Rainwater tanks provide a valuable supply of water, which can be used for a wide range of purposes in the home, including drinking, washing, laundry, toilet flushing & gardening. Providing that the system is well maintained, rainwater is considered a safe drinking supply.
A sensible maintenance program for the catchment area & rainwater tank will reduce the amount of unwanted matter from entering the water supply. Regular cleaning of the gutters will remove bird & animal droppings, leaves & dust, while the occasional draining & cleaning of the tank will reduce sediment build up & any organic loading.
If you are concerned about the smell, colour or presence of organic material, we suggest the following options:
Boiling - Small quantities of water required for drinking purposes can be boiled vigorously for one minute to kill any harmful bacteria. To improve the taste of boiled water, pour it back and forth from one container to another, or let it stand for a few hours before consumption.
Chlorination - Water contaminated with harmful bacteria can be disinfected using chlorine. Routine chlorination is generally unnecessary & may increase corrosion in galvanised steel tanks. As a general rule the addition of liquid sodium hypochlorite (12.5% available chlorine) per 1000 litres of water or 7 grams of granular calcium hypochlorite (75% available chlorine) per 1000 litres of water will give a reasonable assurance of effective disinfection. Ideally water should not be used for 24 hours after chlorination.
If in any doubt empty (use the water on the garden), clean & refill the tank.
Please note that it is recommended that if you have a general concern about the quality of your rainwater it is better to ensure proper maintenance of your rainwater tank & catchment than have your water tested.
Should you choose to proceed with water testing, the Australian Water Quality Centre (AWQC) offers two groups of tests - microbiological & chemical. Contact the AWQC on 1300 653 366 to organise having an application form sent out to your address.
Australian Drinking Water Guidelines - follow the links to download full text, chapters, & fact sheets
Guidance on the use of rainwater tanks - information document
Where it is necessary for bore water to be used and human consumption or contact is likely, the water should be tested by specialist laboratories prior to use. Bore water can contain a number of biological & chemical contaminants.
Contaminants can occur naturally in the ground, although some contamination sources can be prevented, in the following ways: