What is the average annual water and sewer usage at Mason? Post author By Margaret Lo Post date January 23, 2018 Mason spends over $1 million a year on water and sewer. For fiscal year 2017 (July 2016 through June 2017), Mason spent $1.5 million on water and sewer and used over 179 million gallons of water. ← What is the average annual building energy use and cost at Mason? → How many “green” buildings are on campus?