Washington

Average Groundwater Temperatures for the Cities in Washington State

Average groundwater temperatures play an important role in determining which tankless water heater to purchase. The reason for this is because in colder climates the groundwaters starting temperature is colder than in warmer climates. This causes the tankless water heater to work harder to increase the water temperature in colder climates, which in turn causes the flow rate to decrease in parallel. For example, if the starting water temperature is 52°F and you need to raise the water temperature to 110°F. Then your tankless water heater needs to be capable of raising the water temperature by 58°F and still have enough flow to support the fixtures you want to simultaneously run.

 

How Flow Rates are Affected by Temperature

In the example below, you can see the impact that temperature has on flow rates. This example is based on a tankless water heater that has a flow rate rated for 8 GPM.

 

Temperature Zone Efficiency
+71 °F 100% (8 GPM)
61 - 70 °F 73% (5.8 GPM)
51 - 60 °F 58% (4.6 GPM)
41 - 50 °F 48% (3.8 GPM)
< 40 °F 41% (3.2 GPM)

The efficiency percentage is an average based on Siebel TempraRinnai RU199, and ECO90 tankless water heater models.

 

Flow Rates of Appliances

Based on the corresponding flow rates for each appliance that are listed. A tankless water heater that is rated with a flow rate of 8 GPM (gallons per minute) is capable of running these items at the same time in regions with an average groundwater

temperature of 72°F.

 

Shower = 3 GPM

Kitchen Sink = 1.5 GPM

Washing Machine = 2.5 GPM

Total = 7 GPM

 

If you take this same exact tankless water heater and install it in a region that has an average groundwater temperature of 52°F (green zone). This will lower that tankless water heater's max GPM output to 4.64 GPM.

 

Shower = 3 GPM

Kitchen Sink = 1.5 GPM

Total = 4.5 GPM

 

As you can see before purchasing a tankless water heater it's important to know the impact temperature has on its ability to heat water and its effect on the total GPM needs of your household.

 

Washington Groundwater Temperature Yearly Average

City and Zip Codes Groundwater Temperature

Seattle Metro Area

98101 | 98102 | 98103 | 98104 | 98105 | 98106 | 98107 | 98108 | 98109 | 98112 | 98115 | 98116 | 98117 | 98118 | 98119 | 98121 | 98122 | 98125 | 98126 | 98133 | 98134 | 98136 | 98144 | 98146 |98148 | 98154 | 98155 | 98158 | 98164 | 98166 | 98168 | 98174 | 98177 | 98178 | 98188 | 98195 | 98198 | 98199

52°F

Spokane

99201 | 99202 | 99203 | 99204 | 99205 | 99206 | 99207 | 99208 | 99212 | 99216 | 99217 | 99218 | 99223 | 99224

54°F

Tacoma Metro Area

98402 | 98403 | 98404 | 98405 | 98406 | 98407 | 98408 | 98409 | 98416 | 98418 | 98421 | 98422 | 98433 | 98443 | 98444 | 98445 | 98446 | 98447 | 98465 | 98466

54°F

Vancouver

98660 | 98661 | 98662 | 98663 | 98664 | 98665 | 98682 | 98683 | 98684 | 98685 | 98686

51°F

Bellevue

98004 | 98005 | 98006 | 98007 | 98008

52°F

Kent

98030 | 98031 | 98032 | 98042

54°F

Everett

98201 | 98203 | 98204 | 98207 | 98208

51°F

Renton

98055 | 98056 | 98057 | 98058 | 98059

51°F

Federal Way

98003 | 98023

52°F

Tri-Cities

99301 | 99336 | 99337 | 99338 | 99352 | 99354

52°F

Olympia

98501 | 98502 | 98506 | 98512 | 98513 | 98516

55°F

Bellingham

98225 | 98226 | 98229

51°F

Mount Vernon

98273 | 98274

51°F

Longview

98632

52°F

Whidbey Island

98236 | 98277 | 98278

53°F

Port Angeles

98362 | 98363

53°F

Sequim

98382

52°F

Yakima Valley

98901 | 98902 | 98903 | 98908

49°F

Walla Walla

99362

55°F

Moses Lake

98837

51°F

Ellensburg

98926

48°F

Wenatchee

98801

52°F

What Tankless Water Heater Should you buy if you Live in Washington State?

Since Washington's average groundwater temperature range is between 48°F and 55°F. It is recommended that you select a green zone or light blue zone Tankless Water Heater. To see the recommended Tankless Water Heaters that apply to the light blue and green zone temperatures please follow the link that corresponds to the region of your average groundwater temperature.

 

Temperature zone Recommended Tankless Water Heater
< 40 °F Tankless Water Heater Recommendations
41 - 50 °F Tankless Water Heater Recommendations
51 - 60 °F Tankless Water Heater Recommendations
61 - 70 °F Tankless Water Heater Recommendations
+71 °F Tankless Water Heater Recommendations
 

For more information, please contact HydroFLOW West