Watershed Health

Maintaining Healthy Water Quality 

The Puget Sound region is a unique network of mountain peaks, plateaus, rivers, lakes, and marine wCollecting water samplesaters. These natural wonders make Pierce County a beautiful place to visit, live, work and play. Maintaining healthy water quality in the streams, rivers and lakes that connect the Cascade Mountains to Puget Sound is essential to the quality of life and prosperity of Pierce County residents, businesses and wildlife.

Water quality has declined in most areas of Pierce County as the population and development have grown over the past century. The most common water quality concerns in Pierce County streams are high levels of bacteria, nitrogen and phosphorus, elevated summer temperatures and low dissolved oxygen concentrations.

Water Quality Data
  1. About Water Quality Data
  2. About BIBI Scores
  3. About WQI Scores

Our water quality specialists go out in the field monthly to monitor water quality at streams throughout Pierce County. We also collect benthic samples from a subset of streams every summer. Below are 2021 results from our stream monitoring program. This graphic below summarizes results between October 1, 2021, and September 30, 2022.

Watershed health is classified into three categories — Poor, Moderate and Good — using Benthic Index of Biotic Integrity (BIBI) scores and Water Quality Index (WQI) scores. Click on the tabs above to learn more about how these data points paint a water quality picture.

Click on the picture below to view a larger, clearer version of the graphic.

Watershed Health - 2022
The Monitoring Unit (Water Quality Section) helps ensure Pierce County meets the requirements of the National Pollutant Discharge Elimination System (NPDES) Phase I Municipal Stormwater Permit. Pierce County’s monitoring team collects local data to measure whether water quality is getting better or worse and identify patterns in healthy and impaired Puget lowland streams and Puget Sound urban shoreline areas. We also collect data for NPDES driven watershed modeling and Total Maximum Daily Load (TMDL) projects.
Clarks Creek TMDL Project 
The Clarks Creek restoration plan was created to restore water quality and protect the watershed by identifying and prioritizing the treatment of stormwater flow and the reduction of sediment in the creeks of the watershed. The improvement plan is funded through a combination of local dollars and local, state and federal grant monies. You can read more about the Clarks Creek TMDL Project on our project webpage.
Water Level and Weather Data
There are many water level and weather monitoring stations spread throughout Pierce County. Local live weather station data can be found here. Our water quality data portal can be found here.
Shellfish Protection 
Pierce County conducts shellfish beach sampling and coordinates with the Tacoma-Pierce County Health Department and other partners on programs to keep pollutants out of shellfish beds.

Carol Falkenhayn Maloy

Water Quality Supervisor

Phone: (253) 377-6866


7:30 a.m.–4:00 p.m.

Mailing Address:

2702 S 42nd St, Ste 109

Tacoma, WA 98409-7322