How many of you provide water quality testing?
If you do, do you send it to a lab, take it to a local establishment or use the DIY kits from Lowe’s or Home Depot?
Find a local “state certified water quality testing laboratory” and go talk to them about taking samples to the correct protocol, would be my recommendation. Typically, they will have it written out as well as the pricing for different choices of what to test for. I have had some where the buyer wanted testing that required sending the sample to the university downstate for results.