The Boise River is a mostly healthy river, according to a recently published report card from Idaho Rivers United.The report card compares key indicators of a healthy river against established benchmarks. Those indicators includ e average river temperature, pH level, dissolved oxygen levels, turbidity, biochemical dissolved oxygen levels, prevalence of nitrates phosphates, total coliform bacteria, and finally trash removal.RELATED | 3,800 pounds of trash collected from Boise River; local group says there's more to gatherIdaho Rivers United completed its testing between June and November of 2025 at three locations: Barber Park, the Parkcenter Boat Ramp, and the Americana Bridge. Overall, 103 water quality surveys were conducted.The Boise River got top marks for turbidity, pH levels, average temperature, and trash removed from the waterway. Areas where the Boise River fell short in terms of riparian health included elevated levels of nitrogen, most likely due to fertilizers used in the Boise River basin. Other areas that could be improved included dissolved oxygen levels and biochemical oxygen demand, the latter of which indicates how much oxygen is available in the river for bacteria vs. aquatic species such as trout.River enthusiasts who wish to get involved in supporting a healthy Boise River can volunteer with Idaho Rivers United by joining its Boise River Stewards program.Learn More: Boise River StewardsIdaho Rivers United | Boise River Report Card: Temperature (measured in degrees Celsius): Average 12.7C Ideal Temperature: <22C for cold water aquatic organisms and <13C for salmonid spawningThe results ranged from 6C to 20C; these temperatures are typical for the Boise River and support most cold-water species. Warmer days later in the season pushed temperatures toward 20C, which is not uncommon for shallow, sunlit rivers.pH Level: Average 7.32 Ideal range: 6.0-8.0The ideal range for healthy freshwater streams is between 6.0 and 8.0. A pH near neutral supports a wide variety of fish and other aquatic organisms, meaning the Boise River is nearly perfect in this regard.Dissolved Oxygen (measured in milligrams per liter - mg/L): Average DO 4.27 mg/L Omitting test results with 0s, average is 4.5 mg/L Range: 8+ mg/L is excellent; 5-6 mg/L supports aquatic growth and activity; <53 mg/L starts stressing aquatic organisms and is not sustainable long term; <3 mg/L is extremely stressful to aquatic life.Due to limitations of the testing kits, not enough precision was possible to provide an accurate representation of DO levels. We believe the 4.27 mg/L result may be inaccurate, as it would result in lower aquatic life populations than what we can observe in the river. Some results came back as 0 mg/L, which is nearly impossible for rivers; they would have to be slow-moving and heavily polluted. Because it is highly unlikely that the Boise River contains no dissolved oxygen, recordings of 0 mg/L were excluded, resulting in a revised average DO concentration of 4.5 mg/l. However, this average DO level still falls near the lower limit of fish tolerance and is unsuitable for prolonged exposure.Many readings fell in the fair category, with some excellent values and some low readings. This indicates the river generally supports aquatic life, though oxygen can dip during warmer or slower-flow periods.Turbidity (measured in Jackson Turbidity Units - JTU): Average turbidity: 15 JTU Range: 0100 JTU (0=excellent, >0-40 is good; >40-100 is fair; >100 is poorThe river stayed consistently clear, with most readings well within the healthy range for recreation and wildlife.Biochemical Dissolved Oxygen (measured in milligrams per liter - mg/L): Average BOD: 3.28 mg/L Ideal level: <2 mg/L >8 mg/L would indicate poor water qualityLower BOD values mean the river isnt overloaded with organic pollution. Boise River values suggest fair water quality, with some oxygen depletion from decaying materials.Nitrates (measured in milligrams per liter - mg/L): Average: 4.24 mg/L (Fair) Range: 0.1 - 10 mg/L 0.1-1 mg/L is excellent; 1-3 mg/L is good; 3-5 mg/L is fair; >5 mg/L is poor; 10 mg/L is EPAs max contamination level drinking water standardNitrate levels hover near the threshold of natural background levels, but well below drinking water limits. These concentrations are typical for an urban river and not high enough to cause algae problems.Phosphates (measured in milligrams per liter - mg/L): Average: 2.48 mg/L Ideal range: <0.03 mg/L; >0.1 mg/L indicates poor water quality. *0.07 mg/L is the TMDL for the Boise river past ParmaPhosphate levels tested high, however the test kits used did not have the ability to read small concentrations or provide precise measurements. The reported results were too sporadic to find a pattern or fit a trendline. The results have been deemed inconclusive due to the testing equipment not producing reliable results.Total Coliform Bacteria:The tests employed simply return a result of positive or negative, but no indication of concentration level; around 75% of our results were positive. To get a true sense of whether the river is host to a worrisome level harmful coliform bacteria, further testing is necessary to identify the kind of bacteria and that quantifies the number of colonies found. Given the limitations of the equipment used, these results indicate the presence of coliform bacteria but do not assess whether they pose a health concern.Trash RemovalAnother aim of the Report Card is to identify and highlight trash removal from in and around the Boise River. As previously mentioned, efforts led by the Boise River Stewards resulted in 937 pounds of trash being picked up during 15 cleanups. Overall, IRU organized 23 cleanups in 2025 that removed 3,850 pounds of trash! Our aim for future iterations of the Boise River Report Card is to include numbers from other organizations hosting cleanups. ...read more read less