When your client buys a home, especially a farm and they have
more than well.
Many of the are shallow wells. (15-30 feet).
Shallow wells are notoriously known for contaminated water.
Do you test all the wells and if you find one that is bad what do yo do with that well?
It may be a fixable issue and maybe not.
But in my opinion, test them all and if they will not be used get them sealed!