I have still yet to hear about a water filtration system that could remove the medicines that make their way into our waters. It appears that the cost to implement such systems is prohibitive at this point, or at least not until many, many people are made sick from the medicines. Seeing as how they don't care to address side effects from the direct us of medicines, it's unlikely that they'll care to address this issue for a long time.
Many medicines now enter our water resources in their original form. Men and women who apply topical hormones via creams, wash those off down the drain on a daily basis. Antibiotics are being excreted in their original form. I used to be that our bodies would break them down. Now they're being engineered differently. New York city used to boast about it's water filtration system, but that boast went down the drain a couple of weeks ago when they discovered that the water was loaded with medicines.