Water Resources for Walla Walla

By Blythe Mackey


(Photo courtesy of Washington State Department of Health)



              Of all the water on the Earth, only three percent is fresh water.  Within this fresh water supply, less than one third of one percent is available to humans.  The remaining fresh water is frozen in glaciers, in polar ice caps, or deep within the earth.  Because fresh water is a precious natural resource, necessary to sustain all life on Earth, it is important that we are aware of where our water resources come from, how they are used, and what we can do to conserve them.    

Where does our water come from?  

(Map courtesy of the Walla Walla Basin Watershed Council)

            Drinking water around the world is taken from surface and groundwater sources.  Surface water sources include lakes, rivers, streams and springs.  Groundwater sources are aquifers and accessed by wells.  The City of Walla Walla uses a combination of surface and groundwater sources to supply water.  In 2000, Mill Creek provided 85.9 percent of the water supply, and seven wells throughout the city provided the remaining 14.1 percent.   
Surface water from Mill Creek is collected at an intake facility in the Mill Creek Watershed, straddling the Oregon-Washington border.  The headwaters area (36 square miles) of the Mill Creek watershed is carefully protected and managed to prevent contamination of the water.  This water is then piped approximately 36 miles to the Mill Creek Water Treatment Plant, where it is collected in two 7.5 million-gallon open reservoirs to allow sediment to settle.  The water is then treated with ozone, a strong oxidant, in order to destroy bacteria, microorganisms, and organic materials that may be present in the water.  After ozonation, the ozone is removed from the water and a specific amount of chlorine is added to the water to protect against re-growth or contamination within the distribution system.  Water quality tests are performed daily to ensure maximum water quality.  In 2000, no contaminants were detected, nor were Cryptosporidium or Giardia found in the water supply.
Radiocarbon dating at the wells indicates that the well water is over 20,000 years old.  Ground water from deep within the basalt aquifer is not treated because the water is considered free of any biological contaminants.    

  (Diagram courtesy of the Mill Creek Treatment Facility)




(Information and figures from the City of Walla Walla 2000 Water Quality Report)


How do we pay for our water use?

              Water rates are based on “ready-to-serve” and “consumptive use.”  The ready-to-serve, a monthly charge based on meter size regardless of water use, helps to cover the costs of providing water distribution facilities, infrastructure, and staff.  The consumptive use is charge based on the amount of water used and is monitored by a water meter.  
                                                                                 (Information from the City of Walla Walla Water Division Webpage)


What is a water right?

            A water right is the legal authorization to use a certain amount of public water for specific beneficial purposes.  This right must be applied for and approved before water use begins. 
A water right is needed when whenever you divert surface water, including water contained in lakes, rivers, streams, and springs.  It is also needed if you divert more than 5,000 gallons per day of groundwater or irrigate more than a half acre of land. 
A water right is not needed if you use less than 5,000 gallons per day of groundwater from a well for the following uses: 

-  stock watering 
-  single or group domestic purposes 
-  industrial processes 
-  watering less than a half acre of noncommercial lawn or garden 
The criteria for assessing applications for water rights includes: 
-  beneficial use 
-  no impairment of existing (senior) water rights 
-  water availability 
-  no detriment to public  

(Information from the Washington State Water Law A Primer, Publication #WR-98-152, Washington State Department of Ecology)

              The city of Walla Walla holds the senior water right, which was issued in 1866, for Mill Creek in Oregon.  This allows for the diversion of 28 cubic feet per second (cfs).  An additional water right is currently being determined to allow for the withdrawal of 20 cfs of Washington water during the winter when stream flows are higher.  This water would be used in the Aquifer Storage and Recovery System (ASR).  
                                                                         (Information from the City of Walla Walla 2000 Water Quality Report)


What is the Aquifer Storage and Recovery System (ASR)?  

            The ASR was established in 1999, in response to concerns about the aquifer level falling as much as four feet per year.  The system is designed to store excess winter water to be utilized later, during high-consumption and low-surface flow periods.  Currently, the ASR consists of one well located at the Mill Creek Water Treatment Plant that is recharged with treated water when surface water supply exceeds water demands.  The treated water is “pumped” into the well by gravity flow at 1250 gallons per minute.  
                                                                         (Information from the City of Walla Walla 2000 Water Quality Report)


Where does our water go after we use it?

Wastewater is treated at the City of Walla Walla Wastewater Treatment Facility.






Water Conservation Tips

            Water is our most precious resource.  It is used daily to sustain life on earth, within our communities and environment.  For this reason, it is important to protect our water resources for future generations by conserving the amount of water we use.   


1. Check toilets for leaks.  Drop food coloring or a leak-detection tablet in the tank.  If color appears in the bowl, there is a leak requiring immediate attention.

2. Flush only when necessary.  Every time you flush you use about six gallons of water.  Don’t use the toilet as a wastebasket.

 3. Reduce the water level per flush by installing a water-displacement device in the toilet tank.  A plastic bottle, weighted with water or sand, works well.  Never use a brick.

4. Take shorter showers.  Turn off water flow when lathering up and turn it back on to rinse.

5. Install water-saving showerheads or flow restrictions, which are available at local hardware stores and other retail outlets.

6. Take baths.  Only the shortest shower saves more water than a partially-filled tub.  Also, consider bathing small children together.

7. Turn off the water after wetting your toothbrush.  Use a glass of water to rinse.  Avoid letting the faucet run.

8. Rinse your razor in a sink of water.  Letting the water run uses about three gallons per minute.

9. Check faucets and pipes for leaks.  A small drip from a worn washer can waste 20 or more gallons per minute.

Kitchen and Laundry

10. Turn the dishwasher on only when full.

11. Use both sides of the sink when washing dishes by hand--one to wash, one to rinse.  Avoid washing dishes under running water.

12. Wash your dishes only once a day.

13. Buy and install a faucet aerator.

14. Keep a bottle of drinking water in the refrigerator to avoid running the tap to get a glass of cool water.

15. Pre-rinse clothes only when absolutely necessary.

16. Use the proper water level or load-size selection on the washing machine.

17. Don’t use or install in-sink garbage disposals.  These devices use about 11.5 gallons of water daily.  Encourage composting of organic wastes instead.

18. Clean vegetables in a pan of water, not under a running faucet.  Collected water can be used for your household plants.

Lawn and Garden

19. Water only when needed.  Frequency depends on the type of plants and soil conditions.

20. Water only as rapidly as the soil can absorb the water.

21. Water root areas of your plants to establish hardiness.  Shallow roots are less likely to withstand drought condition.

22. Install a trickle or drip irrigation system for a slow, steady supply of water to the plant roots.  This method can save up to 60 percent of the water used in other watering techniques.

23. Water the lawn in the evening when evaporation is less likely to occur.  Avoid watering during the heat of the day or when windy.

24. Use native plants when landscaping your lawn.  Generally, native plants require less care and water than other ornamental varieties.

25. Place a layer of mulch around plants and trees to avoid excessive evaporation.

26. Replace leaky or broken sprinklers and sprinkler heads promptly.

27. Consider water requirements when purchasing new plants.


28. Prevent water runoff from your sprinkler system.  Watering the sidewalk, gutter, or street wastes water.

29. Use a broom, not a hose, when cleaning driveways and walkways.

30. Use a hose with a shut-off nozzle to wash the car.

31. Locate the master water supply valve and label it.  The master supply valve can be easily turned off in the case of a major leak or broken pipe.

32. Clean gutters and down spouts manually instead of hosing them down.

(Tips quoted from the Water Saving Guidelines Pamphlet, City of Walla Walla Water Division, Washington State Department of Health, and Washington State Department of Ecology)

Links to additional websites about water:

            Information about the city of Walla Walla’s water supply

            Walla Walla Basin Watershed Council

            City of Walla Walla Water Division

            Walla Walla County Conservation Districts

            U.S. Army Corps of Engineers Walla Walla District Water Management Site

            U.S.G.S. Water Resources of Washington State


Learn about how to become active in your local watershed:


Link to learn more about national water issues: