Page 80 - Water Loss Control

62 Cha pte r S i x

utility managers and regulators should give high
priority to the use of accurate metering at all sources.
All water sources should
All water sources should include flowmeters that
include flowmeters that are are technologically current, accurate, reliable, well
technologically current, accu- maintained and—ideally—continuously monitored
rate, reliable, well maintained by a Supervisory Control and Data Acquisition
and—ideally—continuously (SCADA) System or similar monitoring system.
monitored by a Supervisory The water supplied value is a summation of sev-
Control and Data Acquisition eral registered water volumes that are routinely
(SCADA) System or similar measured via source meters. This value is calculated
as a composite value that includes as components
monitoring system.
the primary untreated and/or treated water meters,
meters registering water going into and out of tanks,
basins, and reservoirs, and meters measuring water across pressure zones or district
metered areas (DMAs). Three requirements are necessary to ensure that the value of
water supplied is well validated:
• Appropriate meters should be installed at the key metering locations in the
supply infrastructure so that water volumes can be reliably registered.
• Source meters must be well maintained and calibrated to ensure that they
produce an accurate measure of the volume registered.
• Source meter data should be reliable and accurately archived—preferably on a
continuous, real-time basis—with flows into and
out of all pressure zones or DMA and storage
facilities properly summed and balanced to achieve
The water supplied value is an accurate volume of water entering the distribution
calculated as a composite value system on a daily basis.
that includes as components
In conducting the water audit, the auditor
the primary untreated and/or
should assess the adequacy that these requirements
treated water meters, meters
are met and launch work to correct any deficiencies.
registering water going into and
Work to install, test, calibrate, repair, or replace
out of tanks, basins and reser- source meters should be identified as part of the ini-
voirs, and meters measuring tial top-down development of the water audit. This
water across pressure zones or may be particularly necessary if key metering loca-
district metered areas. tions lack working meters and/or metered data is
believed to be in serious error.

6.2 Key Source Meter Sites for Proper Flow Balancing
Water audits are most commonly conducted to track treated drinking water in transit
through retail distribution systems. Separate water audits can also be conducted on
wholesale transmission systems carrying untreated (raw) water or treated water; or
discrete pressure zones or DMAs inside of a retail distribution system. Table 6.1 lists
system configuration locations where metering is typically employed. In this publica-
tion, the water audit process is discussed in terms of the retail distribution system and
the metering sites given below are those encountered in a typical retail distribution
network. Figure 6.1 illustrates a basic retail distribution system configuration for the