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Using Less Water Doesn’t Just Save Water, It Saves Energy!

19 October 2011

 

Did you know that you save energy by using less water, even if that water is cold?  Consider this statistic: “four percent of the nation’s electricity use goes towards moving and treating water and wastewater.”  That may sound ridiculous but think of it this way- water is heavy at 8.34 pounds/gallon, and it takes energy to move or pressurize water.  From moving water from the source, treating it, distributing it to our homes and our fixtures, and finally wastewater treatment, every step involves using energy.  Now, the energy used at each step can vary considerably depending on your local water utility system. Most utilities are in the range of 1250 Kilowatt hour (kWh)/million gallons (MG) to 6,500 kWh/MG.

Range of energy used at each step(source):

Water Use Cycle Segments Range of Energy Intensity (kWh/MG)
Low High
Water Supply and Conveyance 0 14,000
Water Treatment 100 16,000
Water Distribution 250 1,200
Wastewater Collection & Treatment 700 4,600

 

When it comes to energy, the source of our water matters.  If your water comes from surface water such as lakes and rivers, there can be little to no energy use by utilizing gravity to move the water to a treatment plant.  Groundwater, however, does take energy to get the water out of the ground, approximately 2,000 KWh/MG.  Here in Minnesota, our drinking water comes from a combination of surface water and groundwater. Groundwater is the main source for Minnesota, serving about 70% of households.  Surface water comes mostly from the Mississippi and serves cities such as Minneapolis, Golden Valley, New Hope, Columbia Heights, Maplewood, Saint Paul, West Saint Paul, Mendota Heights and St. Cloud. Duluth gets its water from Lake Superior. (Source)

EXCITING CONCLUSION:  Saving water in our homes saves energy because it lessens the amount of water distributed and amount of wastewater to be treated. One statistic from the EPA estimates that if just 1% of the American population switched to WaterSence labeled toilets, that it would save enough energy to power more than 43,00 houses with electricity for a month!  There are many easy ways to reduce water waste in your home, like installing high efficiency water fixtures and taking five minute showers.  It will make a difference!

3 Comments leave one →
  1. 19 October 2011 1:52 pm

    Any idea what the average residential water use is in Minnesota, either per person or per household? We’ve made pretty good strides on reducing water use with dual-flush adapters, an HE clothes washer, lower-flow fittings, and a rain barrel. We’re down to about 25 gallons per person per day, which still sounds surprisingly high!

    • 21 October 2011 9:38 am

      According to the Minnesota Department of Natural Resources, the average water use in the Twin Cities Metro Area is 75/gallons per person per day! So while 25g/d/p might seem high, you are definitely doing a great job conserving.

      • 25 October 2011 11:54 am

        Thanks for looking that up! As the kids turn into teenagers, we’ll see how that number changes. 😉

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