Sydney
19.20 Other urban water system decreases

The volume calculated for this line item includes losses attributed to pipe bursts and non-revenue potable water calculated by Wingecarribee Shire Council and  Shoalhaven City Council.

A leakage value is derived by a calculation of the total water treated less authorised potable supply (line item 19.4). The New South Wales Office of Water will make adjustments if the calculation produces a figure that is outside a specified percentage of total water supplied.

Estimated uncertainty, based on meter accuracy and professional judgment on determination of boundaries of water supply areas beyond the Sydney region, is +/– 5%.

The value represents the total volume of leakage and losses from the potable water supply system. The volume is based on the water balance method, where potable water production figures from the water treatment plants are configured with the consumption figures obtained by flow meter readings at listed properties.

• Data represents total leakage and loss from potable and nonpotable water supply systems, as the breakdown between the two supplies is not available.
• Total volume of leakage is based on an estimated 11% loss from the system.

The volume is based on measured data. Estimated uncertainty based on meter accuracy, professional judgment and organisational practice is +/– 20%.