Our water and weather data is available to the public through an online portal called the Pierce County Water Data Viewer. This powerful interface offers access to over 300 monitoring stations where you can find data on water quality, weather, groundwater, and streamflow. You’ll also find data from our partners, including Pierce Conservation District sampling locations and USGS stream gauge stations. 

Interested to learn about the health of a particular stream? We use the Water Quality Index (WQI) score to track water quality status and trends in the county. A WQI score is based on 8 stream water chemical and physical parameters. Monthly WQI scores can go back to 2008 at some long-term monitoring sites. Annual and monthly WQI score time series for freshwater quality stations are available on the Water Data Viewer.  We also provide this information on a watershed basis on our Watershed Health webpage. For more information about the types of data available, please visit our Water Data Viewer.

Accessing the Data

You can access and download the data using a standard web browser. We have created four short tutorial videos to help you get started:

1. An introduction to the data portal basic functions and navigations 
2. Filtering data
3. Data availability by station type 
4. Data viewing and downloading

We have also produced a step-by-step written guide for downloading data:

• A Brief Tutorial for Downloading Groundwater Data

The terms of use are available on the Pierce County Water Quality Data Disclaimer. To access the data, you must agree with the terms, so please take a moment to review them. 

We are always improving the data portal. If you have any trouble with the site, begin by closing and reopening the webpage or using a different browser. If you need further assistance or would like to offer feedback on the site, please contact the Pierce County Water Quality Data Manager at [email protected].