Removing Sludge From Your Water Tank

If you collect rainwater for drinking or cooking purposes, you’ll know the importance of keeping your water tank well-maintained. Not only does regular maintenance ensure the water remains top quality, it enables the tank to continue functioning at its best. One common factor of owning a water tank affects water quality and tank performance is the formation of sludge. No one wants to drink or cook with sludge-filled water, so let’s look at how to remove the build up from your tank.

How Does Sludge Form?
First, let’s look at exactly what sludge is, and how it forms.

Essentially, sludge is the result of the decomposition of materials that find their way into your tank. These materials might include anything from organic matter (bugs, leaves, animal waste) to dust, debris and sediment. Your tank may have all the necessary covers, strainers and leaf catchers to minimise the volume of materials that get inside, but the likelihood is that materials will make it into the tank and into the water. As those materials decay they form a sludge that settles at the bottom of the tank, as well as a thin biofilm layer at the top of the water.

How To Get Rid Of The Sludge
The CSIRO recommends having a licensed contractor desludge your tank every two or three years. If you wish to attempt it yourself though, there are numerous ways to clean sludge out of a tank.

● You can empty out the tank of any water and then hose and sweep out the tank from top to bottom. Just make sure you don’t allow the sludgy water to drain away through the sewer system – scooping up the sludge and safely disposing of it in the waste is best.
● If you don’t want to empty your tank, the Australian Government’s Guidance on Use of Rainwater Tanks suggests siphoning the sludge with an inverted funnel attached to the end of a hose and carefully sweeping it across the bottom of the tank. You can then dispose of the sludge into the waste.
● Installing a cleaning pump to extract the sludge from your water tank might be a more workable solution. It can be an expensive option though, especially if you’re only putting the tank through the desludging process.

Effective Water Tank Preventative Measures
If you want to reduce the amount of materials that might get into your water tank, prevention is the best measure. There are numerous ways to reduce the likelihood of sludge forming in your tank before removing it even becomes a necessity.

These include:
General rainwater tank maintenance (including checking for leaks, cracks and holes)
● Installing mosquito mesh protection
● Installing first flush water diverters
● Keeping your gutters clean, and
● water pump maintenance

Removing sludge from your rainwater tank can be a messy process. However putting your tank through a ‘desludging’ every two to three years will ensure your water remains clean and healthy, and your tank remains in prime condition.