Page 83 - Water Loss Control

Validation of Sour ce Meter Accuracy 65

Volume,
Component million gal
1 Volume from own sources (treated water) 3480.76
2 Adjustment: source meter error +136.89
3 Adjustment: changes in reservoir and tank +0.83
storages (±)
4 Other adjustments (specify) 0
5 Total adjustments = lines 2+3+4 +137.72
6 Volume from own sources (adjusted) = Lines 3618.48
1 ±5
7 Volume of water imported (adjusted) 783.68
8 System input volume = volume from own 4402.16
sources + water imported
9 Volume of water exported (adjusted) 0
10 Water supplied = system input volume – water exported 4402.16

TABLE 6.3 Water Balance Calculations to Determine the Value of Water Supplied for County
Water Company
Table 6.3 shows data for County Water Company and a series of tabulations that the
water auditor should follow to arrive at the proper value of water supplied for a retail
water distribution system. The procedure to obtain the data included in Table 6.3 is
discussed below.

Compile the Volume of Water from Own Sources
Identify all water sources that are owned or managed by the water utility to supply
water into the distribution system. Such sources can include raw water that is treated
adjacent to sources such as wells, rivers, streams, lakes, reservoirs, or aqueduct turnouts.
However, most water audits are performed on the potable water distribution system so
that the “source” is often the location where treated water enters the distribution system;
which is often the effluent of the water treatment plant. All volumes from such sources
should be metered, with routine meter testing and upkeep conducted so that volumes of
water taken from the sources are registered accurately. Data should be available on a
daily, weekly, or monthly basis to compile into an annual volume of water supplied from
each source. Meter information can be kept in a table similar to Table 6.4.
In this example, County Water Company withdraws water from three sources: an
aqueduct, a well field, and an interconnection (city intertie) with a neighboring water
utility. Table 6.5 is a summary of water withdrawn from these sources for the year of
2006, illustrating how source meter and flow data can be arranged and adjusted for the
water audit period. The data listed is based upon uncorrected meter registrations. In
this example, water withdrawn from the aqueduct and well field is presumed to be
untreated water. For the simplicity’s sake, it is assumed that the volumes of water for
these two sources shown in Table 6.5 are the same volumes delivered to the water dis-
tribution system after the water undergoes treatment. This simplistic assumption often