Water – Private Drinking Water

Water quality testing

Water quality testing assists in determining whether any contaminants are present and that the drinking water supply meets health-based drinking guideline values.

Routine water quality testing is required to be assured that water is safe to drink. This chapter details the different types of routine water testing required to determine whether a private drinking water supply is safe.

Microbe testing

Microbe testing means testing the microbiological quality of the water for detecting the presence of pathogens such as Escherichia coli (E. coli), which may indicate faecal contamination and the possible presence of disease-causing microorganisms.

The recommended testing frequency for microbe quality is monthly.

Microbe testing must be conducted by a National Association of Testing Authorities (NATA) approved laboratory. Accredited facilities can be found on the NATA website.

Chemical testing

Chemical testing is a comprehensive analysis that is undertaken to determine the chemical and physical quality of a water supply, and to identify any unusual contaminants.

The recommended testing frequency for chemical and physical quality is annually.

Chemical testing must be conducted by a NATA approved laboratory. Accredited facilities can be found on the NATA website.

Private drinking water must meet the health guidelines outlined in the Australian Drinking Water Guidelines by testing the following chemical and physical characteristics: antimony, arsenic, cadmium, chromium, copper, fluoride, lead, nickel, nitrate, manganese, sulphate, pH, total dissolved solids, total hardness, and turbidity.

NATA

Water samples can be collected by schools and couriered to a NATA lab for microbe testing. The lab will provide information on water sample collection requirements for microbe testing and chemical testing.

The NATA website can be used to locate your nearest lab by searching for your closest regional city. An alternative is to use a search engine to locate a NATA lab. Refer to the NATA quick reference guide (available on the Resources tab) for further information on locating your nearest lab on the NATA website.

NATA can be contacted on 1800 621 666 for assistance in finding your closest lab. If there are no nearby NATA laboratories, samples can be mailed overnight instead via express shipping. For instructions on how to collect and post samples, please contact your NATA lab of choice.

Treatment testing

Treated water, such as chlorinated water, must be tested to ensure it remains within the acceptable pH ranges.

The pH of the water must be 6.5 to 8.5. A pH of greater than 8 can decrease the efficiency of chlorine disinfection.

The recommended testing frequency is weekly.

Treatment testing can be undertaken by the nominated school person responsible for the private drinking water supply using standard pH strips. These pH test strips can be found in standard swimming pool water test kits.

Ad hoc water quality testing

Other events which require laboratory water quality testing (microbe and chemical testing) include:

• before using the water from a new treatment system
• after a treatment system has been altered
• following any infrastructure works that may affect the catchment area (roof gutter repairs)
• after a significant event such as fire, flood or chemical spill that may have affected the water quality
• after prolonged periods of shutdown, such as school holidays.

Water treatments

Treating the water supply helps to ensure the health of consumers is not placed at risk. The most common treatment methods include filtration and disinfection with ultraviolet (UV) light and/or chlorine.

To select the best method to treat the school’s water, consult a water treatment specialist.

Filtration

Filters are used to remove sediment and are commonly installed with your regular plumbing between the roof catchment area and the storage tank. They are normally used in combination with UV light and/or chlorine disinfection.

Disinfection

Disinfection is typically the last step of water treatment before being distributed for drinking use and generally includes UV and/or chlorine disinfections.

UV disinfection

UV disinfection uses UV light that disinfects water by emitting a light that will enter and damage a microorganism’s cellular function so that it will not be able to grow. UV light is not a filter so microorganisms and suspended matter will not be removed from the treated water.

UV disinfection systems need to be designed and installed by a water treatment professional. Typically UV disinfection requires less maintenance and ongoing upkeep compared to chlorination.

Chlorination disinfection

Chlorine is a chemical additive often used to treat small drinking water supplies because it is easily accessible, cheap and can treat large volumes of water. Water can be chlorinated through an automatic dosing system or manually added to the storage tank. The effectiveness of chlorine can be short-lived and will only treat water in the tank at the time of dosing; fresh run-off into the tank may not be disinfected. Schools are encouraged to undertake weekly pH testing of water treated with chlorine.