The nitrate tests are provided for free by Clean Water, Land and Legacy Amendment funds at the Department of Agriculture. This particular water sample they are testing comes from someone’s private well that is used for washing dishes, bathing and drinking. The Department of Agriculture first started offering free nitrate tests in the 1990s for rural well owners, who are the most likely to be exposed to nitrates. A machine reads a nitrate level from a water sample at Farmfest in Morgan, Minn., on Aug. 4, 2026. The free tests aren’t just available at Farmfest: most Soil and Water Conservation Districts have their own nitrate clinics that people can use.