Determine user groups for the various water fixtures, as not all occupants may be using all fixtures. For example in an elementary school, teacher restrooms and student toilets have different usage patterns that would affect the water use calculations if

Determine user groups for the various water fixtures, as not all occupants may be using all fixtures. For example in an elementary school, teacher restrooms and student toilets have different usage patterns that would affect the water use calculations if the fixtures were different.  For example: 

• 2 male teachers using a 1.6 gpf toilet 3 times per day each = 9.6 gallons a day.
• 50 male students using a 1.0 gpf efficient toilet 0.5 times per day = 25 gallons per day.
• 9.6 gallons from the teachers + 25 gallons from the students = 34.6 gallons daily.
• If the teachers got the more efficient 1.0-gpf toilet and the students got the less-efficient 1.6-gpf model, you would have teachers generating 6 gallons and students generating 40 gallons = 46 gallons daily, an increase.