1. (a) Streams. The permittee must collect background samples at a point away from the stream bank, as close as is feasible to the channel, immediately upstream of the point of discharge, but not affected by it.
2. (b) Lakes. The permittee must collect background samples at a point away from the water’s edge and outside the regulatory mixing zone.

Added at 41 Ok Reg, Number 23, effective 9-15-24