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Has the Rain Helped the Region’s Water Supply? Are Customers Using Less Water?

The region’s water consumption has dropped from an average of 149 mgd on Sept 18 to 117 mgd as of Oct 2. That’s good news! Let’s keep it up and reach our goal of 100 mgd or less.

In the 10 days since Seattle Public Utilities (SPU) began asking its 1.5 million customers to voluntarily reduce their water use, the region has seen a fair amount of wet weather.   

“It was dry this weekend, but this past week, it rained buckets of water – on and off,” said South Seattle resident Keiron Goodwin. 

As the autumn season began, so did the down pour of intense rain hitting Seattle neighborhoods on various days, which has Goodwin and many others asking, “Is the region getting enough rain to replenish its mountain reservoirs?” 

The short answer is, unfortunately, no.  According to SPU’s Water Resources Planner Elizabeth Garcia, while the rain showers have been welcomed, they have not been sufficient to make up for the water deficit the region is trying to overcome due to the unusually dry summer.   

“I love seeing the rain, especially now, and every little bit helps,” said Garcia. “But to put things in perspective, we are trying to make up for an extremely dry summer. On average, we get about 26 inches of rain in our mountain reservoirs from May 1 to October 1. This year, we only got ten inches in that same period.” 

What the region needs, explains Garcia, is sustained rainfall where it counts the most. In other words, there needs to be enough rain falling in our reservoirs in the Tolt and Cedar River Watersheds, located in the Cascade Mountains. Those reservoirs continue to be below average for this time of year, despite the recent rain.  

Additionally, SPU looks out months ahead using forecasts, seasonal outlooks, and hydrologic modeling to estimate future reservoir conditions. This year’s El Nino weather patterns have the Utility planning for a warmer and dryer fall and winter – meaning it may take longer for the region’s reservoirs to refill. All these conditions are key factors in SPU’s continued request for customers to help the region’s water supply recover by using less water.      

“We’ll get there, and customers are starting to do their part,” said Anna Dyer, SPU Water Conservation Manager. The Utility is encouraged by a regional drop in water consumption.  

On September 18, three days before SPU activated the Voluntary Stage of its Water Shortage Contingency Plan and started asking customers to reduce their water use, the average water consumption for the region was 149 million gallons per day (mgd). One week later, on September 25, average consumption had dropped to 131 mgd.  

“We think that reduction was partially attributed to the wet weather since customers tend to use less water when it rains,” said Dyer. “But we also know that our customers are consciously working to reduce their water use.” 

The combination of the rain dampening water consumption and the efforts of Seattle-area customers have the region moving in the right direction and getting closer to the goal of 100 mgd or less. The latest average consumption, as of October 2, has the region at 117 mgd.  

“That’s great news. I want to thank our customers for responding to our request to reduce water use, and I encourage them to keep it up,” said Dyer.

Learn more

There are lots of different ways for all families and businesses to use less water. Go to or download our water-saving tips flyer in multiple languages.

Stay tuned for our next update on the region’s water supply, which will be published on this blog on Tuesday, October 10. For more details about the region’s water supply, check SPU’s Water Supply Conditions web page updated weekly.