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Water Source

Water supply conditions as of Sept. 17, 2026

We have passed peak summer temperatures and expect rain in the coming weeks. Currently, we have ample water supplies from our groundwater and surface water sources, and do not anticipate a water shortage this year. We have yet to determine the impact of this year’s “very strong” El Niño. We will continue to monitor conditions as we progress into fall, and we recommend our customers use water wisely.

Water Supply Indicator

Critical Abundant

How to read the Water Supply Indicator

  • Blue — Abundant: Average to wet year. Surplus water supply.
  • Green — Ample: Near normal conditions. Water supply can meet customer needs.
  • Yellow — Adequate: Slightly drier than normal.
  • Orange — Reduced: Water supply is approaching minimum availability; monitor for water shortage response measures.
  • Red — Critical: Water supply reserves are critically low; monitor for restriction notices.

The Tacoma Water Supply Indicator (WSI) can help inform you about changing water supply conditions. Our water resource engineers developed it to monitor our primary water source, the Green River Watershed. Because conditions vary significantly from county to county and from month to month, the WSI provides updated water messaging for Tacoma Water customers. 

Water sources

The source of our water supply varies throughout the year, depending on the season, weather, snowpack level, inflows, and water storage conditions. 

The minimum amount of water we can reliably produce on any day of a given year is 107 million gallons per day (we call this number the Firm Yield). The average use is approximately 50 million gallons per day (this doesn’t include how much water we produce for the other three partner utilities in the regional water supply system). Note that our peak use during the summer may be double this average, and could exceed our Firm Yield in some cases. 

Below is the typical amount of water available by the source:
  • Green River supply: 73 million gallons per day
  • Second Green River supply: 27 million gallons per day on average (interruptible share of regional water supply system; includes storage)
  • Local wells: 40 million gallons per day
  • North Fork wells (alternative Green River supply – not additive to other sources): 60 million gallons per day

Most of the time, we can use water wisely and not be concerned about running low. However, sometimes we experience dry conditions. During those times, especially when our water supply indicator lands in the red zone, we could ask that you reduce your water use or require you to use less water.  

If this happens, we’ll provide plenty of clear communication in advance and place information online, on our social media accounts, and in our newsletter(s). We’ll include recommendations and offer solutions about what you should and should not do. Updates will also include when we expect to return to stability. 

To help conserve water, we encourage customer to use WaterSense-labeled fixtures and EnergyStar-labeled appliances and fix leaks. Customers can also minimize water use outside while maintaining a healthy landscape. 

Our water resource engineers monitor the health of our water supply every day. Multiple agencies also report daily snow depth, water that comes from the snowpack (snow water equivalent), total rainfall, Eagle Gorge Reservoir storage quantities, and Green River inflow and observed runoff. We compile this into the Water Supply Index model and produce an overall score. Then, we compare these scores to Washington’s history (usually 30 to 60 years back). We also monitor the weather models from the National Weather Service’s Climate Prediction Center, including temperature precipitation forecasting and weather anomalies such as El Nino and La Nina. 

Tacoma participates in a fisheries resource management group with federal, state, and local jurisdictions to safeguard our native salmon and steelhead species in the Green River. We use a portion of Tacoma’s storage reserves for this purpose each year. 

In particularly challenging years, we use the South Tacoma Wellfield to supplement our water supplies. This means we can reserve adequate storage for boosting natural stream flows and maintaining healthy fish habits.

We depend on many partner agencies to share their data with us as we analyze our water situation in any given year. You can look at these datasets by visiting the following websites from our partner: 

Our water source engineers are thinking long-term about what water we need and is available for our growing service area. We always look 50 years into the future to make sure we still have all the water we need then, even as we face climate change impacts. You can soon read these plans and how we did our analysis in our upcoming Integrated Resource Plan. If we find ourselves in a drought with a water shortage, we have a plan for what to do. 

Bottle filling stations are a partnership between Tacoma Water, Parks Tacoma, and the City of Tacoma Public Works Department. Parks Tacoma owns and operates them and provides regular maintenance and filter replacements. They also include water fountains and some have pet bowls. Generally available April through October, the stations show our commitment to supply our community with clean, reliable drinking water.  

If you are impacted by a temporary water service interruption, you can use these filling stations as an alternate water source: 

  • Verlo Playfield: 4321 McKinley Ave.  
  • Ruston Way – Dickman Mill Park: 2423 Ruston Way  
  • Point Defiance Park: 5400 N. Pearl Street (near duck pond)  
  • STAR Center: 3873 S. 66th Street (near playground)  
  • McKinley Business District: Corner of E. McKinley and E. Wright Ave. (next to bus station)  
  • Lincoln Business District: Corner of S. 38th Street and S. Yakima Ave. (by bus stop on south side)