Pub. L. 92 - 500 , October 18 , 1972 ; as amended by the Water Quality Act of 1987 , Pub. L. 100 - 4 , February 4 , 1987 .
Federal Water Pollution Control Amendments of 1972 .
Pub. L. 92 - 500 , October 18 , 1972 ; as amended by the Federal Water Pollution Control Amendments of 1972     of 1987 , Pub. L. 100 - 4 , February 4 , 1987 .
Federal Water Pollution Control Amendments of 1972 .