Southwest Sydney drinking water runs low

Southwest Sydney residents are being urged to turn off washing machines and avoid watering their gardens as drinking water supplies run low.

Heavy rain in recent days has put "enormous pressure" on the Macarthur Filtration Plant, leaving high levels of leaves, dirt and other organic matter in the water catchment, the state government says.

This has made it difficult for the plant to operate, leaving less drinking water in local reservoirs than usual.

Sydney Water on Tuesday called on people in Campbelltown, Narellan, Prestons, Macarthur and Camden to conserve water while the debris is cleared out of the filtration plant.

Residents in those suburbs have been asked to hold off non-essential water use.

Sydney Water says despite the low levels of drinking water in those areas, the water is safe to drink.