221310  Water Supply and Irrigation Systems

This U.S. industry comprises establishments primarily engaged in 
operating water treatment plants and/or operating water supply 
systems.  The water supply system may include pumping stations, 
aqueducts, and/or distribution mains. The water may be used for
drinking, irrigation, or other uses.

The data published with NAICS code 221310 are comprised of these 
parts of the following SIC industries:

    4941      Water supply
    4971      Irrigation systems