The impact that unsafe water can have on a community varies.
High levels of bacteria in drinking water can lead to infection and cause health officials to issue a boil order.
Fluoride, nitrogen, lead and copper don't typically pose health risks to normally healthy people unless they are at high levels, he said.
High levels of nitrogen can affect the oxygen levels in the blood of newborns and people with kidney and liver problems. Copper can also pose a risk for people with liver ailments.