Frequently Asked Questions - Gutter Pumper

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Stop Gutter Overflows
Supa Gutter Pumper

Supa Gutter Pumper

- a journey with water -

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Gutter Pumper STOPS gutter overflows
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Frequently Asked Questions

Gutter Pumper Frequently Asked Questions

Q. What is the Gutter Pumper made of?

A. Gutter Pumper is made from U.V. resistant ASA; a tough recyclable plastic that has superior resistance to outdoor exposure and ageing.

Q. Why are there 2 versions of the Gutter Pumper?

A. The original Gutter Pumper (Hi-Flow) was based on the syphonic outlets used in the Supadiverta and has the same 2 vertical uprights supporting the baffle. This design had some potential customers questioning whether the large aperture could result in debris being trapped. Whilst Aquatrek did not have any blockage problems during prototyping or field testing, it was later decided to redesign the baffle support to incorporate a cage made of multiple vertical uprights to allay any user apprehension. Both versions are in wide spread use, neither suffer blockage issues and the Hi-Flow moves 8% more water when primed.

Gutter Pumper Hi-Flow
8% higher flow rate than standard Gutter Pumper
Gutter Pumper
Quieter in operation

Q. How hard is it to fit a Gutter Pumper?

A. A 32 mm hole is drilled in a flat bottom eaves gutter. The Gutter Pumper is fitted into the hole, connected to 20mm PVC pressure pipe and fittings then plumbed to a legal point of discharge. In some Australian States, this is allowable DIY work but check your State’s regulations.

Fitting Instructions

Q. Where are Gutter Pumpers mainly used?

A. Paved areas, decking, paths and garden beds often make fitting another downpipe difficult and expensive. A painted 20 mm PVC pressure pipe is less obtrusive in many areas than a downpipe.

Q. Is any maintenance required?

A. It is best to occasionally check for any larger debris. Debris is usually flushed past the Gutter Pumper during heavy rain before the syphonic action starts.

Q. Why can’t l fit a Gutter Pumper next to a downpipe?

A. The BCA requires inverted nozzles to be fitted at the gutter’s high point to avoid damming.

Q. Can leaves block the Gutter Pumper?

A. Gutter Pumper should be fitted near gutter’s high point as stated in our fitting instructions.
Most overflows occur near a gutter’s high point as explained at GUTTERS OVERFLOW.
Unless there is a heavy build up of debris, leaves wash from the high point during heavy rain prior to the Gutter Pumper generating a vacuum.
Gutter Pumper generates a vacuum only after water rises above the anti vortex baffle, a minimum water depth of 25mm. Prior to this, Gutter Pumper drains slowly by gravity weir flow once the water level is approximately 5 mm deep. For a small leaf to enter the outlet during weir flow, the leaf would need to do a 90 degree turn against the flow. Small leaves sucked into the Gutter Pumper during full flow are quickly dispersed.
Gutter Pumper operates with vacuum breaks whenever the water level drops below the baffle. When the vacuum stops, Gutter Pumper resumes weir flow and the water, being turbulent due to the heavy rain, swiftly flows past, flushing debris along the way.
When fitting Gutter Pumper near a roof valley or if accumulated debris is a problem, AQUATREK recommends that a suitable leaf barrier is fitted.

Q. We have a gutter that overflows about 4 - 5 metres from the downpipe. Two plumbers have said we need a bigger downpipe but one said that we should also have a rainhead fitted in the downpipe to drain the water even faster. Would fitting a Gutter Pumper be better?

A. If the existing downpipe and pop are inadequate, the water will overflow at the downpipe. Because your gutter overflows away from the downpipe, there is little chance that fitting a bigger downpipe and pop will solve the problem. Gutters overflowing near a high point are common and fitting a Gutter Pumper near the high point attacks the problem at its source.
Rainheads need to be fitted to the gutter and not in the downpipe if they are to improve the drainage. We also see larger downpipes fitted to their original pops. This does not improve drainage as drainage is determined by pop size, no matter how large the downpipe is.

Q. Our house has gutters that pool water. We understand the regulations state that gutters must slope towards the downpipes but the builder has said that the gutters were installed correctly and are compliant. What can we do?

A. Slab movement and settling can alter a gutter’s slope. The best precaution is to install gutters on new homes with more slope than the required minimum. This often requires no more than one extra downpipe.
Regardless of this, water pooling in a gutter up to a depth of 10 mm for three days is deemed acceptable!

Q. Our downpipes are fitted at the end of the walls and the gutters overflow halfway between the downpipes during heavy rain. The builder has told us the gutters are compliant but others have told us the Building Code of Australia (BCA) requires downpipes to be no more than 12 metres apart.
Is this correct?

A. The “12 metre rule” is a BCA regulation.

Prior to May 2007, the Building Code of Australia stated:
The spacing between downpipes must not be more than 12 m.

This was revised on the 1st of May, 2007 to state:
“ Downpipes - size and installation Downpipes must - (a) not serve more than 12m of gutter length for each downpipe;

When the BCA was revised on 1st May 2013, it again stated:
The spacing between downpipes must not be more than 12m.
AS/NZS 3500.3 Plumbing and drainage Part 3: Stormwater drainage & Section 5 of AS/NZS 3500.5 are  referenced in the BCA Part 2 3.5.2 as Acceptable Construction Manuals for roof drainage but the Australian Standards do not mandate a 12 metre maximum distance between downpipes.
The BCA, being the primary document, has hierarchy but the referenced Australian Standards and the BCA can be called up and mixed.
The BCA Comprises Parts 1 & 2 of the National Construction Code (NCC) and the Plumbing Code of Australia (PCA) is Part 3 of the NCC. The PCA Part D1.2 states:
“The design, construction, installation, replacement, repair, alteration and maintenance of a roof drainage system must be in accordance with—
(a) AS/NZS 3500.3; or
(b) for a Class 1 or Class 10 building—
(i) Section 5 of AS/NZS 3500.5; or
(ii) acceptable construction practice 3.1.2 and 3.5.2 of NCC Volume Two.”

HOWEVER; Most States and Territories have their own roof drainage variations written into Part D1 in their respective State clauses found in the PCA Appendix.

Part D1 does not apply in the Australian Capital Territory. Roof drainage systems are regulated under the ACT Building Act 2004.
In New South Wales roof drainage systems are regulated in:
(a) the Environmental Planning and Assessment Act 1979 and the Environmental Planning and Assessment Regulation 2000, which references the Building Code of Australia; and
(b) the Local Government Act 1993 and the Local Government (General) Regulation 2005.
Part D1 does not apply in the Northern Territory.
Part D1 does not apply in Queensland. Roof drainage is regulated under the Queensland Building Act 1975.
Part D1 does not apply in South Australia.
The design, construction, installation, replacement, repair, alteration and maintenance of a roof drainage system must in accordance with AS/NZS 3500.3 or for Class 1 and 10 buildings, comply with Section 5 of AS/NZS 3500.5 or the acceptable construction practice of Part 3.5.2 of the Building Code of Australia Volume Two.
The design, construction, installation, replacement, repair, alteration and maintenance of a roof drainage system must be in accordance with AS/NZS 3500.3 or Section 5 of AS/NZS 3500.5 as appropriate.
WA adopted the PCA on 1 MAY 2015. There are no State variations listed in the PCA.

Q. Our new home has two downpipes six metres either side of a roof valley. The gutter slots overflow during heavy rain but the builder has told us that the gutters are compliant. It is worst at the valley. The area is now concreted and fitting another downpipe would be expensive and unsightly. Would a Gutter Pumper stop the overflows?

A. Gutter Pumper would drain a lot of water but roof valleys can also attract a lot of leaves. If leaves in the valley are also a problem, fitting a Gutter Pumper and a few metres of suitable gutter mesh is invariably neater and cheaper than plumbing another downpipe.

Q. We live in QLD and our gutters always overflow. Can Gutter Pumper cope with heavy QLD downpours?

A. Gutter Pumper has been successfully tested in every Australian State, including Qld. 1 mm of rain on 1 square metre = 1 litre. When harvesting a 30 square metre roof catchment area, a Gutter Pumper can divert up to 2 mm of rainfall per minute. This is huge!

Q.  Can we use Gutter Pumper to harvest rainwater as well as stopping overflows?   

A. Yes, many people do this. Because of the shorter hydraulic head, it is best to use a 25mm X 20mm PVC reducing elbow to connect the 20 mm vertical drop to a 25 mm horizontal pipe when diverting water to the tank’s top meshed inlet. For quality rainwater harvesting, also consider connecting a Supadiverta to every downpipe.

Will my steel gutters rust if I drill holes in them?
No - and here are the reasons why they won’t.

Many types of material are used in modern gutters but by far the most common are the zinc/aluminium coated steel type. Probably 90% of the gutters now supplied are of this material and they can be either coloured or the original Zinalume finish. Below is a small table of the types of metal, the thickness required and the minimum cross sectional areas used in the gutters supplied today.

Let’s make this simple and just explain some of the terms of metal used in gutters. It would only be in very exceptional circumstances that the last four would be installed as guttering on a normal house. So now we are down to two types: ZINC Coated and ZINC/ALUMINIUM Coated – fairly simple as this is the coating over bare steel (which will rust). The diagram below shows roughly the base steel (which is the Base Metal Thickness or BMT) and the coating which is sometimes recorded as AZ or Z which simply means coated by an Aluminium/Zinc alloy or just Zinc by itself.

Most gutters supplied today are of the type covered in a Zinc/Aluminium coating over the base steel which normally would be about 0.42mm thick as in the left hand sketch above. The two coatings above are normally Zinc or Zinc/Aluminium and can be applied in three ways from as a thin layer of electroplated Zinc, a heavy layer of Zinc applied by hot-dripping (galvanized) or the technologically advanced zinc/aluminium alloy. Don’t worry too much as your gutter has a 95% chance of being of the last type of a Zinc/Aluminium alloy coated metal gutter. To explain why this is the normal practice – Zinc/Aluminium Alloy coated steel lasts up to four times longer than Zinc coated steel of the same thickness.

This Zinc/Aluminium coating serves two purposes –
   1.  By providing a physical barrier between the atmosphere and the steel
   2.  By giving a galvanic action

Painted bare steel if scratched or drilled will rust as the bare metal is exposed to the atmosphere as paint alone will not instigate a galvanic reaction. The Zinc/Aluminium coated steel if cut, scratched or drilled does not allow the steel to rust by a simple fact that the coating sacrifices itself to coat the steel from exposure to the atmosphere. So when a drill cuts a hole in the gutter, bare steel is exposed but this is quickly coated by the Zinc/Aluminium on the top and bottom surfaces through a galvanic reaction with moisture which builds up a protective Zinc coating over the exposed metal.

Galvanic reaction also protects the original downpipe drops when they are drilled or cut into the gutter. It is also exactly the same with roofing sheets that have all four edges initially exposed,  moisture provides the electrolyte that completes the galvanic reaction that soon seals up the base metal surface.

The most important aspect of roofing and gutting when considering coating is the compatibility of metals. There are many tables available that show which ones should not be used together. For example – you cannot use a Zinc/Aluminium coated roof that drains into a Galvanised (Zinc only) gutter. The colour bonded gutters are exactly the same – they have the Zinc/Aluminium coating under the paint layer and will behave exactly as the Zinc/Aluminium coated material.


Supplements downpipes during intense rain. It is not a replacement for downpipes, nor will it prevent overflows caused by blockages

Supa Gutter Pumper can prevent most overflows

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