Mom, the problem is absolutely caused by the dairies. And, your wonderful TCEQ refuses to enforce the current regulations or pass new ones which will help alleviate the problem.
The phosphorus feeds the algae, which blooms and then dies. As it dies it decays and releases geosmin, which causes the taste and odor problem. The amount of science and studies that support what I'm saying is, literally, overwhelming and unanimous. Tarleton State even agrees.
It's expensive as hell to treat, and he city does a fantastic job dealing with the problem. Waco water is some of the safest in the state, thanks to the good Ags who run things paying such close attention to it. But above a certain threshold of geosmin, the taste and odor problem can't be treated any more with the current system. That's why the new plant is going in.
Unfortunately, local taxpayers are paying for the treatment costs and the new plant while the dairymen who are causing the problem are raking in money.
I'm no environmentalist, and certainly have nothing against the livestock industry, but this is a serious problem that needs to be addressed. Those of you who care need to be pressuring Doc, Kip and Jim to crack down on TCEQ.