Silver Lake
Palo Alto County, IowaView mapDirections
Nutrients and algae run well above the regional average.
- Hypereutrophic
- Impaired · Algal growth
- #2 of 3 in the county
- 51 ft max depth
- Public access
Silver Lake in Palo Alto County, Iowa has a water quality grade of F (Algae-prone). Water clarity: 1.2 ft visibility. Phosphorus: 209 µg/L. Chlorophyll-a (algae): 53.9 µg/L.
- Clarity
- 1.2 ft
- Typical in September
- 70°F
- Max depth
- ~51 ft est.
- Type
- Hypereutrophic
- Trend
- ↓ Declining
- Public access
- Yes
Stays via Stay22
Stays near Silver Lake
Compare lakeside cabins, hotels, and vacation rentals near Silver Lake in Palo Alto 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 Silver Lake are listed below.
Top-rated places to stay near Silver Lake
Prices for Sep 11–13, 4 adults. Change dates on the map below.
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Watch Silver Lake’s letter
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Free interactive depth-contour map of Silver Lake, reaching a maximum surveyed depth of 6 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
Silver Lake is a highly nutrient-loaded hypereutrophic lake in Palo Alto County, Iowa with an estimated average depth of about 51 feet. Water quality is graded F based on 2 sampling years through 2024. Overall water quality is declining 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 Palo Alto County, Silver Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-09-11. Grade methodology: LakeQuality methodology.
What Silver Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
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. Silver Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for algal growth, turbidity. Check local advisories before you swim.
Water Quality Grade: F (Algae-prone)
Very murky, less than 1.2 ft of visibility. Phosphorus 209 µg/L. Chlorophyll-a 53.9 µg/L. TSI 75. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.2 ft | Not graded |
| Phosphorus | 209 µg/L | Poor |
| Chlorophyll-a (Algae) | 53.9 µg/L | Poor |
| Trophic State Index (TSI) | 75 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Water Temperature
Silver Lake typically sits around 70°F at the surface in September. Summer average is about 75°F. Usually warmest in Jul (about 80°F) and coldest in Jun (about 70°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 27 field readings (2010–2023) via the EPA Water Quality Portal. See the full Silver Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~51 ft est. |
| Average Depth | ~9 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 Silver 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
- Silver Lake - Palo AltoPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Silver Lake
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.019 m/yr | 5 |
| Phosphorus | ↓ Declining | +59.3 µg/L/yr | 4 |
| Chlorophyll-a | ↑ Improving | -17.53 µg/L/yr | 5 |
EPA Impairment Status
Silver Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IA 04-UDM-1229 · Official waterbody report
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Silver Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Ayrshire, City Of StpAyrshire · 2.9 mi away · NPDES IA0079677Recent violation
- Ayrshire, City Of WtpAyrshire · 2.5 mi away · NPDES IA0084361
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 3 lakes in Palo Alto County
Nearby Lakes With Higher Grades
Silver 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.
See full comparison →Nearby Lakes in Palo Alto County
Frequently asked questions about Silver Lake
Where is Silver Lake?
- Silver Lake is a lake in Palo Alto County, Iowa. LakeQuality grades it F for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Silver Lake?
- Silver Lake in Palo Alto County, Iowa has a water quality grade of F (Algae-prone). Water clarity: 1.2 ft visibility. Phosphorus: 209 µg/L. Chlorophyll-a (algae): 53.9 µg/L.
Is Silver Lake safe to swim in?
- The F is nutrients and algae, not a swimming clearance. Silver Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for algal growth, turbidity. Check local advisories before you swim.
What is the water temperature of Silver Lake?
- Silver Lake typically sits around 70°F at the surface in September, from 27 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
How deep is Silver Lake?
- No published bathymetric survey covers Silver Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 51 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 Silver Lake?
- Silver Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Silver Lake - Palo Alto. Public access is listed as yes.
Explore Silver Lake across LakeQuality
More Iowa Lake Rankings
Other Grade F Lakes in Iowa
Hypereutrophic Lakes in Iowa
Where this data comes from
52 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_WQX52 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)
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)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory