How would you even go about enforcing this?
Do you know how much un-permitted construction goes on? More than you probably think. My point is that it's a non-starter: people just aren't going to do it and they'll get away with it unless there's some sort of third party involvement like a sale or maintenance.
Frankly, it’s good practice to know where humans are getting their potable water from considering potential pesticide, PFAS, and heavy metal contamination. Cheaper than health issues (cancer, primarily) and premature death that could’ve been avoided with well surveillance processes, as well a children consuming contaminated water potentially handicapping them for life. This very piece describes this in detail, and how without regulation, this harm at scale continues (because it’s easier to ignore than to protect).
The tools exist to solve for this. As always, it’s will (or lack thereof). Do we care about these people or not?
Might have better luck imposing testing on rental properties.