Washington Lake is a productive, nutrient-rich eutrophic lake in Jackson County, Missouri. Water quality is graded F based on 2 sampling years through 2024. Overall water quality is declining over recent sampling years. Compared to the 26 other monitored lakes in Jackson County, Washington Lake ranks #25 for water quality.
Source: EPA Water Quality Portal sampling records, Missouri DNR, last sampled 2024-09-05. Grade methodology: LakeGrade methodology.
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Swimming Safety
Based on E. coli testing, Washington Lake routinely exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 54.5% of 11 samples across 4 seasons.
This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check Missouri’s current beach and health-department advisories before swimming.
Water Quality Grade: F, Very Poor
No clarity data. Phosphorus level: 96.2 µg/L. Chlorophyll-a: 36.6 µg/L. Trophic State Index: 68.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No data | |
| Phosphorus | 96.2 µg/L | F |
| Chlorophyll-a (Algae) | 36.6 µg/L | F |
| Trophic State Index (TSI) | 68 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Washington Lake
Compare lakeside cabins, hotels, and vacation rentals near Washington Lake in Jackson County, Missouri — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Washington Lake
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Fishing Washington Lake
Water Quality Trend: ↓ Declining
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Phosphorus | ↓ Declining | +97.8 µg/L/yr | 2 |
| Chlorophyll-a | ↓ Declining | +2.16 µg/L/yr | 3 |
Water Temperature
Washington Lake averages about 78°F at the surface in summer, usually warmest in Jul (about 81°F) and coldest in May (about 70°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 38 field readings (2010–2022) via the EPA Water Quality Portal. See the full Washington Lake water temperature breakdown →
Location
County Ranking
Ranked #25 of 27 lakes in Jackson County
Cleaner Lakes Within 30 Miles
Washington Lake holds Grade F. 3 nearby lakes hold higher grades.
- CBlue Valley LakeJackson County · 4.2 mi · Two grade letters higher (F → C)
- DValley LakeJackson County · 1.8 mi · Higher grade (F → D)
- FLake of the Woods-KcJackson County · 6.9 mi · Higher overall water quality score
Nearby Lakes in Jackson County
Explore Washington Lake across LakeGrade
More Missouri Lake Rankings
Other Grade F Lakes in Missouri
Eutrophic Lakes in Missouri
More records, surveys & data sources
Regulated Pollution Sources Nearby
6 EPA-permitted facilities operate within about 5 miles of Washington Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 1 facility has a reported Clean Water Act violation in the past three years.
- Kc Westside WwtpKansas City · 2.3 mi away · NPDES MO0024929MajorRecent violation
- Holland Company, Dba M-Bar-DKansas City · 1.3 mi away · NPDES MO0127507
- First Transit Inc #55433Kansas City · 1.6 mi away · NPDES MONX00254
- Pbi Gordon Corp Glp And WarehouseKansas City · 1.6 mi away · NPDES MONX00657
- Pbi Gordon Corp R And D OfficeKansas City · 1.6 mi away · NPDES MONX00656
- Faultless BrandsKansas City · 2 mi away · NPDES MONX01050
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Data Sources
Water quality data from the EPA Water Quality Portal
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2024-09-05
Monitoring stations: 1