Lake Keomah Beach
Mahaska County, IowaView mapDirections
Not enough samples to grade — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). No letter yet. Here is what we do have.
- Impaired · Algal growth
- Public access
- Limited data
Lake Keomah Beach in Mahaska County, Iowa is not rated for water quality — its monitoring record does not meet the evidence bar.
- Trend
- ↑ Improving
- Public access
- Yes
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Watch Lake Keomah Beach’s letter
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Why Lake Keomah Beach has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Lake Keomah Beach, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by Iowa DNR and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Lake Keomah Beach is a lake in Mahaska County, Iowa. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-05-29. Grade methodology: LakeQuality methodology.
What Lake Keomah Beach is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming Safety
Not ratedBacteria F · advisory
Based on E. coli testing, Lake Keomah Beach routinely exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 25% of 100 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 measurements for Lake Keomah Beach
These readings exist but are not enough for an A–F grade — see why.
No clarity data.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples |
Recreation & Access
- Lake Keomah State ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Lake Keomah Beach
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.006 m/yr | 4 |
| Phosphorus | ↑ Improving | -28 µg/L/yr | 3 |
| Chlorophyll-a | ↑ Improving | -3.56 µg/L/yr | 4 |
EPA Impairment Status
Lake Keomah Beach is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IA 03-SSK-930 · Official waterbody report · Matched by proximity (0.24 km)
Graded lakes near Lake Keomah Beach
Lake Keomah Beach has no grade, but these lakes within a short drive do.
Nearby Lakes in Mahaska County
Frequently asked questions about Lake Keomah Beach
Where is Lake Keomah Beach?
- Lake Keomah Beach is a lake in Mahaska County, Iowa. LakeQuality has not rated this lake (UNRATED) — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years).
What is the water quality grade for Lake Keomah Beach?
- Lake Keomah Beach in Mahaska County, Iowa is not rated for water quality — its monitoring record does not meet the evidence bar.
Is Lake Keomah Beach safe to swim in?
- Based on E. coli testing, Lake Keomah Beach routinely exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 25% of 100 samples across 7 seasons. That works out to a bacteria swim-safety grade of F — a historical summary of past testing, not a current reading. Lake Keomah Beach is not rated for water quality — its monitoring record does not meet the evidence bar. Bacteria levels can spike quickly after heavy rain, so always check Iowa's current beach and health-department advisories before you swim.
Are there boat ramps on Lake Keomah Beach?
- Lake Keomah Beach has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Lake Keomah State Park. Public access is listed as yes.
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Where this data comes from
28 measurements from 1 monitoring station, 2021–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Iowa DNR Surface Water Monitoring Data
21IOWA_WQX28 samples · 2021–2024
Analytical methods
- 2130 B ~ Nephelometric Method
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
Named boat-access points from the USGS National Boat Ramps inventory