Water is a basic requirement for (most) life.
Water Supply is handled elsewhere.
Domestic water usage (based on USGS.gov datasheet, 6-DO), which includes indoor and outdoor use by residential buildings, average across the USA is, on average, 88 gallons per day per person. This ranges from 51 gal/day in Wisconsin, up to 167 gal/day in Utah. With an average of 2.58 people per household (2010 Census) that equates to an average of ~227.04 gallons per household per day. This doesn't include things such as industry and farm usage.
Total water usage across the USA in 2010 was estimated at 355 thousand million gallons per day, divided by the population of 313 million people equals 1134.185 gallons per day per person, or 413,977.6 gallons per person per year.
A lot of this is used in irrigation and thermoelectric power generation (115,000 Mgal/day and 161,000 Mgal/day respectively), which may be lower in an OCF community.
It should be noted that although the population has steadily increased, the overall water usage has decreased compared to the 1970s. This suggests that the nation is becoming more efficient with water usage, or that processes involving water usage are being reduced.