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Tank Overflow Flanged

Tank Overflows
Manage overflowing water and make it easier to connect standard plumbing fittings and mosquito-proof screens to your tank outlets with a Rain Harvesting Tank Overflow Flanged tank outlet.
Size 50mm TATO62
Size 90mm TATO29
Size 100mm TATO22
  • 50mm
  • 90mm
  • 100mm

Boost your tank’s capacity

Effectively manage overflowing water during light or heavy rain events and make it easy to connect standard plumbing fittings to your tank with our flanged tank overflows.


Store and use more water

Made from UV-stabilised UPVC for longevity, our tank overflows are available in a range of sizes and with a flanged fitting to suit your tanks and stormwater pipes.

Tank Overflows provide additional security for your tank’s connections, and allow you to effectively manage overflowing water. Tank Overflows also allow you to increase your water tank’s storage, enabling you more ability to plan for volume.

Learn more about the 4 pillars of designing a Rain Harvesting system. 

The Rain Harvesting steps addressed:

Limit sources of contamination     Plan for volume

Filter leaves and debris                    Divert the first flush

Secure the system                             Manage standing water

Consider a safety net                        Monitor and maintain

  • Specifications

  • Installation
    1. If you do not have an existing tank overflow hole in your tank, use your overflow as a template to mark the size of the hole you need to cut in the side of your tank, then cut using a hole saw. Ensure that the bottom of the hole you cut sits lower than the bottom of the tank inlet and/or tank inlet screen.
    2. Apply silicone to the flange on your tank overflow, push it into the tank overflow hole, then screw in place through the provided screw holes.


  • Maintenance

    When properly installed, your Tank Overflow Flanged should be maintenance-free.

    We recommend pairing your Tank Overflow Flanged with a mosquito-proof screen or flap valve to prevent mosquitoes and other pests entering your tank through the overflow outlet.

  • What's in the box?
    • Tank Overflow Flanged
  • Tools you might need
    • Marker pen
    • Hole saw
    • Silicone
    • Screws
    • Screwdriver
  • Product FAQ's

    My tank is overflowing at the inlet rather than the outlet. What should I do?

    Check that your tank screen is free from debris, ie. leaves, sediment
    Your tank outlet may be restricted by a blocked Mozzie Stoppa or another obstruction.
    Check your overflow outlet for the presence of an obstruction and remove.
    Alternately, the level of your tank overflow may sit above the base of your tank inlet.
    Check that the outlet pipe is equal to or greater than the combind capacity of the pipe feeding your tank inlet
    If a Mozzie Stoppa is installed, remove, inspect and clean if necessary before reinstalling it at the outlet or replacing with a Mozzie Stoppa Easy-Clean.

    If your inlet/overflow issue persists, remove your tank screen and check for floating debris on the water surface. Floating debris such as sworf from the tank installation process’ may be blocking the Mozzie Stoppa during overflow and drifting away from the overflow when overflow has stopped.

    Should I choose a regular tank overflow or a high level product?

    High or extra high tank overflows offer a simple and effective way to increase your tank’s storage capacity.

    Whichever tank overflow product you choose to use, your overflow needs to sit below the base of your tank inlet screen. The advantage of the high level overflow is that it raises the maximum water level within the tank.

    What size should I choose?

    The diameter of the overflow must be equal to or larger than the diameter of the inlet pipe.

    Do I need silicon to seal my overflow to the tank?

    You can choose to use a gasket or silicon to seal your overflow to your tank. Silicon is not required if you use a gasket. All our tank overflow kits come with a gasket.

    Do I need a gasket to seal my overflow to the tank?

    You can choose to use a gasket or silicon to seal your overflow to your tank. A gasket is not required if you use silicon. All our tank overflow kits come with a gasket.

    Which way should I orient my high level overflow?

    The bend on your high level tank overflow should face up towards the top of your tank in order to increase your tank’s storage volume and overflow height.

    Can I install my high level overflow sideways?

    Yes. We recommend installing your high level overflow with the bend facing directly upwards, however, it can also be installed on an angle to adjust the upper level. This may be necessary to ensure the overflow level stays below the base of your tank inlet and/or tank inlet screen.

    How do I connect two tanks?

    When connecting two tanks, it’s best to connect them at the base with a balance line. It is important to ensure that the tank receiving water from the roof or other catchment area has an overflow outlet.

    Should I mosquito-proof my tank overflow outlet?

    Yes, it is important to mosquito-proof your tank outlet to keep mosquitoes and other pests out of your rainwater system. You can do this using a mosquito-proof tank outlet screen such as a Mozzie Stoppa Easy-Clean. All our tank overflow kits come with a mosquito-proof Mozzie Stoppa screen.

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Maintenance Tray
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300mm or 400mm

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