With droughts and water shortages slated to affect ever-larger portions of the United States, more and more people wonder how they can meaningfully make a difference.
Lots of websites offer water-saving tips, but which actions actually conserve meaningful volumes of water? And which offer the most conservation bang for the buck?
A new study out in the July-August issue of Environment provides some helpful, well-researched answers, and happily the bottom line is reassuring: by taking simple, practical actions, a household can cut its indoor water use by 60% and its outdoor water use by 10-100%.
Using the best data sources available, policy analyst Benjamin D. Inskeep and Shahzeen Z. Attari, an assistant professor at the School of Public and Environmental Affairs at Indiana University in Bloomington, methodically estimated the water that would be saved if a theoretical 2.6-person household took various actions.
Importantly, the researchers distinguish between technology upgrades, such as buying a more water-efficient showerhead, and behavior changes, such as taking a shorter shower. Both save water, but for any given activity sometimes the behavior change saves more than the appliance or fixture upgrade, and sometimes the reverse is true.
Before getting to the list, a couple background facts: the average 2.6-person US household uses 255 gallons of water per day. On average, 71 percent of that use is indoors and 29 percent is outdoors. In the drier western part of the country, households that have thirsty lawns and landscapes can use 50-70 percent of their water outdoors and, as a result, have much higher water use overall.
Tackling indoor water use first, here’s what Inskeep and Attari found to be the five most effective conservation actions a household could take, along with the percent of indoor water that action would save:
- Replace standard toilets with WaterSense-labeled toilets (19%).
- Replace clothes-washer with an Energy-Star-labeled washer (17%).
- Reduce showering time from 8 minutes to 5 minutes (8%).
- Wash full loads of clothes (8%).
- Reduce toilet flushes by one-fourth (7%).
Taken together, the five fixture and appliance upgrades the researchers analyzed – toilets, clothes washers, showerheads, faucets and dishwashers – could reduce indoor water use by 45%. But you get can get a 35% reduction just by upgrading your toilet and clothes washer, the two biggest-ticket items.
Behavior changes do make a difference, too. In fact cutting your showering time to 5 minutes from 8 saves more water than replacing your standard showerhead with an efficient one. Of course, you could do both.
And don’t forget that saving water indoors not only cuts your water bill (and helps keep water in your local river, reservoir or aquifer), it saves energy, too. Any time you reduce the use of hot water you’re cutting your energy bill, as well.
Moving outdoors, water-savings estimates get more complicated due to the wide variations in climates and landscapes across the country. But with irrigation being the single biggest end-use of household water, it’s crucial to consider effective ways to curb water use outdoors.
Here are five of the most effective options analyzed by Inskeep and Attari, along with the range of outdoor water savings possible from each:
- Don’t water your lawn: let it go dormant in summer (up to 100%).
- Irrigate plants and grass with water you collect in a rain-harvesting system (up to 100%).
- Replace most plants and grass with climate appropriate (water-wise) landscaping, and irrigate no more than necessary (20-100%).
- Replace cool-season turf grass with a warm-season, native or low-water-use variety (20-100%).
- Install a soil moisture sensor to determine when to irrigate (11-92%).
Becoming a water-conserving household may cost some money. But besides the satisfaction of being a good water steward, your investment will typically pay you back within a few years, depending on your water and energy costs. According to an EPA-funded study mentioned by the authors, the typical household will spend $1,584 to upgrade to water-efficient fixtures and appliances, but the savings on water and energy bills will pay this amount back in six years.
Some water utilities will actually compensate you if you rip out your lawn and replace it with water-conserving landscaping. The Southern Nevada Water Authority, which serves Las Vegas, rebates its customers $1.50 for every square foot of turf replaced with desert landscaping. And in June, the Los Angeles Department of Water and Power announced a boost to its “cash in your lawn” rebate, upping it to $3 per square foot of turf replaced with drought-tolerant plants.
Though rebates and incentives do help, in most cases saving water at home makes sense – and cents — anyway. The short-list of home water-saving measures Inskeep and Attari have pulled together is a great place to start.
Two final ideas: don’t forget about the other components of your personal water footprint, especially your diet and energy use. Check out our National Geographic water footprint calculator.
And second, make a pledge to take some action to conserve at changethecourse.us. For every pledge (it’s free) we return 1,000 gallons to a depleted part of the Colorado River Basin. Join us!
Sandra Postel is director of the Global Water Policy Project, Freshwater Fellow of the National Geographic Society, and author of several books and numerous articles on global water issues. She is co-creator of Change the Course, the national freshwater conservation and restoration campaign being piloted in the Colorado River Basin.