Water EfficiencyF O R Y O U R H O M E

Third EditionRocky Mountain Institute

Products and advice whichsave water, energy, and money

Water Efficiency for Your Home:

Products and Advice Which SaveWater, Energy, and Money

Third Edition

John C. Woodwell, Jim Dyer, RichardPinkham, and Scott Chaplin

Rocky Mountain Institute is a nonprofit researchand educational foundation. Our goal is to foster theefficient and sustainable use of resources as a path toglobal security. If you would like a free publicationslist and more information about RMI’s other areas ofresearch—energy, agriculture, economic renewal,transportation, green architecture, and security—please write to us at 1739 Snowmass Creek Road,Snowmass, CO 81654. RMI appreciates your tax-deductible support.

Rocky Mountain Institute gratefully acknowledgesresearch grants in support of its water research from:

Ruth H. Brown FoundationWilliam H. Donner FoundationGAG Charitable CorporationGeorge Gund FoundationWilliam and Flora Hewlett FoundationJoyce Mertz-Gilmore FoundationNew-Land FoundationJessie Smith Noyes Foundation777 Fund of The Tides FoundationWallace Genetic Foundation

RMI does not solicit or accept fees from any manu-facturer or vendor and does not advertise for, or makeany claims regarding the performance or other charac-teristics of, particular products. Some data on perfor-mance have been provided by manufacturers andhave not necessarily been independently verified byRMI.

RMI has used ordinary professional care in prepar-ing this publication. The Institute and its employeesaccept no responsibility for the direct, indirect, or inci-dental consequences of any errors or omissions. Actualsavings to the consumer may vary from the savingsstated here.

Copyright (C) 1995 Rocky Mountain Institute. All rights reserved.

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ForewordThis booklet is published by Rocky Mountain

Institute to help individuals improve the waterand energy efficiency of their homes and savemoney in the process. New products and tech-niques allow today’s households to use a thirdless water than those of a decade ago, withoutsacrificing comfort or changing lifestyles.

Although this booklet is designed for homeowners and tenants, the ideas it advances can beapplied on a larger scale: your neighbors, com-munity, and water utility can all take advantageof the broad benefits that efficiency provides. TheCommonwealth of Massachusetts, City of LosAngeles, and communities and utilities across thecountry now encourage water-efficient productsand practices. Your community can do the same.

Rocky Mountain Institute’s resource-efficient headquar-ters in Old Snowmass, Colorado.

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The Wider Benefits ofEfficiency in Water Use

You can save a lot of water, energy, and moneyby using water efficiently. Today’s state-of-the-artefficient fixtures provide service equal or superi-or to their old, inefficient counterparts, but don’thave to cost any more. By facilitating efficientwater use, the advice and devices mentioned inthis booklet can:

• Cut your water and sewage fees by 35% ormore.

• Improve the quality of your shower, andallow twice as many people to get a showerbefore the hot water runs out.

• Cut your annual water-heating bill by$20–40 (up to three times this amount if youheat water with electricity).

• Reduce or eliminate the problem of an over-flowing cesspool or septic tank (or the ulti-mate headache, a backflowing toilet), poten-tially saving the hundreds of dollars itwould cost to build or expand a leachfield.

• In new construction, enable you to install amuch smaller septic leachfield than youwould otherwise have to install, with hun-dreds of dollars in savings.

• In new construction, allow you to savemoney by installing a smaller water heater(if you had planned to install a 50-gallonheater, a 30-gallon heater may be more thanlarge enough if you use efficient fixtures).

• Protect the environment. Water not con-sumed can save a river from a dam and wet-lands from destruction, while water notheated with fossil fuel means oil or gas notdepleted, coal not burned, carbon notreleased to cause global warming, and sul-fur not deposited as acid rain.

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Here’s Where YourResidential Water Goes

U.S. indoor residential water use is estimatedto average 80 gallons per person per day inhomes without efficient fixtures. Outdoor usevaries tremendously: your use could be insignifi-cant or, if you have a large lawn which requireswatering, it could be more than 200 gallons perperson per day. To be certain, compare your win-ter and summer water bills.

Save Water, PainlesslyIf your water use is anywhere near the nation-

al average, you can probably save a third or moreof the water you now use at home. The easy pro-gram described in this booklet will show youhow. Replacing your water-wasting fixtures withefficient state-of-the-art products will be an easy,money-saving project. Redesigning your land-scape with colorful, durable, native, and drought-resistant plants will be equally rewarding.

Start your retrofit program with your shower-head. The money saved on your water-heating

Washing Machine (22%)

Baths (9%)

Dishwasher (3%)

Faucets (12%)Showers (21%)

Toilets (28%)

Toilet Leaks (5%)

Typical inefficient indoor use:80 gallons per person per day

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bill, in addition to the savings on your water andsewer bills, will repay your investment in lessthan a year. The money you save on reducedenergy use can in turn finance the rest of yourretrofit program.

To learn where you can save more water, readon.

Showerheads: Save Water and Energy,Too

For less than $20, you can cut the water use ofyour conventional showerhead by 25–75% with-out sacrificing the quality of your shower. Ifyou’re using a conventional showerhead with anoptional washer or flow restrictor to limit itsdelivery, you can still save more water and sub-stantially improve the quality of your shower byremoving that device and using a high-perfor-mance showerhead instead.

To check the flow rate of your existing shower-head, turn the shower on all the way and see howlong it takes to fill a one-gallon plastic jug. (Youmay have to cut a piece of the neck off the jug soit will fit over the showerhead.)

Time to Fill Jug (sec) Flow (gpm)

10 6.015 4.020 3.024 2.530 2.0

If your showerhead fills a one-gallon jug infewer than 24 seconds, it’s using more than 2.5gallons per minute (gpm) and should be replacedwith a more efficient model. If the jug takes morethan 24 seconds to fill, you already have an effi-

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cient showerhead.The flow rate of your old showerhead, the

number of people taking showers, the length ofthose showers, and the price you pay for energyand water all will affect your financial savings.Annual savings of $20–40 are common for a fam-ily of three people—your savings may be twice orthree times this amount if you heat your waterwith electricity, which is more expensive thannatural gas.

Those savings make a $20 low-flow, high-per-formance showerhead an excellent financialinvestment: $20 in a 7% certificate of deposit takes10 years to return $20 in interest, while a savingsaccount takes more than 20 years to do so. In 10years, your efficient showerhead will easilyreturn 10–40 times its cost in saved energy alone,not counting the value of the saved water.

There are many excellent showerheads on themarket, but not all are as efficient as thosedescribed here. When buying a showerhead, besure that it delivers no more than 2.5 gallons perminute; 1.5-2.0 gpm will save you even more. The

3% 7% 100% 350%0

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It makes good economic sense to invest in a water-efficient showerhead.

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“feel” of the shower—misty, pounding, etc.—varies widely with brand and model (some havea needle-like spray that may drive you out of theshower!). Some models have a fingertip valve soyou can reduce the flow while soaping up with-out changing the temperature.

Your hardware or plumbing-supply storeshould carry water-efficient showerheads, or youcan purchase them by mail. If you order a show-erhead directly from a manufacturer, be sure tocontact the manufacturer first—prices and mod-els change.

Installation is usually not difficult for a handyindividual. Unscrew your old showerhead with awrench, smear some pipe goop on the showerarm threads (or use Teflon tape from your localhardware or plumbing-supply store), and screwthe new showerhead into place. (Some shower-heads have a rubber washer, which eliminates theneed for pipe goop or Teflon tape.) You may needtwo wrenches—the second to prevent the showerarm from twisting out of its fitting as you removethe showerhead—and possibly penetrating oil orsome other lubricant to help release the threads.

After removing your old showerhead, youmay find that the shower arm ends in a ball ratherthan in threads. If you can’t unscrew the ball fromthe arm, you will need to install an adapter fromyour local hardware or plumbing-supply storebefore installing the new showerhead. An alter-native is to replace the shower arm with a thread-ed arm from your local supplier—a $3–5 item.Unscrew the arm from the wall and replace itwith a new one. Be sure to use pipe goop orTeflon tape on the threads.

Leaky ToiletsToilets that leak water from the tank into the

bowl waste 5% of all indoor residential water use.

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That number is an estimated national average: ifyou have a leaky toilet, it may be wasting up to50% of your indoor water. It’s worth fixing.

To check for a leak, lift the lid off the tank.

Without disturbing the float or flapper valve, puta few drops of dark food coloring in the tank andwait a few minutes. If the colored water shows upin the bowl, your toilet needs some work.

Take another look in the tank. If water is flow-ing into the overflow tube, the ballcock (the float-controlled valve that lets water into the tank) isn’tclosing properly—it’s either worn out or needsadjustment. Try bending the float arm down. Ifthe ballcock still doesn’t close before water runsdown the tube, it will need replacement.

If the ballcock isn’t the problem, the flappervalve is probably worn out. First check to makesure there is no scale or grit preventing the flap-per from closing properly. If the flapper is in fact

If water is flowing down the overflow tube, try bending thefloat arm (which closes the ballcock) downwards. If thewater level is below the top of the overflow tube but stillruns into the bowl, the flapper valve is probably worn andneeds replacement.

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worn out, replace it with another from a localsupplier, or better yet, replace the toilet with anefficient model.

Buying an Efficient ToiletUnless your house was built in the past few

years under a 3.5-gallon-per-flush building code,it most likely has a toilet which uses 5 or moregallons per flush (gpf). If so, a 1.0–1.6 gpf toiletcan cut your indoor water use by 20–25%, with acorresponding reduction in wastewater flow.Even if you now use 3.5-gallon toilets, you canexpect a reduction of more than 15% in totalindoor water use if you switch to 1.0-gallon toi-lets.

For the average household, switching to effi-cient toilets will save approximately 15,000 gal-lons of water—and $25—annually. If you were toreplace three toilets at a cost of $100 each, the sav-ings would translate into an 8.3% annual rate ofreturn—the toilets would pay for themselves in 81/2 years, and keep on saving year after year. Ifyou can’t afford to replace all your toilets imme-diately, start with the one that is used the most.Your local utility may offer substantial rebates,which would make these toilets an even betterbuy.

For those with overflowing septic system prob-lems, ultra-low-flush toilets may cure the prob-lems for a lot less than the cost of improving theseptic system. A new home with efficient plumb-ing fixtures may realize extra financial savingsfrom a smaller leachfield or lower sewage hook-up fee. Check with your local building inspector.In addition, you will reap the continuing financialbenefits which accrue through reduced water use.

If you’re concerned that an ultra-low-flush toi-let might not do its job properly, remember thatthese toilets are specially designed to operate on

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1.6 gallons or less. Conventional toilets modifiedwith displacement bags, dams, or bricks mayrequire double-flushing, but engineering studiesand our own years of experience show that many1.0–1.6 gpf toilets work as well as or better thantheir conventional counterparts. Rather thansloshing lots of water around in the bowl for along time to little purpose, they use a forcefulpulse of water to complete each flush quickly andcleanly.

Removal of old toilets and installation of newones is easier than it sounds. Before removing atoilet, be sure to turn off the water supply to itand flush all the water out of the cistern. Replacethe wax seal under the base of the toilet with anew one. If you have any doubts about the job, aplumber should be able to do it in a half hour orless. When choosing a toilet, be sure it has thesame rough-in size (distance between the walland the center of the discharge pipe) as your cur-rent toilet. This shouldn’t be a major issue; mostU.S. toilets have a 12” rough-in.

Efficient Faucets Save A LotInexpensive but efficient replacement faucets

can reduce your total indoor residential water useby 3–5%. That may not sound like much, but yourenergy savings through reduced hot-water usewill repay the cost of the faucet in less than a year.In most cases, all that needs to be replaced is thetip of the faucet.

Installation is usually very easy: just unscrewyour old faucet and replace it with an efficientnew one. If it’s corroded and won’t come out eas-ily, a pair of pliers will help.

To determine the right size:• Remove the existing faucet. • If the threads are on the inside, it has

“female” threads. If the threads are on the

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outside, they’re “male.”• If a nickel fits snugly into the threaded end,

it’s a “regular” faucet (15/16” male or55/64” female threads).

• If a nickel doesn’t fit into it but a dime does,it’s a “small” faucet (13/16” male or 3/4”female threads).

• If your faucet is missing from the start, yourbest bet is to choose a regular faucet withdual (both male and female) threads: it willprobably fit.

A bathroom faucet which delivers 0.75–1.5 gal-lons per minute (instead of the usual 2.0–4.0 gpm)will work fine for toothbrushing, washing, or

A water-efficient faucet will pay for itself in less than a year.

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shaving. You’ll need a higher flow in the kitchensink to fill pots and pans: 2.0–2.5 gpm is general-ly plenty. A shutoff lever in the faucet will allowyou to slow the flow temporarily without losingthe temperature setting—a convenient, water-saving feature.

Efficient faucets are widely available throughhardware and plumbing-supply stores. Storesthat sell them often have a display to help youfind the right size. Be sure to determine thedesired flow rate before you buy. If a faucet does-n’t mention flow rate, it probably isn’t an efficientmodel.

Washing MachinesReplacing a typical home washing machine,

which spins on a vertical axis, with a new “hori-zontal-axis” machine can reduce your wash waterneeds by 30–60%. These new efficient washers areavailable in front- and top-loading models. Youwill not only save water, but also detergent andenergy—and your clothes will get cleaner. Anaverage household can save nearly 7,000 gallonsof water a year with such a machine.

If you’re in the market for a new machine, anefficient horizontal-axis model would be a goodinvestment. However, it is probably not cost-effective to replace your conventional machine ifit still has a few years left in it.

Lawn WateringProper watering practices can typically cut

lawn water consumption by 20–50% while main-taining or even improving the health of yourlawn. Most lawns are bluegrass, which, whilebeing a fairly water-demanding species, doesn’tneed watering as frequently as many peoplethink. It grows best when watered evenly, deeply,

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infrequently, and only when it needs it—no moreoften than once every three days in any climate.

You can tell when your lawn needs wateringsimply by walking across it. If the grass springsback up after you lift your foot, it’s not time towater yet; if it stays flat, however, it’s time towater again. When only a few dry spots are pre-sent, watering them by hand can save water andmake the color of your lawn more even.

Water for as long as it takes to irrigate the full4–6-inch root zone—check the depth of wateringperiodically with a screwdriver; in a sufficientlywatered lawn, it should be easy to push in to adepth of about 6 inches. Remember, water deeply,but only when needed. Of course, if it’s raining orhas recently rained, you can reduce the amount ofwater you apply accordingly. Your local waterconservation office may be able to provide infor-mation on lawn watering requirements for yourclimate.

Water in the early morning or in the evening,when wasteful evaporation will generally be low-est. If you live in a humid climate, it’s better towater in the early morning to avoid mold prob-lems.

Use a sprinkler timer, which can irrigate inpulses of 10–20 minutes with 15 or more minutesin between, allowing the water to soak in prop-erly. If the soil doesn’t absorb water as fast as thesprinkler applies it, it will accumulate in puddlesor run off your lawn; both are wasteful and mayharm your lawn (not to mention your driveway,sidewalk, and house). To increase the rate atwhich water is absorbed, you can poke holes inthe soil with an aerator from your local nursery.

If you have an automatic sprinkler system,place empty cans or rain gauges around yourlawn, run the sprinkler for 15–20 minutes, andcheck to see that your sprinkler is distributingwater evenly. You may be surprised to see that

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some parts of your lawn get two to three times asmuch water as other parts. If so, readjust thesprinkler heads and try again. To avoid puddlesor run-off, set your system to run for no morethan 20 minutes at a time. To keep your automat-ic sprinkler operating efficiently, adjust it at leastonce a month during the watering season. Theamount you water in May should be far less thanthe amount you water in July; water only enoughto keep your lawn healthy.

Remaking Your LandscapeEven when it’s watered efficiently, bluegrass

still requires a lot of water. You can remake yourbluegrass lawn into a colorful, durable, drought-resistant landscape and save yourself most of themoney and effort you put into maintaining it.

Regardless of where you live, follow these gen-eral guidelines when remaking your landscape:

• Make sure your soil has plenty of organicmatter to hold water. If it doesn’t, use com-post to improve the soil before you laydown grass. Also use organic matter whenplanting shrubs.

• Keep your lawn small, and put it on a flat,level area where the water won’t run off.

• Circular or rectangular lawns are easiest towater efficiently, without overspray.Narrow strips and odd shapes, especiallywhen they border on driveways, walkways,or buildings, are difficult to water effi-ciently; use wood chips and low-water-useplants and, if necessary, drip irrigation inthose areas.

• Choose a sprinkler pattern that matchesyour lawn.

• Use a drip-irrigation system or “micro-sprinkler” for your shrubs and flower bedsif they require watering. A properly

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designed and installed system can substan-tially reduce both water use and mainte-nance.

• Instead of bluegrass, use a low-water-usegrass or other water-efficient plants. Yourlocal water company or cooperative exten-sion office may be able to provide a list oflow-water-use plants suitable for your area.Remember that the less water your plantsrequire, the smaller will be your weed prob-lem too, and the easier it will be to maintainyour landscape.

Graywater UseIf you’re building a new house or renovating

an existing one and would like to make an extraeffort to improve your water efficiency, you maywish to consider a graywater system.

Graywater is soapy water from bathroomsinks, showers, and washing machines. A gray-water system filters and reuses this wastewater toflush toilets, which obviously don’t need drink-ing-quality water for the job they do. (Graywatersystems normally don’t reuse kitchen sink water

A properly installed drip-irrigation system can reduceboth water use and maintenance.

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because of its high grease and other organic con-tent.) If you install such a system, you might wishto arrange it so you can also use some of the fil-tered water to irrigate your garden. Either way, besure to have your plan approved by your localbuilding inspector or health department.

Except in California, graywater systems arenot yet widely used. While there are a few com-mercially manufactured graywater systems, youcan also assemble one from plumbing parts. Anassembled system including a tank, filters, andpump costs about $600–800. By reusing yourwashwater, a graywater system can reduce yourindoor water use by about 30%, and cut outdoorwater use as well.

Composting ToiletsComposting toilets need no sewer hookup,

septic system, or plumbing. While requiring morespace than conventional toilets, they may be thebest option for certain applications. Like graywa-ter systems, composting toilets can reduce indoorwater consumption by about 30%, and also pro-vide the user with a small amount of high-quali-ty fertilizer once a year.

Rainwater CollectionSystems

Rainwater collection systems, once common inthe United States, can supply a significantamount of water, even in dry regions. Most sys-tems rely on rooftops to collect rain, which is thenstored in barrels or cisterns. Typically they arehomemade using regular gutters and other easilyobtainable parts. Metal or tile collecting surfacesare best, so as to avoid contamination fromasphalt and other roofing materials. The primary

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cost for a system is for storage, which generallyruns 25–75¢ per gallon.

Some rainwater collection systems can be usedin conjunction with graywater systems.Depending on the catchment area, storage capac-ity, and annual rainfall, such a system can meetsome (if not all) of a household’s non-potablewater needs, and in some cases it may providepotable water too.

CongratulationsWhether you’ve refitted your whole house or

just replaced a showerhead, your efforts havesaved you money and made a real contribution tothe cause of improved resource efficiency. Youcan take your success further by promoting effi-cient water use by your local water supplier andlocal and state governments. More information isavailable from the organizations and publicationslisted below.

Additional ResourcesSelected RMI Publications

(When ordering, refer to the publication code in paren-theses; all prices are postpaid in the United States)

The Water Efficiency Revolution. An overview ofhow water efficiency can help the environment,reprinted from Calypso Log Magazine. 2 pp, $1.50.(#W93-5)

Water Efficiency Sampler. Briefly overviews 15 casestudies of projects ranging from hookup fee incentivesto composting toilets. 2 pp, free. (#W92-1)

Graywater Systems, Composting Toilets, andRainwater Collection Systems: A Resource List. Listsdozens of manufacturers and other organizationsinvolved with these technologies, and includes anextensive annotated bibliography. 14 pp, $7. (#W93-18)

Let’s Tap Water Efficiency Before Spending on

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Treatment. Notes that water efficiency is cheaper thannew treatment plants; reprinted from the ChristianScience Monitor. 1 p, $1.50. (#W94-24)

Water Efficiency Publications. A complete list ofmore than two dozen publications related to water use.2 pp, free. (Water pubs list)

Organizations and Publications WhichEncourage Water-Efficient Landscapes

National Wildflower Research Center, 2600 FM 973North, Austin, Texas 78725. Publishes fact sheets,including recommended species lists, source lists, gar-dening and landscaping tips, and bibliographies, avail-able on a state-by-state basis for $2. Members, who con-tribute $25 to the nonprofit center, can receive thesesheets at no charge. Be sure to include a stamped, self-addressed envelope.

The Wildflower Meadow Book: a Gardener’s Guide,by Laura C. Martin, available from Globe Pequot Press,Box Q, Chester, CT 06412 (800/243-0495; in CT,800/962-0973). A thorough description of the design,planting, and maintenance of wildflower meadows ineach of seven regions of the country. Topics coveredinclude naturally occurring plant communities, nox-ious weeds, meadow plants for various purposes, andother useful organizations and books. 300 pp, $16.95,plus $2 postage.

Plants for Dry Climates: How to Select, Grow, andEnjoy, by Rose Duffield and Warren D. Jones, availablein paperback from Price Stern Sloan, Inc., 360 NorthCienega Blvd., Los Angeles, CA 90048. A well-illustrat-ed and colorful manual of plants which do well in aridparts of the country. Topics covered include lawns, gar-dens, annuals, perennials, and planting and plant care.175 pp, $12.95 plus $1 shipping.

Water Wiser: The Water Efficiency Clearinghouse.American Water Works Association (800/559-9855).Provides information on community-wide water-effi-ciency efforts, primarily to water utilities, govern-ments, and community planners.

Energy Efficiency and Renewable EnergyClearinghouse. U.S. Dept. of Energy (800/428-2525).

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Provides information to citizens on a wide range ofissues including energy efficiency, appropriate tech-nologies, and alternative water technologies such ascomposting toilets and graywater systems.

National Drinking Water Clearinghouse. NationalSmall Flows Clearinghouse (800/624-8301). A govern-ment organization that provides information on waterquality issues as well as on technologies suitable forindividual and small-scale water systems, includingartificial wetland water treatment, solar aquatics, andsuccessful water-efficiency programs.

In addition, state and local water conservationoffices and cooperative extension agents may be able tofurnish useful information on water efficiency.

Rocky Mountain Institute1739 Snowmass Creek RoadSnowmass, CO 81654-9199

Tel (303) 927-3851Fax (303) 927-4178

(Note: Our area code changes to 970 after April 2, 1995)

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