On average, our society uses almost 100 gallons of drinking water per person per day. Traditionally, water use rates are described in units of gallons per capita per day (gpcd), gallons used by one person in one day. Of the “drinking water” supplied by public water systems, only a small portion is actually used for drinking. As residential water consumers, we use most water for other purposes, such as bathing, toilet flushing, cooking, cleaning, and lawn watering.
The amount of water we use in our homes varies during the day:
Lowest rate of use – 11:30 p.m. to 5:00 a.m. rise/High use – 5:00 a.m. to noon. (Peak hourly use from 7:00 a.m. to 8:00 a.m.)
Moderate use – noon to 5:00 p.m. (Lull around 3:00 p.m.)
Increasing evening use – 5:00 p.m. to 11:00 p.m. (Second minor peak, 6:00 to 8:00 p.m.)
We use tap water for various purposes. A typical family of four on a public water supply uses about 350 gallons per day at home. In contrast, a typical household that gets its water from a private well or cistern uses about 200 gallons for a family of four. In our communities an additional 35 gallons of water are used for public activities such as fire fighting, street washing, and park maintenance.