Viking Lake
Montgomery County, Iowa148 acresView mapDirections
Nutrients and algae run well above the regional average.
- Hypereutrophic
- #1 of 1 in the county
- Public access
Viking Lake in Montgomery County, Iowa has a water quality grade of F (Algae-prone). Water clarity: 3.3 ft visibility. Phosphorus: 40 µg/L. Chlorophyll-a (algae): 32.7 µg/L. Surface area: 148 acres.
- Clarity
- 3.3 ft
- Typical in September
- 72°F
- Area
- 148 acres
- Type
- Hypereutrophic
- Trend
- ↑ Improving
- Public access
- Yes
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Stays near Viking Lake
Compare lakeside cabins, hotels, and vacation rentals near Viking Lake in Montgomery 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 Viking Lake are listed below.
Top-rated places to stay near Viking Lake
Prices for Sep 11–13, 4 adults. Change dates on the map below.
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Free interactive depth-contour map of Viking Lake, reaching a maximum surveyed depth of 36 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
Viking Lake is a 148-acre highly nutrient-loaded hypereutrophic lake in Montgomery 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 2024-09-30. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyAlgae risk
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. Check local advisories before you swim.
Water Quality Grade: F (Algae-prone)
Very murky, less than 3.3 ft of visibility. Phosphorus 40 µg/L. Chlorophyll-a 32.7 µg/L. TSI 61. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.3 ft | Not graded |
| Phosphorus | 40 µg/L | Fair |
| Chlorophyll-a (Algae) | 32.7 µg/L | Poor |
| Trophic State Index (TSI) | 61 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Water Temperature
Viking Lake typically sits around 72°F at the surface in September. Summer average is about 80°F. Usually warmest in Jul (about 83°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 102 field readings (2010–2023) via the EPA Water Quality Portal. See the full Viking Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 148 acres |
| Public Access | Yes |
No bathymetric survey has been published for Viking Lake, so its depth is not documented here.
Fishing Viking Lake
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.027 m/yr | 4 |
| Phosphorus | ↑ Improving | -5.2 µg/L/yr | 4 |
| Chlorophyll-a | → Stable | +0.17 µg/L/yr | 4 |
Reservoir Info (USACE NID)
Viking Lake is a man-made reservoir impounded by the Viking Lake Dam (completed 1957), built primarily for recreation on the DUNNS CREEK; earth-type dam, 69 ft tall and 1,220 ft long.
- Surface area
- 148 ac
- Normal storage
- 1,900 ac-ft
- Max storage
- 3,450 ac-ft
- Drainage area
- 3.42 sq mi
- Hazard class
- Significant
- Owner
- Iowa Department of Natural Resources
Source: USACE National Inventory of Dams, NID ID IA01366 · Operator website
Regulated Pollution Sources Nearby
3 EPA-permitted facilities operate within about 5 miles of Viking Lake under Clean Water Act (NPDES) discharge permits. 3 facilities have a reported Clean Water Act violation in the past three years.
- Dnr Viking Lake State ParkStanton · 1.1 mi away · NPDES IA0066036Recent violation
- Stanton City Of StpStanton · 4.3 mi away · NPDES IA0042978Recent violation
- Villisca City Of StpVillisca · 4.9 mi away · NPDES IA0032549Recent violation
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 Montgomery County
Nearby Lakes With Higher Grades
Viking Lake holds Grade F. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Montgomery County
Frequently asked questions about Viking Lake
Where is Viking Lake?
- Viking Lake is a lake in Montgomery County, Iowa. LakeQuality grades it F for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Viking Lake?
- Viking Lake in Montgomery County, Iowa has a water quality grade of F (Algae-prone). Water clarity: 3.3 ft visibility. Phosphorus: 40 µg/L. Chlorophyll-a (algae): 32.7 µg/L. Surface area: 148 acres.
Is Viking Lake safe to swim in?
- The F is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Viking Lake?
- Viking Lake typically sits around 72°F at the surface in September, from 102 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
Explore Viking Lake across LakeQuality
More Iowa Lake Rankings
Other Grade F Lakes in Iowa
Hypereutrophic Lakes in Iowa
Where this data comes from
53 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_WQX53 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
Regulated discharger data from EPA ECHO (ICIS-NPDES)