Many concerns result from information on new waterborne agents, treatment problems of raw water qualities, biofilm development in some distribution systems, and special quality needs unique to hospitals and industries. Protozoan cyst penetration after some disinfection practices involving surface water impoundments and virus occurrence in poorly protected groundwaters justify expanding minimum surface water treatments and the required disinfection of groundwaters unless a demonstrative data base supports exceptions. Official monitoring of small supplies must be increased and a rapid alert established to inform plant operators of unsatisfactory qualities. Optional tests to analyze water quality should be encouraged to allow prompt adjustments and corrections and to supplement official monitoring. Improved supply to hospitals and food industries is possible by systematic flushing of plumbing networks and associated devices. Disinfection or point-of-use devices may meet the water quality requirements of special applications but need careful monitoring and maintenance to prevent water quality reversals.