Bethel Lake
Boone County, MissouriView mapDirections
Clarity, phosphorus, and algae sit in the clean band for this region.
↑ up from C at the last regrade
- Eutrophic
- Impaired · Algal growth
- #3 of 10 in the county
Bethel Lake in Boone County, Missouri has a water quality grade of B (Good). Water clarity: 2.2 ft visibility. Phosphorus: 32.7 µg/L. Chlorophyll-a (algae): 9.5 µg/L.
- Clarity
- 2.2 ft
- Typical in August
- 83°F
- Type
- Eutrophic
- Phosphorus
- 32.7 µg/L
- Chlorophyll-a
- 9.5 µg/L
- Trend
- ↑ Improving
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Watch Bethel Lake’s letter
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Bethel Lake is a productive, nutrient-rich eutrophic lake in Boone County, Missouri. Water quality is graded B based on 2 sampling years through 2024. Overall water quality is improving over recent sampling years. Compared to the 9 other monitored lakes in Boone County, Bethel Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Missouri DNR, last sampled 2024-07-19. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyLow algae
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The B is nutrients and algae, not a swimming clearance. Bethel Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth. Check local advisories before you swim.
Water Quality Grade: B (Good)
Very murky, less than 2.2 ft of visibility. Phosphorus 32.7 µg/L. Chlorophyll-a 9.5 µg/L. TSI 58. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.2 ft | Not graded |
| Phosphorus | 32.7 µg/L | Good |
| Chlorophyll-a (Algae) | 9.5 µg/L | Good |
| Trophic State Index (TSI) | 58 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Water Temperature
Bethel Lake typically sits around 83°F at the surface in August. Summer average is about 83°F. Usually warmest in Jul (about 84°F) and coldest in May (about 75°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 14 field readings (2022–2024) via the EPA Water Quality Portal. See the full Bethel Lake water temperature breakdown →
Fishing Bethel Lake
Water Quality Trend: ↑ Improving
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.36 m/yr | 2 |
| Phosphorus | ↓ Declining | +15.5 µg/L/yr | 3 |
| Chlorophyll-a | ↑ Improving | -0.35 µg/L/yr | 3 |
EPA Impairment Status
Bethel Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MO_7199.00 · Official waterbody report · Matched by proximity (0.84 km)
County Ranking
Ranked #3 of 10 lakes in Boone County
Nearby Lakes in Boone County
Frequently asked questions about Bethel Lake
Where is Bethel Lake?
- Bethel Lake is a lake in Boone County, Missouri. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Bethel Lake?
- Bethel Lake in Boone County, Missouri has a water quality grade of B (Good). Water clarity: 2.2 ft visibility. Phosphorus: 32.7 µg/L. Chlorophyll-a (algae): 9.5 µg/L.
Is Bethel Lake safe to swim in?
- The B is nutrients and algae, not a swimming clearance. Bethel Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth. Check local advisories before you swim.
What is the water temperature of Bethel Lake?
- Bethel Lake typically sits around 83°F at the surface in August, from 14 EPA Water Quality Portal field readings (2022–2024). That is a typical value for the month, not a live reading.
Explore Bethel Lake across LakeQuality
More Missouri Lake Rankings
Other Grade B Lakes in Missouri
Eutrophic Lakes in Missouri
Where this data comes from
46 measurements from 1 monitoring station, 2022–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Univ. of Missouri, Columbia
UMC46 samples · 2022–2024
Analytical methods
- Depth, Secchi disk in meters
- 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database