The Land Prioritization Mapping to Protect Drinking Water Quality (2025 Update) ranks land parcels in specific Mid-Atlantic states to protect drinking water quality and their potential to degrade long-term water quality.

The question asked in this five-year update remains the same as the original 2020 project, “Which parcels of land should be conserved to be most beneficial to drinking water?” However, the scope of this updated tool is much larger. Instead of focusing just on the Potomac River basin as the 2020 tool had done, the 2025 map was expanded to include the entirety of the states in which the basin sits—the District of Columbia, Maryland, Pennsylvania, Virginia, and West Virginia.