Another Farmfest attraction: free nitrate water testing for private well owners

The machine is a clunky piece of gray plastic about the size of a briefcase. Clear tubes pump yellow-tinted water from a small cup into the machine, called a spectrophotometer, where an ultraviolet ray shoots light through the sample to measure its wavelengths. Wait thirty seconds, and the machine’s screen flashes a number: 7.2. 

Denton Bruening, a Minnesota Department of Agriculture employee and the machine’s operator, adds the number to a piece of paper with the results of about 40 other water samples dropped off by Farmfest attendees that day. 

The agency is at Farmfest this week to test people’s drinking water samples for nitrate contamination, which is often caused by fertilizer and manure runoff from farms. Most people stop by the booth with Ziploc bags filled with water on their way to the other offerings Farmfest is famous for: delicious corn dogs, tractor salespeople and a chance to rub shoulders with politicians.

The nitrate tes...