The following advice from the Department of Health and Human Services relates to the recent dust storm impact on rainwater tanks and is likely to be of interest to those reliant upon roof catchment for their rainwater tanks:
Dust-storm affected rainwater supplies
High winds have swept the dry topsoil into the air across South Australia, New South Wales and Victoria.
If your rainwater looks, smells or tastes unusual, as a precaution, use bottled water for drinking and food preparation until your rainwater returns to normal.
Dust affected rainwater may stain light coloured laundry.
If you suspect your roof is still covered in dust or if dust storms are forecast, disconnect downpipes to prevent additional dust entering your tank and reconnect after a good flush of rain (NB. Have a reminder in place to reconnect downpipes following a rain event).
Over time, the dust will settle in the bottom of your tank. Once the dust has settled, contact a professional tank cleaner to remove the dust by de-sludging your tank. (To regularly maintain your rainwater tank, desludging is recommended to occur every 2 years).
Filtration may not necessarily remove fine particulate dust from the recent dust storm. Some members of the public have reported that the fine particulate dust is passing through their existing filtration system. Talk to a water treatment specialist or the supplier of your filtration system for specific advice on the treatment of your water supply.