As a former firefighter I can appreciate the Water Department's efforts to maintain and upgrade fire hydrants throughout the city. However, I don't think it is necessary to repaint the fire hydrants from the standard high-visibility yellow to white.
Perhaps the new color is more visible at night to assist firefighters in locating the fire hydrants, even though blue reflective tiles in the street have long been used to identify fire hydrant locations regardless of the color they are painted.
The cynic in me might conclude that the city is "white washing" the lack of residential street and sidewalk repairs, by changing the color of the fire hydrants to make it more obvious they were freshly painted.
Save the paint and fix the streets.