Online Reporter
Remember Deketeke
Municipal Correspondent
The City of Harare has clarified that air trapped in water pipelines can cause both prepaid and conventional meters to register apparent consumption, following concerns from residents over water charges.
In a statement on Tuesday, the council, in partnership with Helcraw Water, said prepaid meters operate on the same mechanical measurement principle as conventional meters, with the main difference being the payment platform.
“Both prepaid and conventional meters contain a precision-engineered impeller that rotates in response to fluid passing through the meter to measure consumption,” said the council.
However, under abnormal hydraulic conditions, compressed air moving through the distribution network can cause the impeller to rotate.
“This phenomenon is associated with the presence of entrapped or pressurised air within the pipeline system, rather than with a defect in the prepaid meter itself,” the council said.
Air can enter water mains following pipe bursts, emergency repairs, pipe replacement and intermittent water supplies.
“When the water supply is restored, the compressed air is conveyed through the distribution network and may pass through customer meters before normal water flow resumes,” the statement said.
Council said it was installing combination air valves and pressure relief/air release valves at strategic points to reduce the problem.
Residents were urged to close taps when only air was being discharged and report the incidents promptly to council or Helcraw Water.
“This will help minimise unnecessary meter rotation and improve overall system performance,” council said.
