Rehabilitation of Wastewater Collection and Water Distribution ...

Table 4. Water Distribution Systems by Material (AWWA, 2004)
Material Miles Installed
% of
Total
Asbestos Cement 136 196 15.8
Cast Iron unlined 153 415 17.8
Cast Iron cement mortar lined 159 824 18.5
Cast Iron 28 476 3.3
Concrete Prestressed 23 584 2.7
Ductile Iron unlined 35 916 4.2
Ductile Iron cement mortar lined 150 705 17.5
Ductile Iron other lining/lining not known 2 494 0.3
GRP 665 0.08
PE 3 349 0.4
PVC 114 152 13.2
Steel 34 047 3.9
Other/Not known 20 169 2.3
Total 863 000 100
Table 5. Water Distribution Systems by
Diameter (AWWA, 2004)
Diameter Range,
% of
inches Miles Installed Total
48 6 600 0.8
Total 863 000 100
Table 6. Water Distribution Systems by Age
(AWWA, 2004)
Age,
years
Miles
installed
% of
Total
0 to 10 245 000 28.4
10 to 25 325 500 37.6
25 to 50 156 500 18.1
>50 137 000 15.9
Total 863 000 100
Up to the 1940s, water mains were chiefly unlined cast iron and steel. Cast iron (CI) pipe eventually gave
way to ductile iron (DI) pipe and ceased being used altogether in the mid 1980s. Today, 56 percent of all
underground water mains are CI pipe. The primary problem with unlined CI pipe is both internal and
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