Determine user groups for the various water fixtures, as not all occupants may be using all fixtures. For example, employee restrooms and customer toilets in a retail store have different usage patterns that would affect the water use calculations if the

Determine user groups for the various water fixtures, as not all occupants may be using all fixtures. For example, employee restrooms and customer toilets in a retail store have different usage patterns that would affect the water use calculations if the fixtures were different. For example: 

• 2 male staff using a 1.6 gpf toilet 3 times per day each = 9.6 gallons a day.
• 50 male customers using a 1.0 gpf efficient toilet  0.2 times per day each = 10 gallons a day.
• 9.6 gallons from the staff + 10 gallons from the customers = 19.6 gallons daily.
• If the staff got the more efficient 1.0 gpf toilet, and the customers got the less-efficient 1.6 gpf toilet, you would have employees generating 6 gallons and customers generating 16 gallons = 22 gallons daily, an increase.