It's an extremely basic process (bring in water from the Lake, let it settle, filter it, add some chlorine and flourine and pump it out again) but in some beautiful buildings. Here are some of my pictures (or take a look at a 'blog.to' link here). For a good 'guided tour' I liked the 'Torontoist' site - lots of interesting information. (Click any photo to enlarge)
Looking up to the filtration building.
One of the big front windows in the filtration building.
Rotunda in the filtration building.
(This was an interesting column. At the top on two sides the 'clock-like' dials show how full the water storage tanks used to backwash the filters are. One side is a clock. And one side shows something else about the water levels. Also an indicator light - red in the picture above - as to the readiness to clean the filters).
Control panel in the pump room.
Nice brass guardrails and chain.
The pump room
Part of the service building