Water Conservation

Possible Causes of Excess Usage

There are many reasons that a customer may generate an irregularly high bill.  The average range for single-family homeowner usage is 2,000 to 20,000 gallons per month, without lawn irrigation.  Below are some reasons that may cause your water usage may be unusually high.

  • Toilet tank flapper valves frequently fail to close properly, due to age or poor quality.  A symptom is a tank that never stops filling after a flush or will stop for a short time and then start filling again.Additionally, older toilets can use 3.5-8 gallons per flush (gpf). Newer toilets only use about 1 gpf. A new toilet alone can reduce your water usage by up to 75 percent.  Possible excess usage = 5,000 gallons per day.
  • Older shower head fixtures tend to use as much as 10 gallons per minute versus something more modern which only uses 2-3 gallons per minute. Water conservation in the shower is also helpful because it reduces the work of your water heater.
  • Clothes washers alone can account for 20% of household water usage. Modern, high-efficiency washers use about half the water as older washers.
  • Dishwashers typically only use 1-2% of household usage, but newer, high-efficiency models can reduce that by half.  By the way, washing dishes in the dishwasher is more efficient than hand washing them in the sink.
  • Spigots on the outside of your home turned on, or left open by intention, error or vandalism.  Possible excess usage = 10,000 gallons per day.
  • A pipe break or leak on the customer’s side of the meter.  Excess usage depends on the pipe size.  Possible excess usage = 100 to 200,000 gallons per day.
  • Lawn irrigation systems left on, depending on the meter size and number of heads. Broken sprinkler heads reduce your irrigation system’s resistance to flow, which means your usage will increase even though the time the sprinkler is on remains the same.  Possible excess usage = 500 to 2,500 gallons per day.
  • Household guests can use approximately 200 gallons per person per day.
  • Filling a pool can use approximately 8,000 to 30,000 gallons.

Water-Wise Lawn Watering

How Much Water Does Your Lawn Need?  For lawns, water deeply but infrequently to encourage deep roots.  The key to watering your grass is to apply enough water to soak down to the depth of the roots.  The amount varies with soil type, but a good guide is to apply no more than one inch of water every time, which is enough to soak the soil to between six and 10 inches.

Measure Your Sprinkler Output.  Without knowing it, you could easily drop up to 300 gallons of water in one hour and end up over-watering your lawn.  Here’s how to test your sprinkler output so you can adjust your watering time:

  • Place six to eight shallow, flat-bottomed cans at scattered locations around your lawn. Tuna or cat food cans work well.
  • Run your sprinklers for 15 minutes.
  • Use a ruler to measure the depth of water in each can. Add all the numbers, and then divide by the number of cans to find the average output.
  • This average number is your sprinkler output number.  It is the average amount of water your sprinklers apply in 15 minutes.
How long and how often should your water? After you’ve calculated your sprinkler number in the previous step, you can calculate how long to run your sprinklers. Simply locate your sprinkler number in the chart below, and then find the corresponding watering time.

Sprinkler Number

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Watering Time (minutes)

75

50

37

30

25

22

19

16

15


Now put your numbers to work. Set your sprinkler timer and water your lawn for the correct number of minutes.  Wait one hour, and then push a spade or long screwdriver into the ground to see if you’ve soaked the soil to the appropriate depth.  It will slide easily through wet soil but will be difficult or impossible to push through dry soil.

  • By the way, if you run your sprinklers for the correct number of minutes, but water pools off your lawn, then you need to split your watering time into two or more sessions.  Wait an hour between sessions for the water to soak in.
  • Water only when your turf is stressed from lack of water.  How can you tell?  Step on it.  If you leave distinct footprints or the grass doesn’t spring back, it’s time to water.  As long as your apply one inch of water (including any rainfall) each time you water, then no more than once a week is typically enough to keep your lawn green throughout the summer.

Morning is the best time to water because watering in the evening can invite fungus to grow on your plants at night.

*   Put a rain gauge in your yard.  If you get ¾ to 1 inch of rain in a week, you can skip your next lawn watering.

*   If you have an automatic sprinkler system, attach a rain-sensor or moisture-sensor shutoff device.

*   Use a rain barrel to collect rainfall and runoff from downspouts.  Use the rainwater to water container plants and gardens.  Make sure your rain barrel has a good, well-fitted screen so it will not harbor mosquito larvae.

Additional Resources


Indoor Water Use in the United States (PDF)
NRCS Lawn Irrigation Guide (PDF)