A study from Stanford says “The cleanest drinking water is recycled”.
But the same study points that the engineers discovered that the compounds regulated by the EPA accounted for less than 1% of the harm to the ovary cells. [A test used to assess the overall toxicity of the water samples where] “Ideally, we picked up the effects of chemicals specifically measured by the EPA, as well as those that aren’t”.
In high school I recall being told the water used to water the school’s field within and around the running track was recycled water, thus not potable. Some of us said fuck it, and drank it anyway because it was right where we needed it (locker rooms too far). Now I have to wonder if that was backwards advice, or perhaps it was good advice and recycled water has improved. Or maybe not all recycled water is brought to the same quality.
It was good advice.
The basic goal for treated wastewater is to have a low amount of easily digestible carbon source food.
Then usually the goal is about reducing the amount of other nutrients as nitrogen, then phosphorus…
All of this designed to avoid an unbalanced overgrowth of microbes in the water body that receives the wastewater stream. Were dilution, the sun and natural microbial predation are expected to further stabilize the (waste)water and allow for the death of contagious disease carrying microorganisms.
In the last couple of decades the research focus also looks at maybe reducing the amount of micropullutants these wastewaters are carrying — like non degraded medicines or other substances that have been found to have nefarious effects on the environment and maybe humans. —research.
When the goal is recycling the water, consideration is made to the content of disease causing microorganisms, like E. Coli, Staph., and a wide miriad of parasites that the current modern world best practices (barely) keep at bay - like tenías, giardia, etc., etc., etc… And not much is known about wastewater and the spread of viruses (like the COVID one).
Recycled water can be improved, usually at a higher cost of treatment. And always regarding specific targets. The unknowns and unmeasurables are not considered.*
So, yes, not all recycled water is brought to the same quality.
…It was good advise.
EDIT: * nowaday, at research level there are a few million dollar plus equipments that are quite a bit thorough on measuring stuff. And the unknown unknowns can be quite more controlled. But at a legal level things are far from it.