About one home in ten has a leak wasting 90 gallons a day or more. That is not a slow drip under the sink. That is a toilet flapper that stopped seating properly sometime last spring, running into the bowl where nobody looks.
Two tests find most of these. One takes two hours of doing nothing. The other takes ten minutes and a drop of food coloring. Almost nobody runs either.
That gap is the subject here. Water conservation gets discussed as a shopping problem, a matter of picking the right showerhead. The arithmetic says otherwise. EPA’s WaterSense program reports that fixing easily corrected household leaks saves roughly 10 percent on a water bill, and that the average family spends more than $1,000 a year on water. Ten percent of that is about $100 a year for an afternoon of work and a part that costs a few dollars.
One boundary before we start: this is about how much water a household uses and where it goes, not about what is in it. Drinking water quality, filtration and testing are covered elsewhere here.
Where the water goes
Start with the totals, and with a confusion worth clearing up. EPA reports that the average American family uses more than 300 gallons a day at home, and separately, from 2015 US Geological Survey data, that each American uses an average of 82 gallons a day at home. Those are a household figure and a per-person figure, and people mix them constantly. Four people at the national per-person average clear 300 gallons a day easily, which is where the first number comes from.
Roughly 70 percent of that happens indoors. The outdoor 30 percent is a national average that hides enormous variation, and in arid regions it can reach 60 percent.
Indoors, EPA publishes end-use shares across several product pages rather than in one chart, so here they are as the agency states them. Toilets are the largest single use at nearly 30 percent of indoor consumption. Showering is next at nearly 17 percent, almost 40 gallons a day for the average family and nearly 1.2 trillion gallons a year nationally. Faucets and clothes washers make up most of the rest. USGS, from a different base, puts typical indoor use at 80 to 100 gallons per person per day and ranks the order the same way: toilet flushing first, then showers and baths.
Clothes washers are easy to underestimate because the per-load number looks small. ENERGY STAR reports that the average family runs about 300 loads a year, that a standard full-size machine uses about 20 gallons a load against about 14 for a certified model, and that heating water is roughly 90 percent of a washer’s energy use. Three hundred loads at 20 gallons is 6,000 gallons a year from one appliance.
One piece of scale belongs alongside all of this. USGS estimated total US withdrawals at about 322 billion gallons a day in 2015, and public supply, the systems that serve homes, accounts for about 14 percent of withdrawals while serving roughly 87 percent of the population. Household use is a modest slice of the national total. That is a reason to understand the system rather than a reason to shrug, and it is why the strongest arguments for household efficiency are the local ones: your bill, your utility’s capacity, and the state of your own aquifer or reservoir.
Leaks are the cheapest win, and two tests find them
Most advice has this backwards. An efficient fixture saves water every time you use it, which is real but gradual. A running toilet wastes water every minute of every day whether anyone is home or not. The fixture is the slow lever. The leak is the fast one, and it goes unchecked in most houses.
EPA’s WaterSense figures put numbers on it. The average household’s leaks waste nearly 10,000 gallons a year on one EPA page and 9,400 on another, which that page expresses as about 180 gallons a week. Nationally it has published figures of nearly 900 billion gallons and, on an earlier version of the same page, nearly 1 trillion gallons a year. Read those as one rounded estimate at two vintages, not as a trend.
The component numbers are more useful than the national ones. A faucet dripping once a second wastes more than 3,000 gallons a year. A showerhead leaking ten drips a minute wastes more than 500. An irrigation line with a hole a thirty-second of an inch across loses roughly 6,300 gallons a month. And a toilet flapper, the rubber seal at the bottom of the tank, should be checked periodically and replaced at least every five years, because a worn one leaks silently into the bowl.
The meter test. Find your water meter, write down the reading, then use no water at all for two hours. No ice maker, no irrigation timer, no one running a tap. Read the meter again. If the number moved, something in your system is using water when nothing should be.
The toilet dye test. Put a drop of food coloring in the tank, not the bowl, and wait ten minutes without flushing. If color shows up in the bowl, the flapper is leaking. Flush afterward so the dye does not stain the tank.
The winter bill check. EPA offers a rough threshold: a family of four using more than 12,000 gallons in a cold month such as January or February probably has serious leaks, because outdoor use is close to zero then.
A leak you cannot locate is the point to stop guessing. Water appearing on the outside of a pipe, a stain spreading on a ceiling, a warm spot on a slab floor, or a bill that jumps with no change in habits all point to something behind a wall or under concrete. That is a job for a plumber with acoustic or thermal leak detection, not for another weekend of looking.
What the WaterSense label certifies
Environmental labels fall into categories, and this one sits in a specific and often misread place. WaterSense is not a law, and it is not a private eco-label invented by an industry group. It is a government certification program run by EPA, which writes the specifications, with independent third-party organizations doing the verification, testing and periodic market surveillance.
The efficiency threshold is the part everyone knows: a labeled product must be at least 20 percent more water efficient than average products in its category. The performance half is the part that gets skipped, and it is the more interesting half. EPA’s own language is blunt about why: the agency states that “equal or superior product performance is a vital component of the WaterSense label.”
Those criteria are specific rather than aspirational. Labeled showerheads are independently certified against three tests developed with the ASME and CSA joint harmonization group: spray force sufficient for user satisfaction, spray coverage that distributes water across the bather rather than too narrowly or too widely, and pressure compensation so flow holds up across the range of household water pressures. Labeled bathroom faucets are certified for life cycle, for being lead-free where they dispense drinking water, and for adequate flow at low pressure.
The program extends past individual products. A WaterSense labeled home must be independently certified as at least 30 percent more water efficient than typical new construction and free of wasteful leaks. EPA also labels certification programs for landscape irrigation professionals, which is a certification of a certification rather than of a product.
Fixtures, and the one that gets returned
With the label understood, the fixture numbers are easy to read.
Toilets. An inefficient older model can use as much as 6 gallons a flush. The current federal standard is 1.6 gallons. A WaterSense labeled toilet uses 1.28 gallons or less, which is 20 percent below the federal standard. EPA puts household savings at nearly 13,000 gallons and more than $170 a year, or about $3,400 over the fixtures’ lifetime.
Showerheads. Standard models run at 2.5 gallons a minute. Labeled ones use no more than 2.0. EPA estimates the average family saves about 2,700 gallons and more than 330 kilowatt-hours a year, the second number because most shower water has been heated.
Bathroom faucets. Standard flow is 2.2 gallons a minute and the current WaterSense maximum is 1.5, a reduction of 30 percent or more, saving an average family about 700 gallons a year. EPA drafted a stricter 1.2 gallon version of the specification and has paused that work, so 1.5 is what the label means today.
Now the honest part. A showerhead that someone in the house hates gets unscrewed and replaced with whatever feels better, and the savings go with it. This is not a character failing, and it is precisely why the spray force and coverage tests exist. If you are choosing a fixture, the specification is the floor and your household’s tolerance is the ceiling, and a 2.0 gallon head that everyone is happy with beats a 1.5 gallon head in a box in the garage.
Outdoors, where the big numbers live
For much of the country the largest household water decision is made in the yard. EPA reports that residential outdoor use runs to nearly 8 billion gallons a day nationally, mostly landscape irrigation, and that the average US household uses more water outdoors than for showering and clothes washing combined.
It is also the least efficient water in the system. Up to half of outdoor water can be lost to wind, evaporation and runoff, and EPA puts the waste from a poorly maintained automatic system at up to 25,000 gallons a year. For a sense of scale, watering a typical lawn 20 minutes a day for a week uses about as much water as running a shower nonstop for four days.
Four practices do most of the work, and none of them requires new equipment.
Timing. Do not water in the middle of the day, when the sun takes a large share of it before plants can use it.
Amount. Most landscapes need roughly one inch of water a week including rainfall. EPA’s own method for finding out how long that takes is a tuna can: set empty cans around the lawn, run the sprinklers, and time how long they take to fill to half an inch. Water for that long twice a week, then adjust for weather and for how the plants respond.
Soil. On clay or on a slope, water pools instead of soaking in. Splitting a cycle into shorter runs with pauses between them, which EPA calls cycle and soak, fixes most of that. Compacted soil benefits from aeration. A soil test through a cooperative extension office or state university tells you what you are working with, including pH and organic matter.
Mulch and plant choice. EPA recommends mulching to a depth of three to four inches, keeping a few inches clear around trunks so the bark does not rot. Regionally appropriate and native plants, once established, need little beyond normal rainfall. Group plants with similar water needs into the same irrigation zone, and keep turf where it serves a purpose such as a play area rather than as a default ground cover.
If you do have an in-ground system, EPA reports that a WaterSense labeled irrigation controller, which adjusts to weather or soil moisture, can cut irrigation use by up to 30 percent and up to 15,000 gallons a year, and that working with a WaterSense certified irrigation professional reduces a household’s irrigation use by about 15 percent, roughly 7,600 gallons.
Scarcity is local, so priorities are too
National averages mislead here more than almost anywhere else. In May 2014 the Government Accountability Office surveyed all 50 state water managers and got a response from every one. Its finding: “40 of 50 state water managers expected shortages in some portion of their states” over the following decade under average conditions.
Note the wording. Some portion of their states. Water scarcity is a watershed-level and sometimes a neighborhood-level fact, not a national one, and the right priorities differ accordingly.
In a Phoenix-style arid metro where outdoor use can approach 60 percent of household consumption, irrigation scheduling, soil, mulch and plant choice are where the large gallons are. Indoor fixtures are a rounding error by comparison. In a Pittsburgh-style humid city with ample supply, outdoor irrigation may be occasional, and the better arguments for efficiency are the bill, the energy burned heating water, and the load on treatment and sewer capacity rather than the raw gallon.
Two local facts are worth looking up and neither is hard to find: whether your utility has a published drought stage or watering restrictions in effect, and how your water and sewer charges are structured. Both are specific to your system, and both tell you more than any national figure in this article.
Greywater and rainwater, where the law decides first
Reusing the water from a shower or a washing machine, or catching rain off a roof, is where household water conservation stops being a personal decision and becomes a legal one. EPA’s own landscaping guidance makes the point in passing, advising that rain barrels and cisterns can supplement irrigation but that you should check your state’s rules first.
That variation is documented rather than rumored. EPA maintains a tool called the Regulations and End-Use Specifications Explorer, which presents state laws and policies governing water reuse, with a map of which states have adopted reuse guidelines or regulations and which have authorizing laws but no standards. It sorts reuse by source, including treated municipal wastewater, onsite collected waters with greywater among them, stormwater and rainwater collected on site, and by end use, from landscape irrigation to agriculture to potable reuse. EPA notes that its summaries are not legally binding and that where one conflicts with the law, the law governs.
On the health side, the research is clearer than the law. A 2018 quantitative microbial risk assessment in Science of the Total Environment modeled household greywater from bathroom, laundry and kitchen sources and concluded that all three could be used safely for toilet flushing after simple microfiltration, while kitchen greywater did not meet the benchmarks for irrigating food crops. A 2014 study in the same journal, sampling 34 Israeli households, found that the treatment system was the variable that mattered: professionally designed treatment produced acceptable risk across the scenarios tested, and inadequately treated greywater did not.
Behavior is the gap. A 2012 study in Water Research reported that more than a quarter of greywater users in Melbourne, Australia were irrigating vegetable gardens with it, against their own government’s advice, and found that bathroom water carried a lower modeled disease burden than laundry water.
Roof-harvested rainwater shows a similar split. A 2017 study in Environmental Science and Pollution Research sampled rainwater tanks in American Samoa, found Cryptosporidium in 86 percent of them, and ranked illness risk as lowest for chlorinated tap and well water, higher for tank rainwater and highest for untreated stream water, recommending treatment before use. A 2026 study in the Journal of Environmental Management sampled 100 domestic tanks around Adelaide, Australia, where 67 percent of surveyed households drank from them, and detected Campylobacter jejuni in 13 percent, Pseudomonas aeruginosa in 12 percent and Salmonella in 10 percent.
None of these are US regulatory findings and most are not US sites, so read them as what they are: consistent evidence that captured water is not clean water. For irrigating ornamental plants the risk picture is manageable. For food crops eaten raw, and certainly for drinking, it is a different question and a treatment question.
Two situations call for professional input rather than a judgment call. If anyone in the household is pregnant, on chemotherapy or immunosuppressants, or otherwise immunocompromised, raise greywater or tank water with their clinician before putting it near food crops. And no alternative supply should be plumbed into a house without a licensed plumber, because an improper connection between a non-potable line and the drinking water system is the specific failure that contaminates everything downstream of it.
Start here, this week
The order of operations is not intuitive, so here it is directly.
- Run the two-hour meter test. It costs nothing and it is the only check that finds leaks you have no symptoms for.
- Dye-test every toilet in the house. Ten minutes each, and a flapper is a cheap part.
- Pull your last four water bills and look at a cold-weather month. If a household of four cleared 12,000 gallons with the sprinklers off, keep looking.
- If you have an irrigation timer, go find out what it is set to. Most households inherited that schedule and left it alone.
- Only then think about fixtures, and when you do, read both halves of the label.
The toilet is the fixture to watch. It is the largest indoor use in a normal house and the most common place a silent leak hides, which means the same fixture is both the biggest thing you can improve on purpose and the biggest thing that can go wrong without telling you.
Keep exploring: park access, personal care product footprint and CITES.
Sources
- U.S. Environmental Protection Agency. “WaterSense: Statistics and Facts.” epa.gov
- U.S. Environmental Protection Agency. “WaterSense: How We Use Water (January 19, 2025 web snapshot).” 19january2025snapshot.epa.gov
- U.S. Environmental Protection Agency. “WaterSense: Fix a Leak Week (January 19, 2025 web snapshot).” 19january2025snapshot.epa.gov
- U.S. Environmental Protection Agency. “WaterSense: The WaterSense Label.” epa.gov
- U.S. Environmental Protection Agency. “WaterSense: Residential Toilets.” epa.gov
- U.S. Environmental Protection Agency. “WaterSense: Showerheads.” epa.gov
- U.S. Environmental Protection Agency. “WaterSense: Bathroom Faucets.” epa.gov
- U.S. Environmental Protection Agency. “WaterSense: Outdoors.” epa.gov
- U.S. Environmental Protection Agency. “WaterSense: Watering Tips.” epa.gov
- U.S. Environmental Protection Agency. “WaterSense: Landscaping Tips.” epa.gov
- U.S. Environmental Protection Agency. “Regulations and End-Use Specifications Explorer (REUSExplorer).” epa.gov
- U.S. Government Accountability Office. “Freshwater: Supply Concerns Continue, and Uncertainties Complicate Planning (GAO-14-430, May 2014).” gao.gov
- U.S. Geological Survey. “Water Use in the United States.” usgs.gov
- U.S. Geological Survey. “Domestic Water Use.” usgs.gov
- U.S. Geological Survey Water Science School. “Water Q&A: How much water do I use at home each day?.” usgs.gov
- ENERGY STAR (U.S. Environmental Protection Agency). “Clothes Washers.” energystar.gov
- PubMed. “Shi KW, Wang CW, Jiang SC. “Quantitative microbial risk assessment of Greywater on-site reuse.” Science of the Total Environment, 2018. PubMed. DOI: 10.1016/j.scitotenv.2018.04.197.” doi.org
- PubMed. “Maimon A, Friedler E, Gross A. “Parameters affecting greywater quality and its safety for reuse.” Science of the Total Environment, 2014. PubMed. DOI: 10.1016/j.scitotenv.2014.03.133.” doi.org
- PubMed. “Barker SF, et al. “A probabilistic model of norovirus disease burden associated with greywater irrigation of home-produced lettuce in Melbourne, Australia.” Water Research, 2012. PubMed. DOI: 10.1016/j.watres.2012.12.012.” doi.org
- PubMed. “Kirs M, et al. “Rainwater harvesting in American Samoa: current practices and indicative health risks.” Environmental Science and Pollution Research, 2017. PubMed. DOI: 10.1007/s11356-017-8858-z.” doi.org
- PubMed. “Cooper-Beknazarova M, et al. “From roof to tap: Emerging public health risks in harvested rainwater.” Journal of Environmental Management, 2026. PubMed. DOI: 10.1016/j.jenvman.2026.130884.” doi.org