How do I disinfect the water?
There are a range of options available which include UV irradiation, boiling and disinfection with chlorine. For domestic premises, boiling or disinfection are the two most common methods adopted.
Boiling water will kill pathogens (kettles with an automatic shut off are suitable for this purpose). Once boiled, the water can be cooled and stored prior to use.
To achieve effective disinfection, it is necessary to add sufficient chlorine to provide a free chlorine residual of >0.5mg/l (after a contact time of 30minutes). This can be measured using a swimming pool test kit. As a general rule, to achieve the >0.5mg/l free chlorine residual, add 40ml of liquid sodium hypochlorite (12.5% available chlorine) per 1000ml of water or 7g of granular calcium hypochlorite (75% available chlorine) per 1000ml.
Both sodium and calcium hypochlorite can be purchased from local pool suppliers, supermarkets and hardware stores.
How do I determine the size of my tank?
To calculate the volume of a rectangular tank, use the following formula:
Volume (in litres) = depth (cm) x width (cm) x length (cm) divided by 1000
If your tank is a cylinder you will need to know the Height and the Radius to calculate the volume using the formula V = πr2h where 1 cubic metre will equal 1000 litres.
Water Quality Testing
Regular microbial quality testing is not normally required for a domestic premises and generally would only be undertaken as part of an illness investigation. If microbial analysis is to be undertaken, a sterile100ml plastic or glass container can be used. The sample must be stored between 1 – 4C and analysis undertaken within 24 hours.