I was looking into this DIY approach and it is not allowed in my county. Some of the justification is that improperly cased wells can allow backflow contaminati

I was looking into this DIY approach and it is not allowed in my county. Some of the justification is that improperly cased wells can allow backflow contamination of the larger water supply, affecting other nearby water sources. I'm not sure how likely this is as I have limited knowledge of the subject.