Fixing and Preventing Rainwater Tank Overflow Problems

Installing screening on your tanks is a necessity and council requirement to keep out mosquitos and insects from your tank. Yet, screening can introduce new problems that tank owners should be aware to. Without proper tank maintenance to clean out strainers and unclog screens, water might end up overflowing from the top of your tank and/or not overflowing into proper drainage.

Failure to perform simple screen maintenance can result in more serious tank water overflow problems that result in foundations being eroded away, or neighbours complaining about lots of water flowing onto their property during downpours.

Maintaining Your Rainwater Tank

It is important to properly maintain your rainwater tank to ensure a high-quality source of water. This is especially important if your rainwater will be used for showers or bathing, in cooking or for drinking. Yet, failure to maintain your water tank can also result in other issues.

Maintaining your water tank isn’t difficult and simply involves:

  1. Approximately every six months, general inspection of your roof, gutters, tank, entry points, strainers and the like. Cleaning out strainers and fixing any problems as necessary.
  2. Every 23 years, inspecting inside your tank to check on sediment build-up which accumulates as sludge at the bottom of your tank without a tank self-cleaning system.

Provided your rainwater tank has been properly installed with overflow correctly fed into your stormwater drainage, and you routinely perform tank inspections and maintenance, you should be able to prevent issues like water incorrectly overflowing from the top of your tank.

How to Fix Tank Overflow Issues

Often the biggest issue to fixing any problem is first identifying the cause of the problem. If your water tank is having overflow issues during downpours, then you will need to perform a little investigation. That said, two common causes of tank overflow issues include:

  1. Incorrect water inflow/overflow ratio – if you have several pipes feeding rainwater from your roof into your rainwater tank, then quite possibly water is flowing into your tank much faster than it can overflow from your tank. Your tank then fills up with water and starts overflowing from the top.This problem is a result of poor installation since the inflow/overflow rate wasn’t properly taken into consideration. We recommend consulting a fully-qualified plumber who is experienced with rainwater tank installations to work out a solution to this issue.
  2. Overflow strainer gumming up – it is important to keep mosquitoes and insects out of your tank, which is why overflow screens are installed. Sadly, the small holes in the meshing can gum from fine organic matter over time. Routinely inspecting and cleaning your strainers and tank screens can help prevent this.It is also important to understand that fixed strainers will reduce the overflow of water through them, and this should be taken into consideration when your rainwater tank is installed. Optionally, it is possible to install a screened “overflow flap valve” which remains closed and “flaps” open during downpours to let water out. You will however need to inspect them every so often to ensure that the springs keeps the flap firmly sealed.

If you have been experience water overflow issues from your rainwater tank, and this article has been able to help you, please share it online or mention us to your friends. Team Poly manufactures and sells a diverse range of water tanks including a range of round tanks, slimline tanks, underdeck tanks and underground tanks which meet and often exceed Australian standards.