The average person in the U. S. uses between 100 and 250 gallons of water a day. I know it is possible to get by just fine on one tenth that amount. The use of low water capacity toilets, flow restrictors at shower heads and faucet aerators are fairly common now. More radical conservation approaches include diverting gray water from bathing, clothes washing and bathroom sinks to watering plants; catching rain water from roofs and paved areas for domestic use and switching to composting toilets. These can be very effective and safe means of water conservation if done carefully to avoid bacterial infestation; be sure to comply with all local laws that regulate these strategies.
The average U.S. household equipped with low-flow toilets saves 25 gallons of water per day, or more than 9,000 gallons per year.