[ttyprintk]

Those would be valuable to know, but I bet separating the non-point-sources is unachievable. I mean, we may be detecting latent (> 1 year old) hydrological concentrations from the combination of lawn, ag, failing septic tanks, and point sources that conveniently become non-point.

On that last source: the design is to concentrate liquid manure, which as a point source is a liability, and spray it over an area. I believe this makes it a non-point-source for the purposes of carveouts in the clean water act.