By international standards SA Water has one of the lowest water loss rates in the world (7%) and one of the very best in Australia. (Water authorities in Great Britain lose between 25 and 30%.)

 

While by industry standards this is regarded as excellent, SA Water and United Water are constantly striving to improve this figure.

 

SA Water is constantly testing and inspecting mains systems and if a system shows increasing problems/leakage the system is repaired. (eg; Coffin Bay’s mains system showed increasing water loss due to corrosion of fittings as a result the whole system was upgraded in 2002.)

 

Loss is due to accidental mains damage (eg; during road works), legitimate un-metered use (eg; water used by MFS/CFS to fight fires), seepage from the many millions of underground mains joints, burst mains and necessary water drainage for maintenance and repairs.

 

Adelaide’s reactive soils are the principal cause of much of the leakage and burst mains (this can be compared to the damage and cracking homes and buildings in Adelaide suffer from the constantly shifting soils – the same principle applies.) Movement in the soil pulls joints apart and in extreme cases can crack mains.

 

While the age of some mains can be an issue, 84% of the mains have been laid since the 1950s. (Some mains laid in 1873 continue to perform well while bursts have been reported in mains laid in the 1960s and 70s.) Mains are made of cement, iron, plastic and composites (eg: asbestos-cement, concrete-lined iron.)

 

The value of Adelaide’s 8,600 kilometre mains water system is estimated at $1.3 billion – to replace only those mains laid before 1950 would cost an estimated $250 million.

 

If Adelaide’s entire mains water system was replaced there would be leaks and cracks appearing in the new mains within weeks due to the nature of the soil.

 

United Water repair approximately 2000 leaks and burst mains every year (this figure remains pretty constant.)

 

Evaporation: All water sources are subject to evaporation (even rainwater tanks). It is natural. Adelaide’s catchments are estimated to lose 7 – 8% each year to evaporation.

 

Covering reservoirs has been suggested as a solution. In fact this would barely halve the evaporation rate and could negatively impact on the reservoirs’ ecosystems. To cover Adelaide’s main reservoirs would cost an estimated $200 million.