Water, Water Everywhere, But Getting Scarcer By the Day
Of all the water we use in Texas, about 60 percent is groundwater, and the other 40 percent is surface water. For North Texas, more than 90 percent of water supplies come from surface water resources, but the state has about 500 times more water underground than anything we see on the surface, and all the water in Texas rivers and lakes makes up just 0.2 percent of the total. No river in Texas gets less than 15 percent of its flow from groundwater, and there are about 6,700 dams and reservoirs. Only Caddo Lake formed naturally.
The average total home water use for each person in North Texas is about 100 gallons a day. During medieval times, a person used only five gallons per day. Two-thirds of the water we use indoors is in the bathroom. About two gallons of water are used when you brush your teeth. Flushing a newer toilet uses less than two gallons per flush. Older models require three to seven gallons. A 10-minute shower with a water-efficient showerhead uses 25 or less gallons of water. The average cost of drinking water from the tap in North Texas is about $2.50 per 1,000 gallons, which equals about four gallons for a penny. A leaky faucet can waste 100 gallons a day.
An acre-foot of water, the volume on an acre of land covered 12 inches high, is about 326,000 gallons. One-half of an acre-foot of water is enough to meet the needs of a typical family for a year. Texans use about 16.5 million acre-feet per year. It takes 3.3 acre-feet of water to grow enough food for an average family for a year.
Looking beyond our borders, there is the same amount of water now as there was when the Earth was formed, and it is the only substance found naturally in three forms: solid, liquid, and gas. Close to 97 percent of the world's water is salty or otherwise undrinkable, while 2 percent is locked in ice caps and glaciers, leaving 1 percent for all of humanity's agricultural, residential, manufacturing, community and personal needs. Water also regulates the Earth's temperature. A person can live about a month without food, but only about a week without water.
For more information, visit TexasWater.tamu.edu/faqs.