Lost Grove Lake
Scott County, Iowa350 acresView mapDirections
Iowa DNR publishes the water-quality measurements for Lost Grove Lake. Here is what has been measured.
- Eutrophic
Lost Grove Lake in Scott County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 3.9 ft visibility. Phosphorus: 31 µg/L. Chlorophyll-a (algae): 15.8 µg/L. Surface area: 350 acres.
Free interactive depth-contour map of Lost Grove Lake, reaching a maximum surveyed depth of 48 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
Lost Grove Lake is a 350-acre productive, nutrient-rich eutrophic lake in Scott County, Iowa. Overall water quality is declining over recent sampling years. Compared to the 4 other monitored lakes in Scott County, Lost Grove Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-08-26. Methodology: how these readings are compared.
Lost Grove Lake covers about 350 acres in Scott County. For a place on the water, look through cabin and lake-house rentals near Lost Grove Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
Swimming conditions
Readings onlyAlgae risk
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Lost Grove Lake is safe to swim in today is a call for the Iowa Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Lost Grove Lake
These are the measurements Iowa DNR publishes for Lost Grove Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 3.9 ft. Phosphorus 31 µg/L. Chlorophyll-a 15.8 µg/L. TSI 56.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3.9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 31µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 15.8µg/L | Fair GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 56 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Lost Grove Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Lost Grove Lake typically sits around 71°F at the surface in September. Summer average is about 76°F. Usually warmest in Jul (about 77°F) and coldest in May (about 64°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (64°F) to its warmest (77°F).
Typical surface water temperature by month, from 21 field readings (2015–2023) via the EPA Water Quality Portal. See the full Lost Grove Lake water temperature breakdown →
Lake Details
Surface area
350 acres
No bathymetric survey has been published for Lost Grove Lake, so its depth is not documented here.
Stays via Stay22
Stays near Lost Grove Lake
Compare lakeside cabins, hotels, and vacation rentals near Lost Grove Lake in Scott 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 Lost Grove Lake
Prices for Oct 23–25, 4 adults. Change dates on the map below.
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Fishing Lost Grove Lake
Water Quality Trend: Worsening
Based on 5 years of monitoring (2020–2024).
Water clarity
Improving5 years
Phosphorus
Worsening+43.2 µg/L/yr4 years
Chlorophyll-a
Worsening+3.18 µg/L/yr5 years
Reservoir Info (USACE NID)
Lost Grove Lake is a man-made reservoir impounded by the Lost Grove Lake (completed 2012), built primarily for recreation on the Lost Creek; earth-type dam, 75 ft tall and 1,165 ft long.
- Surface area
- 350 ac
- Normal storage
- 6,080 ac-ft
- Max storage
- 9,595 ac-ft
- Drainage area
- 7.1 sq mi
- Hazard class
- High
- Owner
- Iowa Department of Natural Resources
Source: USACE National Inventory of Dams, NID ID IA04083 · Operator website
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Lost Grove Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Princeton City Of StpPrinceton · 4.4 mi away · NPDES IA0033227Recent 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.
Nearby Lakes in Scott County
Frequently asked questions about Lost Grove Lake
Where is Lost Grove Lake?
- Lost Grove Lake is a lake in Scott County, Iowa. Its water-quality measurements are published by Iowa DNR and shown on this page as reported.
What is the water quality of Lost Grove Lake?
- Lost Grove Lake in Scott County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 3.9 ft visibility. Phosphorus: 31 µg/L. Chlorophyll-a (algae): 15.8 µg/L. Surface area: 350 acres.
Is Lost Grove Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Lost Grove Lake?
- Lost Grove Lake typically sits around 71°F at the surface in September, from 21 EPA Water Quality Portal field readings (2015–2023). That is a typical value for the month, not a live reading.
Explore Lost Grove Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Species activity outlook by water temperature and season
Where to stay at Iowa's top lakes, each with its readings
Iowa's cleanest lakes, ranked on agency measurements
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Eutrophic Lakes in Iowa
Where this data comes from
69 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Iowa DNR Surface Water Monitoring Data
21IOWA_WQX69 samples · 2020–2024
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)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Regulated discharger data from EPA ECHO (ICIS-NPDES)