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22 Chapter 1 Introduction to Water Systems

Service or
Street curb box Foundation wall
Supply to
Frost building
depth
Corporation Stop and waste cock
cock or stop
Caulked
Goose neck Check
pipe
Union Union valve Drip
sleeve
valve
Curb cock Valve Meter Testing Valve
Street Service pipe or stop tee
main Hose end
Basement floor

Figure 1.10 Service Pipe, Fittings, and Accessories. There are many possible modifications, both
inside and outside the building. In many instances, the meter is conveniently placed in a vault outside
the building.

1.9.4 Capacity
The capacity of distribution systems is dictated by domestic, industrial, and other normal
water uses and by the standby or ready-to-serve requirements for firefighting. Pipes should
be able to carry the maximum coincident draft at velocities that do not produce high pres-
sure drops and water hammer. Velocities of 2 to 4 ft/s (0.60 to 1.2 m/s) and minimum pipe
diameters of 6 in. (150 mm) are common in North American municipalities.

1.9.5 Service to Premises
Water reaches individual premises from the street main through one or more service pipes tap-
ping the distribution system. The building supply between the public main and the take-offs to
the various plumbing fixtures or other points of water use is illustrated in Fig. 1.10. Small
services are made of cement-lined iron or steel, brass of varying copper content, admiralty
metal, copper, and plastics such as polyethylene (PE), high density polyethylene (HDPE), or
polyvinyl chloride (PVC). Because lead and lead-lined pipes may corrode and release lead to
the water, they are no longer installed afresh. For large services, coated or lined cast-iron
pipe (CIP) is often employed. For dwellings and similar buildings, the minimum desirable size
of service is ⁄4 in. (19 mm). Pipe-tapping machines connect services to the main without
3
shutting off the water. They also make larger connections within water distribution systems.

1.10 WATER SYSTEMS MANAGEMENT
Construction of water supplies from the ground up, or their improvement and extension,
progresses from preliminary investigations or planning through financing, design, and con-
struction to operation, maintenance, and repair. Political and financial procedures are in-
volved as well as engineering.

1.10.1 Municipal Supplies
The cost of public water supplies in the United States provides the reader with some concept
of the magnitude of engineering activity and responsibility associated with their design
and construction. Per capita investment in physical plant depends on many factors: nature,