Lower Pine Lake
Hardin County, Iowa85 acresView mapDirections
Nutrients and algae run well above the regional average.
- Hypereutrophic
- Impaired · Algal growth
- #2 of 2 in the county
- Public access
Lower Pine Lake in Hardin County, Iowa has a water quality grade of F (Algae-prone). Water clarity: 1.3 ft visibility. Phosphorus: 187 µg/L. Chlorophyll-a (algae): 73.5 µg/L. Surface area: 85 acres.
- Clarity
- 1.3 ft
- Typical in September
- 72°F
- Area
- 85 acres
- Type
- Hypereutrophic
- Trend
- ↑ Improving
- Public access
- Yes
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Stays near Lower Pine Lake
Compare lakeside cabins, hotels, and vacation rentals near Lower Pine Lake in Hardin 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 Lower Pine Lake are listed below.
Top-rated places to stay near Lower Pine Lake
Prices for Sep 11–13, 4 adults. Change dates on the map below.
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Watch Lower Pine Lake’s letter
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Free interactive depth-contour map of Lower Pine Lake, reaching a maximum surveyed depth of 16 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
Lower Pine Lake is a 85-acre highly nutrient-loaded hypereutrophic lake in Hardin 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 with 2 public boat landings. Compared to the 1 other monitored lakes in Hardin County, Lower Pine Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-10-28. Grade methodology: LakeQuality methodology.
What Lower Pine Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch2 documented ramps
Swimming Safety
Grade onlyBacteria A · 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.
Based on E. coli testing, Lower Pine Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 25 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: F (Algae-prone)
Very murky, less than 1.3 ft of visibility. Phosphorus 187 µg/L. Chlorophyll-a 73.5 µg/L. TSI 75. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.3 ft | Not graded |
| Phosphorus | 187 µg/L | Poor |
| Chlorophyll-a (Algae) | 73.5 µg/L | Poor |
| Trophic State Index (TSI) | 75 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Water Temperature
Lower Pine Lake typically sits around 72°F at the surface in September. Summer average is about 77°F. Usually warmest in Jul (about 81°F) and coldest in May (about 63°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 38 field readings (2010–2023) via the EPA Water Quality Portal.
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 85 acres |
| Public Access | Yes |
No bathymetric survey has been published for Lower Pine Lake, so its depth is not documented here.
Recreation & Access
- Pine Lake State ParkPublic
- Pine Lake State ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Lower Pine Lake
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.034 m/yr | 5 |
| Phosphorus | ↑ Improving | -13.8 µg/L/yr | 4 |
| Chlorophyll-a | ↓ Declining | +11.78 µg/L/yr | 5 |
Reservoir Info (USACE NID)
Lower Pine Lake is a man-made reservoir impounded by the Lower Pine Lake Dam (completed 1922), built primarily for recreation on the PINE CREEK; earth-type dam, 33 ft tall and 450 ft long.
- Surface area
- 85 ac
- Normal storage
- 360 ac-ft
- Max storage
- 924 ac-ft
- Drainage area
- 15.47 sq mi
- Hazard class
- Significant
- Owner
- Iowa Department of Natural Resources
All listed purposes: Recreation;Other.
Source: USACE National Inventory of Dams, NID ID IA01346 · Operator website
EPA Impairment Status
Lower Pine Lake 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 02-IOW-758 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Lower Pine Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger.
- Eldora City Of StpEldora · 0.8 mi away · NPDES IA0025933Major
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 #2 of 2 lakes in Hardin County
Nearby Lakes With Higher Grades
Lower Pine Lake holds Grade F. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Hardin County
Frequently asked questions about Lower Pine Lake
Where is Lower Pine Lake?
- Lower Pine Lake is a lake in Hardin County, Iowa. LakeQuality grades it F for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Lower Pine Lake?
- Lower Pine Lake in Hardin County, Iowa has a water quality grade of F (Algae-prone). Water clarity: 1.3 ft visibility. Phosphorus: 187 µg/L. Chlorophyll-a (algae): 73.5 µg/L. Surface area: 85 acres.
Is Lower Pine Lake safe to swim in?
- Based on E. coli testing, Lower Pine Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 25 samples across 7 seasons. That works out to a bacteria swim-safety grade of A — a historical summary of past testing, not a current reading. Lower Pine Lake has a water quality grade of F (Algae-prone). Bacteria levels can spike quickly after heavy rain, so always check Iowa's current beach and health-department advisories before you swim.
What is the water temperature of Lower Pine Lake?
- Lower Pine Lake typically sits around 72°F at the surface in September, from 38 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
Are there boat ramps on Lower Pine Lake?
- Lower Pine Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Pine Lake State Park, Pine Lake State Park. Public access is listed as yes.
Explore Lower Pine Lake across LakeQuality
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Where this data comes from
102 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_WQX102 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
- 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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Named boat-access points from the USGS National Boat Ramps inventory