Thursday, April 26, 2012

Water Conservation and Household Use of Water in America

The United States as a nation possesses abundant water resources and has developed and used those resources extensively. The good news about water is that “on average” the United States uses less than 8% of the water that falls as precipitation within our borders annually. Unfortunately, precipitation varies from the average significantly on a regional basis.  With the exception of western, coastal regions of Washington, Oregon, and northern California, the western United States is arid and receives less annual precipitation than the rest of the nation, but water use is no longer tied to local precipitation. For example California uses 4,470,000,000 gallons of water per day for domestic consumption alone; it also uses 24,400,000,000 gallons of water per day for irrigation and would use more if it were available.

Traditional water management in the United States focused on moving or storing the country's abundant supplies of freshwater to meet the needs of users. The era of building large dams and conveyance systems has drawn to a close. The disruption of natural ecologies, environmental regulations, and the sheer cost of building the massive water projects has made them impossible. In the 21st Century, the regional limitations of the water supply and established infrastructure must be managed more effectively to meet increasing demands. "New" future supplies of water will come from conservation, recycling, reuse, and improved water-use efficiency rather than from ambitious development projects.

The future health and economic welfare of the Nation's population are dependent upon a continuing supply of fresh uncontaminated water. According to the US Geological Survey combined domestic private wellwater usage and public-supplied deliveries to homes totaled 29,400,000,000 gallonsper day in 2005, and “average” US citizen uses 98 gallons a day of water for domestic use, which includes, bathing and bathrooms, laundry, cooking, drinking and outdoor use. Outdoor watering in the drier climates causes domestic per capita use to increase in the driest and hottest climates. In Nevada, average domestic water use was reported to be 190 gallons/day per person, while in Maine they used on average 54 gallons/ per day. We have the most control over the amount of water we use in our homes and weather alone does not explain the different water usage rates. In Maryland average domestic water use was reported to be 109 gallons/day per person while in adjacent Virginia the average water usage was 75 gallons/day per person. Pennsylvania to the north uses an average of 57 gallons/day per person. The US Geological Survey who collected and compiled all this data and the estimates imbedded in them offers no explanation for the differences in domestic water use.  While I believe there are differences in water usage, I do not know the causes of the variation beyond the weather, but the age of the water fixtures can contribute to the differences.

There are tremendous differences in water consumption of appliances and fixtures based on their age and design. For example we all know about low-flush toilets which use 1.6 gallons per flush versus 5 gallons per flush for the older toilets. According to the 2001 Handbook of Water Use and Conservation by A. Vickers and published by WaterPlow Press in Amherst, MA the average person flushes the toilet 5.1 times a day. Before the advent of low flush toilet, flushing was the largest use of water for each person. If you have new toilets your daily water use for flushing would be 8.2 gallons versus 25.5 gallons for an older toilet. Compressor assisted toilets (commonly used in highway rest stops) only use 0.5 gallons of water and if widely adopted could reduce flushing use of water to 2.6 gallons per day per person. Other toilets that have separate flush cycles for fluid can also save water, and of course there is the California strategy of not flushing after only urinating to minimize the daily number of flushes. Changing your toilets and flushing behavior turns out to be the single most effective water conservation strategy. Thank goodness, there are now powerful flushing low flow toilets. 

The typical American uses the most water for flushing, showering, washing hands and brushing teeth, and laundry. Buying water efficient appliances and fixtures and changing behavior can significantly reduce our water use. For bathing and brushing teeth low flow faucets and showerheads and behavior modification (not running the water while you brush your teeth, shorter showers or not running the water while you lather up can save about a third of the water typically used for personal hygiene, reducing the typical 28 gallons a day to 19 gallons a day. Laundry is the second largest use of water after toilets. According to Dr. Vickers the typical American does 0.37 loads of laundry per person per day. A top loading washing machine uses 43-51 gallons per load while a full size front load machine uses 27 gallons per load and some machines have low volume cycles for small loads that use less. Replacing a top load washing machine with a front load machine saves 6-9 gallons of water per person per day or 24 gallons per load of laundry. A standard dishwasher uses 7-14 gallons per load while a water efficient dishwasher uses 4.5 gallons per load. Eliminating the watering of our ornamental gardens would significantly reduce water use especially in the most arid parts of the country where there is the most pressure on water supply. According to Dr. Vickers, by replacing appliances and fixtures with water efficient fixtures and eliminating outdoor use of water the typical American could reduce their water use to about 38 gallons per person per day. That is a significant water savings.

For people on public water supplies reducing domestic, indoor water use saves money on the water bill. The average cost of water nationally is reported to be under a penny a gallon, but that still adds up when you consider that going from 98 to 38 gallons of water per day would save 21,900 gallons of water per person per year. For my household on well water the concerns are different. My well draws fairly shallow for a Virginia well, my pump is at about 100 feet. The aquifer is unconfined and the water level will change with the seasons and drought. Natural groundwater levels usually reach their lowest point in late September or October. The highest levels tend to be during March and April, but this year was particularly dry until late April and it remains to be seen if this will be a dry year. Groundwater levels usually fall in May and continue to decline during summer as the trees and plants use the available water. Many well owners are very conscious of our water use because of the worry of the well going dry. Water conservation can help prevent a well from being pumped dry and can be used along with scheduled use to live with a low producing well.     

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