Never heard of the "Board of Water Commissions" (I lived in the area for about 25 years, a long time ago).
Per this:
https://detroitmi....sources/about-dwsd It should be Board of Water Commissions, which is still a term that's not well-known in Detroit. Instead, they call it the Dept of Water & Sewerage.
They were & are a big deal, as they supply drinking water to communities well-outside of Detroit, and despite all the chronic, acute problems Detroit had/has, drinking water quality has pretty much remained stellar.
I'm definitely curious about it's history & the reason for the high ceilings & open spaces -- maybe to store/repair large infrastructure, some sitting on trucks/trailers & needing cranes, etc. to move?
It couldn't hurt to call the City Historian, or the Water & Sewerage Dept Facilities Management and just tell them you're interested in unique buildings/architecture & their history (don't call it an old, abandoned building -- you may hurt their feelings -- and don't tell them you poked around inside, or-else you're now a vandal/scrap-metal suspect) & ask about the place.
If you have it's street address, you could also look it up in old property records & maybe phone book listings.
I assume you've seen the old Detroit Fire Dept maintenance/storage facility. I recall it being in a similarly old, large open-space warehouse in that area.
/-/ooligan
Downtown Detroiter 1997-2002