The problems of user charges as a device for regulating the discharge of pollutants are considered for the Miami (Ohio) river basin. Cost functions for treatment processes are estimated for this basin. The analysis indicates that if taxes are levied to achieve the minimum cost of meeting a water quality standard, the receipts would pay about 85% of the cost of centralized treatment. However, user charges levied to pay for centralized treatment would erase this deficit at an additional total cost of only about 1%.