The City of San Angelo's 2015 annual financial report includes a table on the second to last page showing average daily water use history. It's pictured above:
The impact of the 47.5% water rate increase in September 2011 can clearly be seen as citizens reduced usage. Citizens went from using 14 million gallons per day in 2011 to 8.8 million gallons per day in 2015. That's a 37% drop in average daily water usage, exactly what City Council said it wanted.
Citing a desire to encourage conservation, council decided to generate 75 percent of the revenue needed to make payments by increasing water usage rates by $1.31 per 1,000 gallons and 25 percent of the revenue needed to make payments by increasing the base usage rate by 29 percent.Citizens doing what Council wanted "blew a hole" in the water budget. So City Council hired Raftelis at a cost of $107,000 to make the case for fixing the budget hole. That resulted in a five year plan where rates will rise another 55%.
Council increased rates again in January 2016 by an initial 11.5% of the planned 55%. The impact of that increase is yet to be seen.
Update 4-4-2017: Water use for 2016 increased to 10.04 million gallons a day. The increase occurred after the first 11.5% increase in water rates. An additional 11.5% increase hit on 1-1-2017.