Protect the tank from overfilling and draw away harmful sediment build up.

  • Overflow outlets stop the tank from exceeding capacity
  • Add an insect screen for bug protection
  • Vacuum kit draws away sediment from the tank bottom every time the tank fills to capacity
  • Anti syphon device in vacuum kit prevents tank draining



Why Marley?

15 year guarantee

We stand by our product, and back it for 15 years

Will not rust / corrode

Designed for NZ’s salt-laden coastal air

UV resistant

UV resistant to handle NZ’s harsh summer sun, high UV levels and long, hot days

100% Recyclable

Used spouting and downpipes can be returned to Marley for recycling

Made in NZ

Proudly made in New Zealand for over 40 years



Overflow Outlet (90mm)
Plastic, Fibreglass, Flat wall tank


Overflow Outlet (90mm)
Concrete tank


Insect Screen (90mm)


Vacuum Kit (90mm)*
Plastic, Fibreglass, Flat wall tank


Vacuum Kit (90mm)*
Concrete tank


*90mm Stormline pipe sold separately



Technical Details

Tank Vacuum Kit

Fine sediment, which can contain harmful bacteria and heavy metals, eventually builds up in the bottom of rainwater tanks. It is important to maintain the tank to prevent this sediment being drawn out through the outtake pipe for use.

A Tank Vacuum System automatically vacuums the sediment off the bottom of the tank in the area of the outtake pipe every time the tank overflows. The systems are supplied in kit form and fit all types of tanks, including metal, plastic, concrete and fibreglass.

When water flows into the tank and the tank fills, the excess water escapes via the tank overflow outlet, but with a tank vacuum system, the water enters the interior siphon pipe “D” at the bottom at point “E”.

As the excess water rushes up “D” it draws the sediment off the bottom of the tank like a vacuum cleaner. The water that is siphoned to waste is from the “Anaerobic Zone”, which is the worst quality water. With a standard overflow outlet, water from the top of the tank (the best quality water) goes to waste.

An anti-siphon device in the elbow at the top of the tank “C” prevents the exterior overflow pipe “F” from siphoning water out of the tank. “F” is best fitted with a Tun dish or rain head under the tank overflow outlet. The outlet can also be fitted with an insect proof Flap Valve that also prevents siphoning.

Normally tanks have an outtake point at “A” which draws the water from the Anaerobic Zone which is the poorest quality water in the tank. Where possible fit another outtake point 250-300mm above the bottom of the tank “B” so that better quality water is drawn for use from the Aerobic Zone.


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