Section 604.1420  Valves

a)         A sufficient number of valves must be provided to isolate portions of the distribution system during repairs and maintenance and to facilitate unidirectional flushing.

b)         Location.  Unless otherwise approved by the Agency under Section 604.145(b), valves must be located:

1)         at not more than 500-foot intervals in commercial districts;

2)         at not more than two blocks or 1200-foot intervals in other districts.