The Cleanest Water in Washington State

View in ChartLab

Use the drop-down list to examine the Top 10 or Bottom 10 testing stations, or use the Wildcard (*) option to view all available testing sites together.

The visualization above shows the ranking of the results of the latest Water Quality Index tests performed by the State of Washington. Washington State is known for its scenic mountain ranges, diverse climate, and crystal clear water and has published the following dataset, which tracks a number of metrics for the 2015 Water Quality tests performed by the Department of Ecology:

Metric Abbreviation Abbreviation Meaning Metric Weight
overallwqi_2015 Overall Water Quality Index (WQI) Score 1.00
wqifc Fecal Coliform count (mg FC / L H2O) .176
wqioxy Dissolved O2 (mg/L), ideally between 1-15 mg/L 0.187
wqiph Probability of Hydrogen (pH), ascending scale, 1-14 0.121
wqitemp Temperature Score for regularity 0.11
wqitp Total Phosphate (mg/L), essential compound for growth of plant and animal life in freshwater 0.11
wqitpn Total Persulfate Nitrogen (mg/L), contributes to animal and plant growth. 0.11
wqitss Total Suspended Solids (mg/L) 0.08
wqiturb Turbidity, a measurement which records the cloudiness of haziness of water in Nephelometric Turbidity Units (NTU) 0.09

These metrics all have individual weights applied based on their importance in the overall make-up of the health of a body of water, and have been converted to a 0-100 ascending scale. Such a scale can be ambiguous to the amateur viewer, thus conversions to qualitative words have also been provided below:

Range Quality
90-100 Excellent
70-90 Good
50-70 Medium
25-50 Bad
0-25 Very Bad

More information about the Water Quality Index, its methodology, or metrics, can be found here

Use the ChartLab visualization below, and the drop-down lists at the top of the screen to choose the metric, and compare the Top 10, Top 20, or Top 30, Bottom 10, Bottom 20, or Bottom 30 testing sites, or use the Wildcard option to view all available testing sites together.

View in ChartLab

The map below shows the Top 10 Overall Best WQI site locations noted in blue, and the Bottom 10 Overall Worst WQI site locations noted in red. The Station ID for each site is contained in the metadata, and may be returned with this SQL query in SQL Console and then cross-referenced to the Department of Ecology map (available on fortress.wa.gov):

SELECT tags.station_name AS "Station Name", value AS "WQI Overall Score", tags.station AS "Station Code"
  FROM "overallwqi_2015"
ORDER BY value DESC
  LIMIT 10

Highest Water Quality Test Sites

| Station Name                        | WQI Overall Score | Station Code |
|-------------------------------------|-------------------|--------------|
| Abernathy Cr nr mouth               | 99                | 25E060       |
| Hamma Hamma R @ Lena Creek Camp     | 94                | 16B130       |
| Twin Cr @ Upper Hoh Rd Br           | 94                | 20E101       |
| Methow R @ Twisp                    | 92                | 48A140       |
| Skokomish R nr Potlatch             | 91                | 16A070       |
| Cedar R nr Landsburg                | 91                | 08C110       |
| Little Pend Oreille R nr NatWildRef | 89                | 59B200       |
| Duckabush R nr Brinnon              | 88                | 16C090       |
| Yakima R @ Umtanum Cr Footbridge    | 88                | 39A055       |
| Columbia R @ Umatilla               | 88                | 31A070       |
SELECT tags.station_name AS "Station Name", value AS "WQI Overall Score", tags.station AS "Station Code"
  FROM "overallwqi_2015"
ORDER BY value ASC
  LIMIT 10

Lowest Water Quality Test Sites

| Station Name                     | WQI Overall Score | Station Code |
|----------------------------------|-------------------|--------------|
| NF Stillaguamish R @ Cicero      | 29                | 05B070       |
| SF Palouse R @ Pullman           | 34                | 34B110       |
| Palouse R @ Hooper               | 37                | 34A070       |
| Hangman Cr @ Mouth               | 39                | 56A070       |
| Crab Cr nr Beverly               | 42                | 41A070       |
| NF Stillaguamish R nr Darrington | 43                | 05B110       |
| Nooksack R @ Brennan             | 45                | 01A050       |
| Palouse R @ Palouse              | 45                | 34A170       |
| Walla Walla R nr Touchet         | 49                | 32A070       |
| Yakima R @ Kiona                 | 49                | 37A090       |

Find your favorite waterway in the data above, or discover a new one and enjoy all the natural beauty that Washington has to offer.