Complete a home water audit
Doing a home water use audit can help you understand how you can start saving the most water inside your home. The Portland Water Bureau offers free Home Water Audit Kit to customers. The kit includes instructions for how to do the audit, a bag to measure shower and faucet flow rates, toilet leak detection tablets, and a drip gauge to measure leak rate. An audit may take up to an hour to complete.
Toilet water use
Operating a toilet can cost more money than you might think. A national study by the Water Research Foundation in 2016 found that toilets can account for up to 24 percent of the water used in your home. Whenever a toilet is flushed, there are charges for the water and wastewater related to your toilet’s consumption. While today’s federal requirements specify that new toilets must use no more than 1.6 gallons per flush, there are still many old and inefficient toilets in operation that consume 3.5 or more gallons with each flush. Today, the most efficient toilets use 1.28 gallons per flush or less.
Check your toilet for leaks
Toilet leaks are the most common reason for water use increases. Sometimes it’s easy to tell that your toilet is leaking: you hear running water or a faint hissing or trickling coming from the toilet. But many times, water leaks can be silent, which is why toilet leaks are often overlooked.
Measure how much water your toilet uses
Finding out how much water your toilet uses per flush is a great first step to deciding whether upgrading your toilet is a good investment. Some toilets have labels that say how much water they use per flush. If yours doesn’t have such a label, look inside the tank for a manufacturer’s stamp showing when your toilet was made.
|Manufacture date||Estimated flush volume (gallons per flush)|
|1994 to present||1.0 to 1.6|
|1980 to 1994||3.5 to 4.5|
|1950 to 1980||5.0|
Measure the volume of your toilet tank
If you can’t find the date, or you want to be more exact, use a tape measure to calculate the volume of your toilet tank.
- Remove the toilet tank lid and measure the internal length and width of the tank.
- Measure the depth of the water in the tank. Flush the toilet and measure the depth of the water that remains in the bottom of the tank before it starts to refill (not all tanks will completely empty of water). Subtract the depth of the water that was left in the tank after flushing from the depth of water when the tank was full. This gives you the “net” height of the water.
- Use the calculation below to determine the approximate volume of water used to flush the toilet. Note that you add an additional 0.6 gallons per flush to account for water that is used to refill the bowl.
[Graphic text ID: formula to calculate gallons per flush. Length in inches times width in inches times height of water in inches gives you volume. Divide volume by 231 to get tank volume. Add tank volume to 0.6 (gallons used in bowl) to get final number, total gallons per flush (GPF).]
Replace your toilet
It’s easy to find a water-saving and high-performance toilet thanks to WaterSense, a national program sponsored by the US Environmental Protection Agency. Only toilets that are 20 percent more water efficient than standard toilets and pass rigorous independent performance testing receive the WaterSense label. A new WaterSense high-efficiency toilet could save a family of four over $300 per year on their water and sewer bill. Review the table below to see how much a toilet upgrade could save you per person in your household.
|Toilet flush volume (gallons per flush)||Flushes per person per day1||Gallons used per year||Cost per gallon2||Toilet cost per person per year|
Shower and bath water use
Showers account for about 20 percent of the water used indoors and are typically the third-largest use of water in the average home. According to a national study by the Water Research Foundation in 2016, the average shower uses roughly 17 gallons of water and lasts for around eight minutes. The average bath uses about 30 gallons of water and accounts for roughly 3 percent of the water used indoors. Taking the time to think about how you can conserve water in the shower or bath will help you save water, energy, and money!
Find out how much water your shower uses
The amount of water consumed while taking a shower depends on two main factors: the flow rate of the showerhead and how long the shower lasts.
- Flow rate: Prior to the 1980s, most showerheads used 5 gallons per minute (gpm) or more. By the mid-1990s, federal requirements mandated that new showerheads use no more than 2.5 gpm. Most showerheads are marked with the flow rate on a small silver button in the center of the head. The most efficient showerheads today only use 1.5 gpm.
- Shower length: Changing how long you spend in the shower is the least expensive way to conserve water. A 10-minute shower will use twice as much water as a 5-minute shower taken at the same flow rate. Some people believe that a lower flow rate leads to longer shower times; however, studies show that flow rates have little influence on the duration of the shower.
How much water is used during an eight-minute shower
|Showerhead option||Gallons of water used per minute||Total gallons used per day||Cost per person per year1|
Replace your showerhead
Another great way to conserve water in the shower is to make sure you are using a water-efficient showerhead. Showerheads generally last about 10 years. As showerheads age, they may wear and leak, or the nozzle holes can enlarge or plug, causing them to use more water or change the pattern of the spray so that the shower spray no longer feels even and comfortable. If you have showerheads that are more than 10 years old, it may be time to replace them.
Hot water for showers is also one of the biggest energy users in the home after the furnace. Switching to a water-efficient showerhead not only cuts down on water use, but also the energy needed to make and keep that water hot.
Save water in the bath
The amount of water used while taking a bath varies depending on the size of the bathtub and the level to which the user fills the tub. The standard bathtub size has decreased over time and today the typical modern bathtub holds between 30 to 45 gallons. A person who only fills the tub halfway will consume approximately 30 gallons while bathers that fill the tub up to (or exceeding) the overflow valve may use 40 to 50 gallons.
Follow these helpful hints to use less water in the bath:
- Fill the tub to your belly button. Only fill the bathtub as much as you need.
- Use a small tub insert when possible. Bathing babies, small children, and pets requires much less water, so use a small tub insert or baby bathtub.
- Don’t overfill the tub. Overfilling the tub forces unneeded water into the overflow drain.
Faucet water use
Bathroom and kitchen faucets account for about 19 percent of the water used in the home. In an average home, bathroom faucets run for around eight minutes a day and consume nearly 20 gallons of water per day. Reducing faucet water use and repairing leaks is an easy way to save water and money!
How much water is used at a bathroom sink per day (estimated eight minutes of use per day)
|Faucet option||Gallons of water used per minute||Total gallons used per day||Cost per year1|
How much water is used at a kitchen sink for manual dishwashing (estimated 15 minutes of use per day)
|Faucet option||Gallons of water used per minute||Total gallons used per day||Cost per year1|
Retrofit your faucet
One of the easiest ways to save water with your faucet is to install a water-efficient aerator. Bathroom faucet aerators that flow between 0.5 to 1.0 gpm are generally adequate for hand washing. Kitchen faucets may require a higher flow rate such as 1.5 to 2.0 gpm to fill a sink or spray food off dishes. Reducing the flow can increase the wait time for hot water.
Repair your leaky faucet
Is your faucet dripping? If the answer is yes, you may be wasting a lot of water. A faucet that leaks at one drip per second can waste about eight gallons of water per day, or around 2,900 gallons per year. In some cases, the repair can be relatively simple, such as replacing a worn washer or gasket.
Washing machine water use
About 17 percent of the water used in an average residential home is for washing clothes. Conventional washers built before 2011 typically use about 40 gallons per load. The average four-person household with a standard washing machine can generate more than 300 loads of laundry per year, consuming 12,000 gallons of water. A high-efficiency front-loading washing machine can reduce water consumption by more than half, saving you energy and money. Operating the clothes washing machine with full loads is a great way to reduce water use. Today, the most efficient front-loading washing machines use as little as five gallons of water! Most high-efficiency Energy Star-certified models use closer to 14 gallons per load.
If you are considering the purchase of a high-efficiency washing machine, do your research to find an efficient model that works for you. Visit the Energy Star website to learn more about efficient washing machines
How much water is used by washing machines per day (one load per day)
|Washing machine type||Gallons used per load||Total gallons used per day||Cost per year1|
|Standard||20 to 45||20 to 45||$185.07–$416.40|
Top- versus front-loading washing machines
Top-loading or vertical-axis washing machines are designed to suspend clothes in soapy water while an agitator moves laundry around, dissolving and removing stains and dirt. Design has changed little since they were created in the 1940s, and many top-loading washing machines still use up to 40 gallons per load because they require a large amount of water to keep clothes suspended.
Horizontal-axis or front-loading washing machines use 15 to 30 gallons of water to wash the same amount of clothes as a top-loading machine. A constantly rotating drum lifts clothes in and out of the water to remove dirt and stains, eliminating the need to suspend them in water. Studies have shown that this process is not only gentler on fabric and more water-efficient, but also requires less laundry detergent and saves on the energy used to heat water.
Dishwasher water use
In the debate over using a dishwasher or washing dishes by hand, using an automatic dishwasher to clean dishes generally wins for both water and energy efficiency. Most conventional dishwashers installed in US households today use seven to fourteen gallonsper load and account for less than 2 percent of the water used in an average American home. Despite the small portion of overall water consumption by dishwashers, newer machines are substantially more water-efficient than older models. Today the average machines use a maximum of seven gallons per load—and some use as little as four gallons. Energy savings also result from upgrading to an efficient dishwasher because fewer gallons of water need to be heated per cycle.
To save water, run the dishwasher with full loads only. If you’re handwashing dishes, wash them in a filled sink and let the water run only while rinsing items under the faucet.
The next time you turn on the faucet to pre-rinse your dinner plates, remember that five minutes of pre-rinsing in the sink using running water can use up to 12 gallons of water depending on your faucet. Using the pre-rinse cycle (if your dishwasher has one) to rinse dishes uses approximately one gallon of water.
Another way to prepare dishes for the dishwasher is to do what most appliance manufacturers recommend and scrape (not rinse) dishes before placing them in the dishwasher.
Table of the amount of water used by dishwashers per day (one load per day)
|Dishwasher type||Gallons used per load||Total gallons used per day||Cost per year1|
|Standard||7 to 14||7 to 14||$64.77–$129.55|
Choosing a cycle
Most dishwashers provide a variety of cycle choices. Using the right wash cycle will increase cleaning and water efficiency. Choose the shortest wash cycle for lightly soiled loads and the “heavy” or “pot/pan” cycle for heavily soiled items. Using the heavier setting when it’s not needed won’t clean dishes any better—it will just waste water.
Operate the dishwasher with full loads only. Load dishes properly so that water can reach all dish surfaces. Incorrect loading may cause part of the load or the entire load to be rewashed.
Here are some helpful dishwasher loading tips:
- Face plates toward the center of the dishwasher.
- Put bowls on the top rack facing center so water can reach all surfaces more easily.
- Place large platters and cookie sheets on the bottom rack along the outer edges to prevent them from blocking detergent and water from other dishes.
- Place large serving spoons too big for the silverware basket horizontally across the top rack and face down to not collect water.
- Large pots, serving bowls, and casseroles belong on the bottom rack at a slight angle to ensure proper water contact.
Glasses should go on the top rack between tines, not over them, to prevent them from rattling or coming out with tine marks.