Tank Overflow High Flanged | Store More Rainwater | Rain Harvesting

Tank Overflow High Flanged

Tank Overflows and Screens
Installing a Rain Harvesting Tank Overflow High Flanged is a super simple way to boost your rainwater tank’s capacity so you can store more water.
Size 90mm TATO12
Size 100mm TATO18
  • 90mm
  • 100mm

Boost your tank’s capacity

With their curved 90 degree bends, our high level tank overflow outlets raise the level at which your tank water begins to overflow. Every extra millimetre of water over a square metre gives you another litre of water in your tank. By adding up to 120mm to your tank’s capacity, this significantly boosts the volume of water you can store.


Store and use more water

By adding volume to your pre-existing tank you can store and use more water. The added capacity wastes less water during high rain periods and gives you more water to use around your property.

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 tank 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 holesaw. You should position the hole so that when your overflow is installed, the highest water level will sit below the level of the bottom of the tank inlet and/or tank inlet screen.
    2. Slide your tank overflow into the tank overflow hole so that the bend faces up inside the tank.
    3. If you have an existing tank overflow hole and doing this means the open end of the bend will sit above the level of the tank inlet and/or tank inlet screen, orient the bend diagonally or trim the top of the overflow.
    4. Apply silicone to the flange on your tank overflow, push it against the tank, then screw in place through the provided screw hole guides.
  • Maintenance

    When properly installed, your tank overflow should be maintenance-free.

    We recommend pairing your tank overflow 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 High Flanged
  • Tools you might need
    • Marker pen
    • Hole saw
    • Silicone
    • Screws
    • Screwdriver
  • Product FAQs

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

    1. Check that your tank screen is free from debris, ie. leaves, sediment
    2. Your tank outlet may be restricted by a blocked Mozzie Stoppa or another obstruction.
    3. Check your overflow outlet for the presence of an obstruction and remove.
    4. Alternately, the level of your tank overflow may sit above the base of your tank inlet.
    5. Check that the outlet pipe is equal to or greater than the combind capacity of the pipe feeding your tank inlet
    6. 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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