Have you ever wondered how much it costs to flush your toilet or take a shower? About 85% of the U.S. population uses public water and 80% uses public sewer. That means you’re paying every time you use water, either directly to the government or utility companies as a homeowner or as part of your rent. And these costs can add up quickly. Not only do you have to pay to flush the toilet, wash your hands, take a shower or bath, and wash your clothes and dishes, you also have to pay to water your grass or garden or potentially fill your pool. This can be particularly expensive if you live in an arid environment (where a pool might be especially enticing). So how much does this all cost on average?
How Is Water And Sewer Use Measured?
Water and sewer use is typically measured by the number of gallons that pass through a meter into your home. This meter may be located outside your house by the curb or inside your house in the basement, particularly in colder climates. You can read more about how to find your water meter here. My water meter is in my basement behind a panel, as you can see below:
Your utility company or public works department typically uses automatic meter reading to record your current meter data several times a year (usually once per quarter). You’ll notice in the above picture there is a device with a cord labeled ECR. This stands for electronic communications register and is connected to a device on the outside of the home which a worker will scan to record the water meter reading without having to enter the house. The previous reading is subtracted from this reading to determine the number of gallons your household used during the period.
Sewer use is often a bit more complicated to measure. While some localities do use sewer meters, many charge only based on the water flow into your home. But not all water that flows into your home flows out through your sewage. Any water used for gardening or landscaping, for instance, does not go down the drain. To account for this, some places in cooler climates calculate sewer usage in the winter months (when people are not watering their yards), and charge for that same usage for the rest of the year because they assume excess usage is not from water use inside the home.
How Is Water And Sewer Use Charged?
Water and sewer use are generally charged based on the number of gallons used during a period, with the exception of flat flee rates, which are the same regardless of gallons used but are a less common fee structure. Typical fee structures include uniform rates (price/gallon), increasing block rates (higher price for higher usage), declining block rates (lower price for higher usage), seasonal rates (higher rates in months with higher demand), drought rates (higher prices with increasing drought levels), and water budget based rates (higher rates for exceeding anticipated needs).
In my area, we have a flat fee at low water usage, followed by increasing block rates. Here are the rate tables for water and sewer usage:
| Water | Sewer | ||
| Gallons | Cost | Gallons | Cost |
| 0-5,000 | $45.80 flat fee | 0-10,000 | $16.25 + $10.99/thousand |
| 5,001-20,000 | $5.53/thousand | 10,0001-30000 | $11.61/thousand |
| 20,001-40,000 | $7.88/thousand | 30,001+ | $12.35/thousand |
| 40,001-100,000 | $8.40/thousand | ||
| 100,001-250,000 | $9.01/thousand | ||
| 250,001-500,000 | $9.46/thousand | ||
| 500,001-1,000,000 | $9.90/thousand | ||
| $1,000,001+ | $10.61/thousand |
You may also be charged miscellaneous fees on top of the water usage fees. For instance, my sewer bill also includes a $15 Bay Restoration Fee.
What Is The Average Cost to Use Water For Various Functions?
To determine the average cost of using water for various activities, we first have to determine average water usage and rates. This is surprisingly difficult. Estimates range from 82 gallons per person per day (which would be 205 gallons for an average household) to more than 300 gallons per household per day. I chose to go with 275.7 gallons per household per day, 137.7 gallons of which are used inside. This is data from a 2016 Water Research Foundation study, which includes both U.S. and Canadian households but falls between the other estimates so seems reasonable.
For rates, I used data from Move.org, which found that the average household spends $45.44 per month for water and $66.20 per month for sewer. For a 1-month total of 8,271 gallons of water usage and 4,131 gallons of sewer usage based on the above averages, this comes to rates of $0.0055/gallon of water usage and $0.016/gallon of sewer usage.
The next step was to determine the number of gallons used for each activity. This data comes primarily from the Water Research Foundation study mentioned above and described in detail on Wikipedia. This information was then multiplied by the average rates to determine the cost for each water use, as you can see in the table below:
| Water Usage | Gallons | Water Cost | Sewer Cost | Total Cost |
|---|---|---|---|---|
| Flush Toilet | 2.6 | $0.01 | $0.04 | $0.05 |
| Shower | 15.8 | $0.09 | $0.25 | $0.34 |
| Bath | 20.2 | $0.11 | $0.32 | $0.43 |
| Run Faucet | 0.5 | $0.00 | $0.01 | $0.01 |
| Wash Clothes | 29.3 | $0.16 | $0.47 | $0.63 |
| Wash Dishes | 6.1 | $0.03 | $0.10 | $0.13 |
| Use Sprinkler (1 h) | 1,020 | $5.60 | – | $5.60 |
| Fill Kiddie Pool | 25.8 | $0.14 | – | $0.14 |
| Fill Inflatable Pool | 272 | $1.49 | – | $1.49 |
| Fill Above Ground Pool | 13,500 | $74.17 | – | $74.17 |
| Fill Inground Pool | 17,280 | $94.93 | – | $94.93 |
Flushing the Toilet
Surprisingly, toilet flushing makes up the highest use of water in the average home and makes up about 24% of total indoor water consumption. On average, a person flushes the toilet 5 times a day, and the average flushing volume is 2.6 gallons per flush (gpf). This comes to $0.05 per flush. However, low-flush toilets use 1.6 gpf and high efficiency toilets only use 1.28 gpf, so your average cost per flush may be lower.
Showering
The average shower (7.7 minutes with an average flow rate of 2.1 gallons per minute) uses 15.8 gallons of water and is the second largest use of water in the home. This comes to $0.34 per shower. You can reduce the cost of showering by shortening your shower, turning off the water while lathering, or by using a low-flow showerhead.
Bathing
Though only 47% of the sampled households took baths, they still use a significant amount of water and are commonly used for small children. The average bath uses 20.2 gallons of water, which comes to $0.43.
Running the Faucet
Running the faucet for various uses including washing your hands, cleaning, brushing your teeth, filling glasses, etc. makes up 19% of overall indoor water use, but each time the faucet is run, it only uses 0.5 gallons on average (running for 30 seconds at a flow rate of 1 gallon per minute). This comes to just $0.01 per use, but clearly the cost adds up over time. You can reduce wasted water by turning off the tap while lathering your hands or brushing your teeth.
Washing Clothes
Washing machines make up 17% of indoor water use, as the average family washes 5.4 loads of laundry each week. Each load uses 29.3 gallons of water on average, which comes to $0.63. You can save money by purchasing an Energy Star certified clothes washer, which should use only 15 gallons of water per load.
Washing Dishes
Dishwashers only make up about 1% of total indoor water use. The average family washes about 1.8 loads per week, and each load uses 6.1 gallons, which comes to $0.13. You can reduce this cost by purchasing an Energy Star dishwasher, which uses between 2.4 and 3.2 gallons per load.
Watering the Yard/Garden
Outdoor watering costs depend on how much water is used. Using a sprinkler to water for 1 hour with a standard 5/8 inch hose uses 1,020 gallons and thus costs $5.60. For other hose sizes or an irrigation system, see here for gallon estimates. To avoid wasting water, try to only water either first thing in the morning or in the late afternoon. This could save you a significant amount of money over the long run.
Filling a Pool
There’s nothing quite as relaxing as soaking in a pool on a hot day, and kids love to splash in the water. The cost to fill your pool depends on its size. A kiddie pool is small at about 25.8 gallons and so costs only $0.14 to fill. A larger inflatable pool may be 272 gallons (we used one this size last summer), which costs $1.49 to fill. Above ground and inground pools are significantly larger. An average above ground pool is 13,500 gallons, which costs $74.17 to fill, and an average inground pool is 17,280 gallons, which costs $94.93 to fill.
Conclusion
You’ll notice that the average sewer rate is about 3 times the average water rate. This is due to the costs of wastewater treatment. For those whose sewer bills are determined based on winter usage, try to keep your water usage especially low during those months to save big.
Overall, water and sewer costs are low on a per gallon basis, but we use thousands of gallons per month. The average cost to flush a toilet is just $0.05 for 2.6 gallons, but we flush an average of 991 gallons per month, which comes to $21.33 for both water and sewer. That’s about 381 flushes per month! Try to cut back on water usage just a little bit each day and you could end up saving quite a bit on your next water and sewer bill.
Cozy Nest Egg 