Abstract
The interruption of supply in water distribution systems is a common management practice particularly prevalent in developing countries. Upon reopening, the air is expelled through user service pipes, which causes over-reading and seriously impacts the water meter reliability. This paper aims to assess by laboratory tests the effects of air flow on water meter performance by laboratory tests, using a set-up with diameters comparable to those of real water systems. The improvements introduced by applying unmeasured-flow reducer and air valves at different locations are also tested. The relevance of the results of the laboratory activity for practical applications is discussed, both for reducing the over-reading and improving the reliability of the water meters.