For now, all contaminants are regulated individually, as that is the way scientists traditionally calculate public health threats. In the real world, each of us is exposed not just to one contaminant, but to tens of thousands. See environmental estrogens . Triazines are currently present in both ground and surface waters. These and other triazines are a cheap way for farmers to kill a wide range of weeds.
Chloroform is the best known example.
THMs cause 10,000 cases of colon and bladder cancer annually. The chlorine industry strenuously opposes closer regulation of THMs. Turbidity in water can be harmless, or it may indicate to water engineers that extra filtration, flocculation, and sedimentation is needed. It's a promising technology, but UV isn't applicable to murky waters that the light cannot penetrate.