Science to Live By: Water: Life’s Elixir (Part Four)


© J. Dirk Nies, Ph.D.

“Come on ‘Lito,’ run under the rainbow!” my three-year-old granddaughter exclaimed to me as she sprayed a mist of water from the garden hose into the bright summer sunshine. Water is essential for life, and on a hot afternoon, it is a delightful source of refreshing enchantment too.

Like the air we breathe and the food we eat, we need fresh, clean water to live. To supply this basic human need, we have built a vast, interconnected public and private infrastructure to impound, filter, treat, store and transport water to and throughout our homes and businesses, and after use, to properly return this water back to the environment. Through these investments we have achieved the wonderful blessing of water on demand. At the mere turn of a faucet handle or the twist of a garden hose nozzle, we have running water in abundance. Water we can use for drinking, cooking, washing, watering, sanitation, fire protection—and making rainbows.

Because these waterworks function so well most of the time, our technological prowess can lull us into complacency. For if we had to garner by hand all the water we use —customers of the Albemarle County Service Authority use about 1.6 billion gallons (6.7 million tons) of water per year—we would be more aware, perhaps acutely aware, of how precious it is. We also would likely be more attentive to just how much work and energy is required to make all the water we use so readily available.

Across the country, the average American household uses 320 gallons per day according to information available from WaterSense, a program run by the Environmental Protection Agency that seeks to protect the future of our nation’s water supply. That’s 100 gallons of water per person – enough for each of us to fill 1,600 drinking glasses to the brim every day. (For more information on water usage, water-efficient products and appliances, and water-saving tips in and around our homes, visit

Locally, C’ville residential customers of the Charlottesville Public Utility Division of the Rivanna Water and Sewer Authority use on average 478 cubic feet (3,575 gallons) of water per month, or about 118 gallons per day. That’s less water than the national average for a household, and that’s good, but it’s still a lot of water. Imagine getting hold of 118 gallons of water by hand. Using a 5-gallon bucket, a bucketful of water would weigh more than 40 pounds, and I know that if I had to fill it and lug it indoors two dozen times each day, day after day, it would surely capture my attention, if not my mind, and most assuredly my back!

Do we need this much water to live our lives well? Let’s take a look at our activities and habits to see where all that water goes. As we do, I will suggest tips that can save water. (Calculate your water use patterns using the Charlottesville Residential Water Calculator available at and begin conserving water in ways that work for you.)

Sanitation and bodily cleanliness are signature achievements of modern civilization, and not surprisingly, it is within our bathrooms that we use the most water—an estimated 50 percent or more.

Flushing the commode is the single largest use of water in our homes. Depending upon the model, each washing out and refilling of a toilet uses 1.5 to 3.5 gallons, with older models using up to 7 gallons. The City of Charlottesville offers residents a $100 rebate for the purchase and installation of an efficient WaterSense certified toilet.

When we run the bathroom faucet, we use anywhere between 0.5 to 5 gallons of water per minute. Turning on the tap only when needed during brushing teeth or shaving can save more than 200 gallons of water per month.

Prior to 1980, many showerheads exceeded a flow rate of 5 gallons per minute. Now most restrict water flow to 3 gallons per minute maximum. At this flow rate, over the course of a 7-minute shower, 175 pounds of water will have streamed through the showerhead. As a household rule, we each strive to shower using less water than we weigh.

Taking a bath in a full tub of water can use twice the volume of water as a shower. When drawing water for a bath, don’t wait for the water from the tap to reach the desired temperature, stopper the drain immediately and adjust the temperature of the bath water as the bathtub fills.

Cleaning clothes represents another large expenditure of water. A standard domestic washing machine uses 45 to 55 gallons (that’s 375 to 460 pounds of water!) per load. Water-conserving, front-loading models use about 20 to 25 gallons per load.

Cleaning up after meals also involves a lot of water. Dishwashers use 5 to 15 gallons per load. Unless you can hand wash a full dishwasher load of dishes in under 7 minutes (7 minutes x 2 gallons per minute flowing through the kitchen sink faucet = 14 gallons), operating your automatic dishwasher without pre-rinsing probably is more water efficient.

A disconcertingly large amount of residential water is lost through leaks. Across America, our dripping faucets, running toilets and leaky pipes waste more than 1 trillion gallons of water each year (more than 11,000 gallons per household) according to EPA’s WaterSense. A leaking toilet typically is the single biggest waster of household water. A faulty shut-off valve or leaky toilet flange can squander upwards of 200 gallons of water every day. To see if a toilet is leaking, put a drop or two of food coloring in the tank. If the color appears in the bowl without flushing, it leaks.

In Virginia, roughly 30 percent of our household water is devoted to outdoor uses, more than half of which goes toward watering our lawns and gardens. Our water use jumps 20 percent in the summertime when plant needs are highest. Unfortunately, inefficient watering habits often result in losing half the water we shower on our landscapes to evaporation.

Here are three water-wise landscaping suggestions to consider. Spend a little extra to improve the water-retaining properties of the soil when planting annuals, perennials or shrubbery. Plant regionally appropriate, drought-tolerant and native plants so that the landscape can be maintained with normal rainfall supplemented with strategic watering as needed. And group plants with similar watering needs into designated “hydrozones” to facilitate watering to each zone’s specific requirements.

The true value of fresh water is priceless. We are so very fortunate to have access to adequate supplies of clean water and to have available the energy and infrastructure to deliver this water to our homes and businesses. Prudent use of water will help protect and manage our watershed and hydrological resources. By using water wisely, we will save energy too. Best of all, our grandchildren and their children’s children will be grateful that we did.

*“Indoor Water Use in the United States,” Document EPA-832-F-06-004, June 2008.