Enviro sci fag here. sounds gross would be fine if ran through wastewater plant first then drinking water plant/ they can't just run non treated sewage through drinking water plant it would fuck the plant up severely… now DISCHARGE of "treated" sewage effluent would be bad as its not treated for crypto sporidium ect. but honestly there is no easy wat to link it into the systems they would have to run pile. big pipes. miles to link the shit. people would know bigtime. However there is one big big thing people don't know. your municipal water isn't treated worth a fuck. they don't magically tremove most heavy metals, they DO add lots of fluoride and derivatives.. and ALL medication that makes its way into groundwater or the surface source does not have pharmaceuticals removed. If you really knew you would home distill.
To continue. single stage units can be made or bought. ( $1800 lab quality)
Good double stage units are $2800-$5000)
Thats for serious lab quality pure H2O
https:// www.ebay.com/i/152979246518?rt=nc&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D1%26asc%3D20160908110712%26meid%3Dda24972022184fd386ce968219784e56%26pid%3D100677%26rk%3D4%26rkt%3D6%26sd%3D302595878510%26itm%3D152979246518