Rathbun Lake
Appanoose County, Iowa11,013 acresView mapDirections
Iowa DNR publishes the water-quality measurements for Rathbun Lake. Here is what has been measured.
- Eutrophic
- Public access
Rathbun Lake in Appanoose County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 3 ft visibility. Phosphorus: 48 µg/L. Chlorophyll-a (algae): 15.3 µg/L. Surface area: 11013 acres.
Rathbun Lake is a 11,013-acre productive, nutrient-rich eutrophic lake in Appanoose County, Iowa. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 6 public boat landings.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-09-17. Methodology: how these readings are compared.
At about 11,000 acres, Rathbun Lake is large enough that where you stay decides which shore you see most of. It has 6 public boat landings, so a lakefront rental is not the only way to get a boat on the water. For a place on the water, look through cabin and lake-house rentals near Rathbun Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
What Rathbun Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch6 documented ramps
- Camping1 public campground nearby
- Big water11,013 acres
Rathbun Lake Water Quality Summary (2026)
A printable one-page summary for Rathbun Lake: clarity, phosphorus, algae, multi-year trend, depth, and fish — with sources.
Swimming conditions
Readings onlyBacteria tested: low
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.
Based on E. coli testing, Rathbun Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 6 samples across 2 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.
Whether Rathbun 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 Rathbun Lake
These are the measurements Iowa DNR publishes for Rathbun Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 3 ft of visibility. Phosphorus 48 µg/L. Chlorophyll-a 15.3 µg/L. TSI 60.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 48µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 15.3µg/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. | 60 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Rathbun Lake
Answers come straight from the public measurements and survey records on this page.
Current Conditions
USGS snapshot Jul 6, 2026, 4:45 AM from gauge 06903880 (Rathbun Lake Near Rathbun, IA). Station page ↗ — a live reading replaces this snapshot when the gauge responds. Missing live data is not an all-clear.
→ Rathbun Lake water level: the live USGS gauge reading
Water Temperature
Rathbun Lake typically sits around 77°F at the surface in September. Summer average is about 76°F. Usually warmest in Jul (about 79°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 (79°F).
Typical surface water temperature by month, from 26 field readings (2010–2023) via the EPA Water Quality Portal. See the full Rathbun Lake water temperature breakdown →
Lake Details
Surface area
11,013 acres
Public access
Yes
Listed by Iowa DNR
No bathymetric survey has been published for Rathbun Lake, so its depth is not documented here.
Recreation & Access
- Sharon Bluffs State ParkPublic
- Outlet ParkPublic
- Rathbun Wildlife Management AreaPublic
- Rathbun Wildlife Management AreaPublic
- Rathbun Wildlife Management AreaPublic
- Rathbun Wildlife Management AreaPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Public campgrounds near Rathbun Lake
- Island View (rathbun Lake)2.2 kmReserve
Nearest public campgrounds in the USGS National Map inventory, within about 3 miles. An empty list means USGS records no campground that close, which is not the same as camping being unavailable. Where the source gives an official reservation link, it is used; the cabin and hotel search does not cover campsites. More camping lakes
Stays via Stay22
Stays near Rathbun Lake
Compare lakeside cabins, hotels, and vacation rentals near Rathbun Lake in Appanoose 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 Rathbun Lake
Prices for Oct 23–25, 4 adults. Change dates on the map below.
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Planning a trip? Cabins and lodging at Rathbun Lake → · more Iowa lake trips
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Fishing Rathbun Lake
Water Quality Trend: Worsening
Based on 4 years of monitoring (2021–2024).
Water clarity
Improving4 years
Phosphorus
Worsening+5.75 µg/L/yr4 years
Chlorophyll-a
Worsening+3.62 µg/L/yr4 years
Reservoir Info (USACE NID)
Rathbun Lake is a man-made reservoir impounded by the Rathbun Dam (completed 1969), built primarily for flood risk reduction on the CHARITON RIVER; earth-type dam, 100 ft tall and 10,120 ft long.
- Surface area
- 11,013 ac
- Normal storage
- 205,359 ac-ft
- Max storage
- 552,000 ac-ft
- Drainage area
- 549 sq mi
- Hazard class
- High
- Owner
- USACE - Kansas City District
All listed purposes: Flood Risk Reduction;Other;Navigation;Fish and Wildlife Pond;Recreation.
Source: USACE National Inventory of Dams, NID ID IA00016 · Operator website
Regulated Pollution Sources Nearby
4 EPA-permitted facilities operate within about 5 miles of Rathbun Lake under Clean Water Act (NPDES) discharge permits. 4 facilities have a reported Clean Water Act violation in the past three years.
- Rathbun Regional Water AssociationCenterville · 0.6 mi away · NPDES IA0075418Recent violation
- Dnr Rathbun Fish HatcheryMoravia · 0.7 mi away · NPDES IA0054844Recent violation
- Parkside Knolls HoaMoravia · 3.9 mi away · NPDES IA0053188Recent violation
- Mystic City Of StpMystic · 4.3 mi away · NPDES IA0071064Recent 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 Appanoose County
Frequently asked questions about Rathbun Lake
Where is Rathbun Lake?
- Rathbun Lake is a lake in Appanoose County, Iowa. Its water-quality measurements are published by Iowa DNR and shown on this page as reported.
What is the water quality of Rathbun Lake?
- Rathbun Lake in Appanoose County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 3 ft visibility. Phosphorus: 48 µg/L. Chlorophyll-a (algae): 15.3 µg/L. Surface area: 11013 acres.
Is Rathbun Lake safe to swim in?
- Based on E. coli testing, Rathbun Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 6 samples across 2 seasons. That is a historical summary of past bacteria testing, not a current reading and not a swimming clearance. Bacteria levels can spike quickly after heavy rain, so whether Rathbun Lake is safe to swim in today is a call for Iowa's water agency and the county health department; check their current beach advisories before you swim.
What is the water temperature of Rathbun Lake?
- Rathbun Lake typically sits around 77°F at the surface in September, from 26 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
What is the water level at Rathbun Lake?
- The USGS snapshot on this page for Rathbun Lake is 906.3 ft of gage height, recorded Jul 6, 2026, 4:45 AM at gauge 06903880. Current Conditions hydrates a live NWIS reading from that same station when the gauge responds. A missed live fetch is not an all-clear.
Are there boat ramps on Rathbun Lake?
- Rathbun Lake has 6 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Sharon Bluffs State Park, Outlet Park, Rathbun Wildlife Management Area, Rathbun Wildlife Management Area, among others. Public access is listed as yes.
Can I fish at Rathbun Lake?
- Rathbun Lake has 6 documented boat landings in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Iowa's fish and wildlife agency, so check its current regulations before you go.
Are there campgrounds on Rathbun Lake?
- Rathbun Lake has 1 public campground from USGS The National Map within 5 km, including Island View (rathbun Lake). This is a location join, not a booking. Cabins and hotels are listed separately; campsite reservations use the official link when the source provides one.
Explore Rathbun 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
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Where this data comes from
51 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_WQX51 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)
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)
Named boat-access points from the USGS National Boat Ramps inventory
Public campgrounds from USGS The National Map Structures, within about 3 miles