Isolation valves must be installed to facilitate new connections to the system, and to provide for the isolation of pipe segments during maintenance. Generally, 2 isolation valves per tee, and three isolation valves per cross are required. At least one isolation valve per 1,000 feet of main run must be installed. Live taps may be allowed at the PUD’s discretion.
Where tees or crosses are installed to provide for both new and future connections, isolation valves should be located to minimize loss of service when the future connection is made.