To obtain a member for city water supply works using a copper alloy the mechanical properties such as machinability, castability, hot-water flowability and pressure-resistance of which are kept in the same level as the conventional lead-used copper alloy while the content of lead is suppressed in minute amounts.

The copper alloy, in which 2.0-5.9 wt.% tin, 1.5-3.0 wt.% nickel, 5.0-12.1 wt.% zinc, 0.5-1.1 wt.% bismuth, 0.009-0.15 wt.% phosphorus and lower than the detecting limit of selenium content and 0.01 wt.% silicon content and the balance copper with the other impurities, is manufactured.