The Importance of Distribution System Disinfection - Disinfection of Pipelines and Storage Facilities Field Guide - page 4

￿ Contact with or intrusion of foreign water during storage
and installation activities, and sometimes following
emergency repairs, most often because of premature
main shutdown and depressurization. Foreign water
includes trench water, stormwater, and other sources of
runoff. For main breaks, potable water that enters the
trench from the broken pipe and therefore contacts con-
taminated soil, is a common source of foreign water.
Distribution system storage facilities consist primarily of: ele-
vated tanks, standpipes, covered above- (or partially above-)
ground reservoirs, and underground reservoirs. The sources of
contamination for water storage facilities are similar to those for
water mains with the addition of contact or intrusion of foreign
water or matter that can occur during periodic inspections. Typi-
cal contamination routes are through missing or open vents,
hatches, doors, or roof openings.
Incorporating adequate disinfection practices for water mains
and storage facilities can reduce the risk from these potential
contamination pathways. Disinfection requirements are
described in these ANSI/AWWA standards:
AWWA Standard for Disinfecting Water Mains .
ANSI/AWWA C651. Denver, Colo.: American Water
Works Association.
AWWA Standard for Disinfection of Water-Storage
Facilities . ANSI/AWWA C652. Denver, Colo.: American
Water Works Association.
Plumbing codes address the disinfection of service lines,
valves on service lines, and customer meters. Several prominent
codes are:
International Plumbing Code , International Code
Council (formerly BOCA, ICBO, and SBCCI).
Uniform Plumbing Code , International Association of
Plumbing and Mechanical Officials (IAPMO).
National Plumbing Code , Plumbing, Heating and
Cooling Contractors Association (PHCC).