Urine? Well, yes, but also the feces and the nasty water from industry. As someone has pointed out already, if your WTP collects from the river, you are already drinking treated sewage water.
At our plant, we have a water reclamation facility at the end of our process, the same type of facility used at the water treatment plant upstream. A WRF is common, iirc, in CA, but is, afaik, the first of its kind here in MN. It is far more common to discharge without the additional filtering and contaminant removal provided by a WRF.
The water we discharge is tested biweekly for ammonia and phosphorus and daily for total coliforms and biological oxygen demand. Ammonia and coliforms are non-detectable ~99% of the time. We are doing a very good job turning sewage into drinking water for the next town on the river.
/lab intern at a WWTP