Greywater and Rainwater- Perth and Fremantle - Australia - Water Capture - Mark Harland


Tanks: Poly tanks, round or slimline ranging in size from 250 litres up to 32 000 litres. A range of colourbond colours for the poly tanks. Corrugated tanks with aquaplate liners in zinculume, paperbark cream or eucalypt green. Again in round or slimline and built to the size you want. Underground rainwater tanks made from heavy duty polyethylene are buried underneath your garden or driveway. Steel tanks with rubber liners that go up to 250 000 litres. Alternatively you may already have your own tank or a tank in mind that needs to be connected.

Filtration: Rainwater falling on the house roof may airborne contaminants from industries polluting the sky. House roofs may have lead flashings, asbestos, ash from wood heaters, bird droppings and overhanging trees dropping leaves, nuts and pollen. All house roofs will collect sand and dust over time. Depending on where your collected rainwater goes to will depend on the level of filtration required.

If the rainwater is being used solely for the garden a leaf eater and a screen mesh filter on the pump may be all that is required.
When the house is subject to roof contaminants we may recommend good quality gutter guard mesh, leaf eaters, first flush devices, a combination of mesh, cartridge and carbon filters of varying micron. Uv filtration and ozone injection are alternatives for killing bacteria and living organisms.

Pumps: A range of pumps can be used to transfer rainwater depending on the application. A common water pump nowadays, for household usage, are submersible pumps. Being situated inside the tank they are safe from vandalism, quieter, cannot overheat and are out of site. Depending on what the rainwater line feeds will determine what size pump is required. Simple garden applications will only require a surface mounted pump. Whole of home connections will require a pump that can handle multiple open outlets with sufficient pressure.

Switching Devices and Pressure Controllers: Switching devices automatically detect whether you have rainwater available in your tank and tell the rainwater pump to come on when a tap is opened in the house. If no rainwater is available scheme water is sent to the house. The beauty of ‘Switching Devices’ is that they automatically detect what water source to provide the home with, they have inbuilt backflow prevention, the pump only runs when rainwater is being used and if there is a power failure mains water will still flow to the house.

Pressure Control Switches detect a drop in pressure (ie when a tap is opened) and send a signal to turn the pump on. These devices are suitable when there is only one source of water available.

Maintenance: Some basic maintenance is required to keep your rainwater clean and pumps/ controllers functioning correctly. Gutters need to be kept clean. Leaves and nuts that fall in the gutter will break down over time and release tannins that end up in the rainwater. Screen filters will not take out this discolourment of the rain water and you will get a yellow/ brownish rainwater in your house. Good quality gutter mesh will stop the majority of tannins entering the tank. Screen filters, leaf eaters, first flushes will all need to be periodically cleaned depending on your set-up.

Some people suggest that tanks need to be de-sludged every 2-3 years, another thought is that the film that grows around the inside and base of the tank is similar to a bio-filter where good micro-organisms live in balance with their surroundings and may in fact kill any bad micro-organisms. If organic matter and sand/silt can be kept out of the tank it is unlikely that tanks will need to be cleaned out very often at all.





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