losses and wastage

WATER LOSSES AND WASTAGE

Water loss is referred to as non-revenue water. This means that water is produced in a network but never reaches the consumer. This may be due to ageing networks, metering inaccuracies, theft or unmetered consumption like water used from fire hydrants. Other causes of loss could be due to leakage in mains due to 

• Corrosion
• Cracks
• Faulty joints
• Fixtures in consumer premises (faulty washers, valves and taps)

Leakages could be

• Background leakage
• Unreported leakage or
• Reported leakage

Leakage could lead to consumer inconvenience, damage to infrastructure and increased loading on sewers due to infiltration, excessive cost due to damage to infrastructure and excessive production costs. It may also damage meters and lead to errors in water bills. Leakage could also lead to health risks due to infiltration of sewage other pollutants into the pipe network.

• Water loss can be termed in two categories
• Physical losses (Technical or real losses)
• Non-physical losses (Non-technical losses / Commercial or apparent losses)

Physical losses mainly occur due to leakage of water in the network and comprise of physical losses from pipes, joints & fittings, reservoirs and overflow of reservoirs and sumps.

Non physical losses include

• theft of water through illegal, already disconnected connections, 
• under-billing either deliberately or through defective meters, 
• water wasted by consumersthrough open or leaky taps,
• errors in estimating flat rates and
•  public stand posts and hydrants

Leakage detection methods

• Visual inspection
• Sounding rods
• Electronic leak detectors
• Using radio isotopes
• Plotting hydraulic gradient line

Water wastage can be reduced by

• Usage of dual flush water closet cisterns
• Spray taps reduce wastage by reducing flow of water from taps
• Using flow limiting valves to set the amount of water flowing through the pipe
• Water collection systems can save large volumes of water by collecting water that would otherwise be lost
• Construction of rain water harvesting systems
• Recycling grey water