SOURCE AND QUALITY OF RAW WATER	PRINCIPLES USED IN TREATMENT
VIRGIN SURFACE WATERS	DISINFECTION
SURFACE WATERS OF GOOD QUALTIY	COAGULATION SEDIMENTATION RAPID SAND FILTRATION DISINFECTION pH ADJUSTMENT
SURFACE WATERS OF POOR QUALITY	AERATION COAGULATION SEDIMENTATION RAPID/SLOW SAND FILTRATION DISINFECTION pH CORRECTION
GROUND WATERS OF PROVEN SAFETY	NO TREATMENT
GROUND WATERS SUBJECT TO SLIGHT POLLUTION	DISINFECTION
HARD WATERS ­ GROUND OR SURFACE	SOFTENING SEDIMENTATION
	FILTRATION DISINFECTION