The South Nation River watershed has a regulated water quality trading program. Legally, wastewater dischargers must not discharge any increased loading of phosphorus (P) into receiving waters. New wastewater systems are now choosing trading instead of traditional P removal technology, and point source dischargers are buying P credits from rural landowners, primarily farmers. These credits are generated by constructing nonpoint source pollution control measures. Mathematical formulae are used to calculate the credits of P removed by each measure. A successful trading program requires several conditions, including community agreement, legislative backing, credit and cost certainty, simplified delivery and verification, written instruments, and legal liability protection. South Nation Conservation, a community-based watershed organization, is the broker handling the transactions for these P credits. The program is run by a multi-stakeholder committee, and all project field visits are done by farmers and not paid professionals. An independent evaluation showed higher opinions for the broker and regulatory agency, and most farmers were willing to, or had already, recommended the program to other farmers.