I should have known. John Bengtson covers the Olvera Street and LA City Water Company locations in his book "Silent Traces: Discovering Early Hollywood Through the Films of Charlie Chaplin " (I'd only looked at his website):
He doesn't explain the changes to the water company building, but covers everything else:
copyright john bengtson
The above pages may be found
here
Note that Bengtson says that after the LA City Water Company moved to larger quarters, the building became the shop of F. See On. I didn't know that.
Also,
Historic Los Angeles Theaters notes that the 1894 City Directory lists a "Chinese Theater" on Marchessault St. near Alameda. That may have been in the old LA City Water Company building (I don't know when the water company moved out).
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