https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=25166
Only taken a decade!
https://www.ebay.co.uk/itm/10W-Tap-Water-Home-Voltage-Regulation-DIY-Small-DC-Accessories-Hydro-Generator/254610458538?hash=item3b47f747aa:m:mURy61TEpu4RsDO2j_JtKDQ
Regards
BOD