Walkerton contaminated for a long time
Groundwater in the Walkerton area was contaminated as far back as 1978.
An Environment Ministry official says the town was advised to buy the farmland around one of the area's wells, because agricultural runoff was already poisoning the groundwater.
Willard Page was the Environment Ministry's district manager from 1974 until 1997.
He told the inquiry into the tainted water tragedy that Walkerton was advised to establish a water protection zone around Well Five.
Agricultural runoff into that particular well has been identified as the source of the E.coli contamination of Walkerton's drinking water last May.