Disinfecting Potable Water Lines
ater mains and plumbing that carry potable water must be free of bacte- rial contamination to protect the health of people using the water. Bacteria capable of contaminating potable water can get into water mains and pipes through several ways: W
during manufacture or storage of pipes used in the water system
during construction of the water system
during routine or emergency repairs of damaged pipes already in service
from contaminated water or particulates entering the system from the water
source or other parts of the water system
An effective way to reduce problems with bacteria in water systems is to prevent contamination of the pipes during storage, construction, and repair.
Storing Pipes and Fittings. During storage or before being installed, large- diameter pipes, such as those commonly used for water mains, make ideal habitat and nesting sites for rodents and other animals. Nest materials, feces, and urine left inside the pipes by these animals will support bacterial growth. Storing pipes prop- erly before use and while awaiting installation at the construction site greatly reduces these types of contamination problems. Avoiding prolonged on-site storage of pipes and fittings during construction by scheduling the delivery of construction materials to coincide closely with the installation time reduces chances of contamination.
You must clean and disinfect the pipes before installation. Cleaning involves removing all dirt and particulates on the inside surfaces of the pipes. Once thoroughly cleaned, swab interior surfaces with a chlorine solution to kill any bacteria that could be growing there.
Installing Water Lines. Follow the American Waterworks Association (AWWA) and state and local guidelines when installing water mains and plumbing. This re- quires keeping pipes, fittings, valves, and other components of the system clean and dry during installation. If you install pipes underground, suspend or elevate them dur- ing the coupling process to prevent contact with soil or water in the trench. Use only approved sealing methods and materials when constructing the system to prevent the introduction of toxic materials or bacteria. Seal all pipe openings with watertight plugs when work on the installation stops for the day or for any significant period.
Flush particulates such as dirt, leaves, and other debris out of the system be- fore putting it into use. This eliminates the possibility for these materials to support bacterial growth.
DISINFECTING POTABLE WATER LINES