Water quality and drought

Water is a precious resource, and this is never more apparent than in a time of drought.

Drought is a natural feature of our climate, something we have learnt to live with. Although the multi-barrier approach to water quality developed by Sydney Water and the Sydney Catchment Authority is world class, drought can have an effect on the quality of the drinking water supply.

Currently Sydney, Illawarra and the Blue Mountains are experiencing drought conditions. The Bureau of Meteorology provides daily and long term weather forecasts.

To help extend our water supplies during this drought, mandatory water restrictions are now in place. The Sydney Catchment Authority advises that three to four days of heavy rainfall is needed in catchment areas to return dam levels to an average 70 per cent of their full capacity. When this happens, Sydney Water and the Sydney Catchment Authority may recommend that water restrictions be lifted.

Sydney Water will inform customers when restrictions are lifted. However, the lessons learnt during the drought should not be forgotten. It is important that we all continue to conserve water all year round, rain or shine.

Drought, bushfires and heavy rain after a drought have the potential to affect the quality of raw water in our dams in varying ways, both positive and negative. Fortunately, Sydney's water treatment facilities and monitoring systems are world class and are continually being improved to cope with these challenges.

During drought and after bushfires, vegetation in catchment areas is sparse. This vegetation is one of the natural barriers which help prevent impurities from entering water supply dams.

Drought-breaking rain is a very welcome event. However, particularly heavy rainfall in the catchment areas can cause sudden run-off into the dams. With sparse vegetation reducing the natural filtering ability of the catchments, this rainfall can wash higher than normal levels of sediment, organic material, ash and micro-organisms into the dams. Some of these conditions preceded the 1998 water contamination incident.

To counter this, Sydney Water and the Sydney Catchment Authority have a multi-barrier approach to protecting water quality. This includes catchment protection, storage management, water filtration and a fully enclosed distribution system to consumer taps. The system now provides one of the most closely monitored and consistently high quality drinking water supplies in the world. Water quality testing takes place at every stage in the system.

The latest water quality information on pathogens (organisms capable of producing disease) is provided six days a week on the Sydney Water website. Visit the website to access the daily and quarterly reports.

NSW Health examines Sydney Water's water quality and compliance with the Annual Drinking Water Quality Monitoring Plan. In the unlikely event that there are concerns about drinking water quality, Sydney Water and NSW Health have protocols in place to issue clear public advice on drinking water quality.