West Okoboji Lake is a cold, clear oligotrophic lake in Dickinson County, Iowa. Water quality is graded A based on 2 sampling years through 2024. Water clarity is declining over recent sampling years. Limited fish-species data available. Public access is available with 2 public boat landings. Compared to the 7 other monitored lakes in Dickinson County, West Okoboji Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-09-10. Grade methodology: LakeGrade methodology.
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West Okoboji Lake Water Quality Report Card (2026)
A printable one-page report card for West Okoboji Lake: grade, clarity, phosphorus, algae, multi-year trend, depth, and fish — with sources.
Swimming Safety
Based on E. coli testing, West Okoboji Lake frequently exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 19.1% of 209 samples across 7 seasons.
This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check Iowa’s current beach and health-department advisories before swimming.
Water Quality Grade: A, Excellent
Crystal clear, you can see 15.7 ft down. Chlorophyll-a: 2.6 µg/L. Trophic State Index: 39.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 15.7 ft | A |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 2.6 µg/L | A |
| Trophic State Index (TSI) | 39 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near West Okoboji Lake
Compare lakeside cabins, hotels, and vacation rentals near West Okoboji Lake in Dickinson County, Iowa — 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 West Okoboji Lake
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Fishing West Okoboji Lake
Water Quality Trend: → Stable
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.309 m/yr | 5 |
| Chlorophyll-a | ↑ Improving | -0.63 µg/L/yr | 5 |
Recreation & Access
Current Conditions
Latest reading Jul 6, 2026, 4:45 AM from USGS gauge 06604200. See live data ↗ — readings update every 15–60 minutes; this page refreshes on each build.
Water Temperature
West Okoboji Lake averages about 74°F at the surface in summer, usually warmest in Jul (about 78°F) and coldest in May (about 61°F). These are typical values by month — see Current Conditions above for the latest gauge reading.
Typical surface water temperature by month, from 101 field readings (2010–2023) via the EPA Water Quality Portal. See the full West Okoboji Lake water temperature breakdown →
Location & Depth Map
Free interactive depth-contour map of West Okoboji Lake, reaching a maximum surveyed depth of 135 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
County Ranking
Ranked #1 of 8 lakes in Dickinson County
Nearby Lakes in Dickinson County
Explore West Okoboji Lake across LakeGrade
Species activity outlook by water temperature and season
Top lakes and where to stay in the Iowa Great Lakes area
Where to stay at Iowa's top lakes, each with its grade
Low nutrients, clear water, excellent for swimming
Iowa's cleanest and most-polluted lakes, ranked
More Iowa Lake Rankings
Other Grade A Lakes in Iowa
More records, surveys & data sources
EPA Impairment Status
West Okoboji Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit IA 06-LSR-2066 · Official waterbody report · Matched by proximity (2.28 km)
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
15 EPA-permitted facilities operate within about 5 miles of West Okoboji Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Central Water SystemOkoboji · 0.8 mi away · NPDES IA0083879Recent violation
- Whitecap AdditionArnolds Park · 0.7 mi away · NPDES IA0052945
- Quiring Residence StormwaterOkoboji · 0.8 mi away · NPDES IA0053623
- Lakeside Ave. Infrastructure ImprovementsWahpeton · 0.8 mi away · NPDES IA0053299
- Sherwood ForestOkoboji · 0.8 mi away · NPDES IA0053342
- Wahpeton Street Improvements ProjectWahpeton · 0.9 mi away · NPDES IA0053631
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
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2024-09-10
Monitoring stations: 5