworms and sediments collected from the bottom of a rainwater tank

Empty and clean your tank manually

You can empty your tank and use a high-pressure hose to clean the inside, and then let it dry before you connect your tank back to your gutters. This is very time-consuming and can be dangerous as someone is required to enter the inside of the tank.

It is recommended that you do this once a year to every two years.

Use an automatic tank cleaner

A safer and more efficient way is to install an automatic tank cleaner. A tank cleaner is a system of pipes that siphons the water at the bottom of your tank every time it overflows. It effectively removes the water at the bottom 10cm of your tank that contains sludge, sediments and bacteria.

Tank and automatic tank cleaner

Tank cleaner siphoning water during rainfall

Benefits of a tank cleaner vs. manual cleaning

The main benefits of using an automatic tank cleaner are: 

  • Once you install your tank cleaner, you can set it and forget it, as it works automatically
  • No maintenance is required
  • Less water is wasted over time

Is cleaning your tank recommended when harvesting rainwater?

At EcoDepot we always recommend that you clean your rainwater tank regularly. It is also important that the water going into your rainwater tank is as clean as possible as it increases the quality of your water and limits the growth of unhealthy bacteria in your rainwater tank.

Automatic tank cleaner

How an automatic tank cleaner works 


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