To protect groundwater, the Agricultural Operation Practices Act (AOPA) requires manure storage facilities to be a minimum of 100 metres from a water well. Some sites, however, have geologic, topographical, or other characteristics that may prevent contamination of a well that is closer than 100 metres. The water well exemption screening tool provides approval officers with a consistent means of assessing the risk to a water well. If the assessment demonstrates that the water well won’t be affected by the manure storage facility, the approval officer may consider exempting the 100 metre distance requirement. The reasons for the exemption must be clearly explained in the decision summary issued with the permit.