The majority of water in Oregon belongs to the public. However, water may be "appropriated for benficial use." (ORS 537.110) Oregon law regulates the construction and useage of domestic water wells. Sellers of property with domestic water wells are required to test the well and provide the results to a buyer within 90 days. Buyers of such properties should perform due diligence to ensure that the well is permitted (if required), that the well has a Well Identification Number, and that the water supply is sufficient for the buyer's intented use. Here are some resources:

[Oregon Well Report Search][3]

[[Oregon Accredited Well Water Testing Companies][4]

][5][3]: https://apps.wrd.state.or.us/apps/gw/well_log/Default.aspx