connections, as it is accurate for very low flow. A flow
above normal causes rapid wear. The disk type of
meter contains a measuring chamber of definite
content in which a disk is actuated by the passage of
water. Each cycle of motion of the disk marks the
discharge of the contents of the measuring chamber.
By means of gearing, the motion of the disk is
translated into units of water volume on the register
When installing a water meter, make sure it is
horizontal and that it operates under back pressure.
The meter should be located near the pressure-
reducing valve at underground level; so in freezing
temperatures, ensure the meter is protected from
Water is measured in terms of rate-of-flow
(volume passing in a unit of time) or total volume.
Units and equivalents usually are as follows:
Cubic feet per second (cfs)
46,315 gallons per
Million gallons per day (mgd)
NOTE: IN READING A METER, YOU
SHOULD FIRST DETERMINE WHETHER IT IS
MEASURING THE WATER FLOW IN CUBIC
FEET OR IN GALLONS.
Two general types of meter dials are used: the
straight-reading type and the circular-reading type.
Each type is discussed in the following paragraphs.
The STRAIGHT-READING DIAL shown in
figure 4-17 may be read in the same way as mileage on
an automobile. When the meter register has one or
more fixed zeros, always be sure to read them in
addition to the other numerals.
In the CIRCULAR-READING DIAL, when the
hand on a scale is between two numbers, the lower
number is read. If the hand seems exactly on the
number, check the hand on the next lower scale. If that
hand is on the 1 side of zero, read the number on
Figure 4-17.Straight-reading meter dial.
which the hand lies; otherwise, read the next lower
number. The procedure for reading the circular-
reading dial, shown in gallons in figure 4-18, is to
begin with the 1,000,000 circle and read clockwise
to the 10 circle, the scales registering 9, 6, 8, 7, 2, and
1; respectively, making a total of 968,721 gallons.
Figure 4-18.Reading the circular-reading meter dial in