The time between the pump and the nearest faucet is usually one minute or less. A coil of plastic pipe can be used to increase contact time. The length of pipe required depends on the pipe diameter and the flow rate. For example, to achieve a 4-minute contact time with a 10 gallon per minute flow rate, you would need 128 feet of 3 inch nominal diameter pipe or 480 feet of 1.5 inch nominal diameter pipe. Your pipe supplier should be able to assist you in selecting the proper size and length for your required contact time and flow rate.
Continuous chlorination is expensive and requires frequent and intelligent management.
It should not be considered for disease-causing bacteria control until other alternatives have been fully explored. Chlorination is not a substitute for a safe pure water supply and should be used only when other options have been thoroughly investigated. For further information contact your local county extension office or state health department. AE-1046, June 1992 NDSU Extension Service, North Dakota State University of Agriculture and Applied Science, and U.S. Department of Agriculture cooperating. Sharon D. Anderson, Director, Fargo, North Dakota.