In 1991, field studies were conducted to determine the effects of pH, calcium, alkalinity, hardness, and chlorophyll on the survival, growth, and reproduction of zebra mussel (Dreissena polymorpha). Water from 16 south-central lakes in Ontario was collected and supplied to zebra mussels in a flow-through system. Adult zebra mussel mortality was significantly correlated with calcium and pH. Growth rates of juvenile mussels ranged from -83.3 to 200 µm ·week-1. Water buffer variables (calcium, alkalinity, and total hardness) explained 60-66% of the variation observed in the change in shell length of juvenile zebra mussel (p = 0.001-0.003). There was negative growth at calcium levels less than 8.5 mg Ca · L-1, alkalinity levels less than 17.1 mg CaCO3 · L-1 and total hardness levels less than 31 mg CaCO3 · L-1. Maximum growth occurred at calcium levels of 32 mg Ca ·L-1, alkalinity of 65 mg CaCO3 · L-1, and total hardness of 100 mg CaCO3 · L-1. Positive growth of juvenile zebra mussel only occurred at pH levels greater than 8.3. Only one veliger survived to the settling stage.