The District's water supply during the winter months is surface water which is considered soft water. The hardness increases to mildly hard during the months of May - October when the demand increases and the water supply is a combination of surface and ground waters. During the past year, CWD's water hardness averaged 77 ppb for groundwater and 26 ppb for surface water. Hard water may cause ice cubes to be cloudy and leave water spots on glasses. Hardness is naturally occurring in water, generally from magnesium and calcium, which are both important to good health.