Terry Trueblood Lake
Johnson County, IowaView mapDirections
Nutrients and algae run well above the regional average.
- Hypereutrophic
- #3 of 3 in the county
- 18 ft max depth
- Public access
- Limited data
Terry Trueblood Lake in Johnson County, Iowa has a water quality grade of F (Algae-prone). Water clarity: 1.1 ft visibility. Phosphorus: 183 µg/L. Chlorophyll-a (algae): 37.9 µg/L.
- Clarity
- 1.1 ft
- Max depth
- ~18 ft est.
- Type
- Hypereutrophic
- Phosphorus
- 183 µg/L
- Chlorophyll-a
- 37.9 µg/L
- Trend
- ↑ Improving
- Public access
- Yes
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Stays near Terry Trueblood Lake
Compare lakeside cabins, hotels, and vacation rentals near Terry Trueblood Lake in Johnson 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 Terry Trueblood Lake are listed below.
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Watch Terry Trueblood Lake’s letter
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Terry Trueblood Lake is a highly nutrient-loaded hypereutrophic lake in Johnson County, Iowa with an estimated average depth of about 18 feet. 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 1 public boat landing. Compared to the 2 other monitored lakes in Johnson County, Terry Trueblood Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-09-10. Grade methodology: LakeQuality methodology.
What Terry Trueblood Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming Safety
Grade onlyLimited data
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 1.1 ft of visibility. Phosphorus 183 µg/L. Chlorophyll-a 37.9 µg/L. TSI 74. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.1 ft | Not graded |
| Phosphorus | 183 µg/L | Poor |
| Chlorophyll-a (Algae) | 37.9 µg/L | Poor |
| Trophic State Index (TSI) | 74 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~18 ft est. |
| Average Depth | ~7 ft est. |
| Public Access | Yes |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Iowa has not published bathymetry for Terry Trueblood Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
- Terry Trueblood Recreation AreaPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Terry Trueblood Lake
Water Quality Trend: ↑ Improving
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.15 m/yr | 2 |
| Phosphorus | ↑ Improving | -154 µg/L/yr | 2 |
| Chlorophyll-a | ↑ Improving | -291.7 µg/L/yr | 2 |
Regulated Pollution Sources Nearby
21 EPA-permitted facilities operate within about 5 miles of Terry Trueblood Lake under Clean Water Act (NPDES) discharge permits, including 3 classified by the EPA as major dischargers. 11 facilities have a reported Clean Water Act violation in the past three years.
- Iowa City, City Of (South) StpIowa City · 1.6 mi away · NPDES IA0070866MajorRecent violation
- University Of Iowa Power PlantIowa City · 2.4 mi away · NPDES IA0003077MajorRecent violation
- Iowa City, City Of (North) StpIowa City · 1.7 mi away · NPDES IA0042617Major
- Lake RidgeIowa City · 0.9 mi away · NPDES IA0074284Recent violation
- Makada Subdivision-StpIowa City · 1.1 mi away · NPDES IA0073733Recent violation
- Iowa City Regency Mobile Home Park StpIowa City · 1.2 mi away · NPDES IA0063274Recent 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 #3 of 3 lakes in Johnson County
Nearby Lakes With Higher Grades
Terry Trueblood Lake holds Grade F. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in Johnson County
Frequently asked questions about Terry Trueblood Lake
Where is Terry Trueblood Lake?
- Terry Trueblood Lake is a lake in Johnson County, Iowa. LakeQuality grades it F for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Terry Trueblood Lake?
- Terry Trueblood Lake in Johnson County, Iowa has a water quality grade of F (Algae-prone). Water clarity: 1.1 ft visibility. Phosphorus: 183 µg/L. Chlorophyll-a (algae): 37.9 µg/L.
Is Terry Trueblood Lake safe to swim in?
- The F is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
How deep is Terry Trueblood Lake?
- No published bathymetric survey covers Terry Trueblood Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 18 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Are there boat ramps on Terry Trueblood Lake?
- Terry Trueblood Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Terry Trueblood Recreation Area. Public access is listed as yes.
Explore Terry Trueblood Lake across LakeQuality
More Iowa Lake Rankings
Other Grade F Lakes in Iowa
Hypereutrophic Lakes in Iowa
Where this data comes from
29 measurements from 1 monitoring station, 2023–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Iowa DNR Surface Water Monitoring Data
21IOWA_WQX29 samples · 2023–2024
Analytical methods
- Unknown
- Phosphorus by Colorimetry
- 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)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory