Lake Pahoja
Lyon County, Iowa72 acresView mapDirections
Nutrients and algae run well above the regional average.
- Hypereutrophic
- Impaired · Pathogens (E. coli, fecal)
- #1 of 1 in the county
- Public access
Lake Pahoja in Lyon County, Iowa has a water quality grade of F (Algae-prone). Water clarity: 1.7 ft visibility. Phosphorus: 218 µg/L. Chlorophyll-a (algae): 44.8 µg/L. Surface area: 71.5 acres.
- Clarity
- 1.7 ft
- Typical in September
- 69°F
- Area
- 72 acres
- Type
- Hypereutrophic
- Phosphorus
- 218 µg/L
- Chlorophyll-a
- 44.8 µg/L
- Trend
- ↑ Improving
- Public access
- Yes
Stays via Stay22
Stays near Lake Pahoja
Compare lakeside cabins, hotels, and vacation rentals near Lake Pahoja in Lyon 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. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Lake Pahoja are listed below.
Top-rated places to stay near Lake Pahoja
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Watch Lake Pahoja’s letter
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Free interactive depth-contour map of Lake Pahoja, reaching a maximum surveyed depth of 24 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
Lake Pahoja is a 72-acre highly nutrient-loaded hypereutrophic lake in Lyon County, Iowa. Water quality is graded F based on 2 sampling years through 2024. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-09-09. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyBacteria advisory
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 F is nutrients and algae, not a swimming clearance. Lake Pahoja is listed impaired under Clean Water Act §303(d) (IR 5) for pathogens (E. coli, fecal). Check local advisories before you swim.
Water Quality Grade: F (Algae-prone)
Very murky, less than 1.7 ft of visibility. Phosphorus 218 µg/L. Chlorophyll-a 44.8 µg/L. TSI 73. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.7 ft | Not graded |
| Phosphorus | 218 µg/L | Poor |
| Chlorophyll-a (Algae) | 44.8 µg/L | Poor |
| Trophic State Index (TSI) | 73 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Water Temperature
Lake Pahoja typically sits around 69°F at the surface in September. Summer average is about 75°F. Usually warmest in Jul (about 80°F) and coldest in May (about 67°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 31 field readings (2010–2023) via the EPA Water Quality Portal. See the full Lake Pahoja water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 72 acres |
| Public Access | Yes |
No bathymetric survey has been published for Lake Pahoja, so its depth is not documented here.
Fishing Lake Pahoja
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.127 m/yr | 4 |
| Phosphorus | ↑ Improving | -32.95 µg/L/yr | 4 |
| Chlorophyll-a | ↓ Declining | +8.27 µg/L/yr | 4 |
Reservoir Info (USACE NID)
Lake Pahoja is a man-made reservoir impounded by the Lake Pahoja Dam (completed 1974), built primarily for fire protection, stock, or small fish pond on the TR-KLONDIKE CREEK; earth-type dam, 50 ft tall and 1,305 ft long.
- Surface area
- 71.5 ac
- Normal storage
- 893 ac-ft
- Max storage
- 2,283 ac-ft
- Drainage area
- 6.09 sq mi
- Hazard class
- Significant
- Owner
- Lyon County Conservation Board
All listed purposes: Fire Protection, Stock, Or Small Fish Pond;Recreation.
Source: USACE National Inventory of Dams, NID ID IA00604 · Operator website
EPA Impairment Status
Lake Pahoja 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 06-BSR-1532 · Official waterbody report
Regulated Pollution Sources Nearby
6 EPA-permitted facilities operate within about 5 miles of Lake Pahoja under Clean Water Act (NPDES) discharge permits. 2 facilities have a reported Clean Water Act violation in the past three years.
- Larchwood 1447 LlcLarchwood · 4.3 mi away · NPDES IA0052919Recent violation
- Larchwood City Of StpLarchwood · 4.9 mi away · NPDES IA0047333Recent violation
- Damon Bahnson Combined OperationInwood · 3.9 mi away · NPDES IA0084239
- Thane Fluit FeedlotInwood · 4.3 mi away · NPDES IA0053196
- Austin FluitLarchwood · 4.6 mi away · NPDES IA0084204
- Novartis Animal Health Us, Inc. (Changed To Elanco, Changed To Avach)Larchwood · 4.7 mi away · NPDES IA0073831
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.
County Ranking
Ranked #1 of 1 lakes in Lyon County
Nearby Lakes in Lyon County
Frequently asked questions about Lake Pahoja
Where is Lake Pahoja?
- Lake Pahoja is a lake in Lyon County, Iowa. LakeQuality grades it F for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Lake Pahoja?
- Lake Pahoja in Lyon County, Iowa has a water quality grade of F (Algae-prone). Water clarity: 1.7 ft visibility. Phosphorus: 218 µg/L. Chlorophyll-a (algae): 44.8 µg/L. Surface area: 71.5 acres.
Is Lake Pahoja safe to swim in?
- The F is nutrients and algae, not a swimming clearance. Lake Pahoja is listed impaired under Clean Water Act §303(d) (IR 5) for pathogens (E. coli, fecal). Check local advisories before you swim.
What is the water temperature of Lake Pahoja?
- Lake Pahoja typically sits around 69°F at the surface in September, from 31 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
Explore Lake Pahoja across LakeQuality
17.4 mi away · 100 ft
Species activity outlook by water temperature and season
Where to stay at Iowa's top lakes, each with its grade
Very high nutrients, dense algae, poor clarity
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Where this data comes from
52 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_WQX52 samples · 2021–2024
Analytical methods
- Unknown
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- In-Vitro Determination of Chlorophyll
- ISU modification of APHA 2130-B
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)