Smokey Rainwater?

Published on 14 January 2020

With huge areas of Australia blanketed by smoke from the continuing bushfires, home owners many kilometres from the fires are experiencing, in some part, one of the consequences of the fires - smoke tainted rainwater.

While all rainwater tanks on homes should be installed with first flush diverters, even these devices can’t stop the smoke from infiltrating the water already in tanks.

Some particulate matter washed into the rainwater tanks can be removed by using cartridge filters. Particulate removal can be achieved by using a two-stage process.  First remove the larger particles with a 20 micron pleated filter cartridge. Secondly, follow with a 1 micron depth cartridge such as a polyspun filter cartridge.

While particulate matter in the smoke is part of the problem, the major component affecting the taste and odour is chemical in nature, and thus it is impractical to remove using normal domestic filters.

The most practical approach for taste and odour removal from home rainwater tanks is to pass the water slowly through a carbon cartridge. These cartridges are sometimes mistakenly referred to as filters, but they perform a different function to a filter. They fit into the same housings as the filter cartridges

Carbon cartridges rely on chemical absorption to lock up the dissolved gases and impurities thus removing them from the water. To do this they rely on exposure time to allow the carbon to do its job.

“One of the most common errors when using carbon cartridges” says Maris Romans, Davey Water Products’ Product Manager for Water Treatment “is consumers trying to allow high flow rates through their carbon cartridge. The longer the exposure time the better the absorption of the chemicals will be”.

A good quality carbon block cartridge to suit a 10” large diameter or “Jumbo” cartridge housing is best suit to supply one tap at a time. A longer 20” large diameter cartridge is sufficient for two outlets at once.

Neither filters nor a carbon cartridge will sanitise the water, so if live organisms or pathogens in the water are a concern other methods of treatment are available.

Davey Water Products offer a range of water filtration, sanitisation and purification products ideal for rainwater tanks. These products are available Australia wide via your local Davey reseller. Find your local Davey reseller today.

For water tanks directly affected by fire retardants see the links below from the various state government websites. You may need to replace your water as it may not be safe for human or animal consumption.