Skip to main content
LakeQuality

Preston Lake

F
Grade F — Algae-prone
Algae-prone · #2 of 2 lakes in the county · 5 ft clear · Eutrophic · 655 acres · from D
Eutrophic

Preston Lake in Renville County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 5 ft visibility. Phosphorus: 222 µg/L. Chlorophyll-a (algae): 39.2 µg/L. Maximum depth: 11 ft. Surface area: 654.96 acres.

Clarity
5 ft
Typical in July
80°F
Max depth
11 ft
Area
655 acres
Type
Eutrophic
Trend
Improving
Public access
Yes
Ice-out
Apr 16

Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Preston Lake

Next lake in Renville County

CAllie Lake3 ft clear · Renville CountyView →
Loading map…

Preston Lake is a 655-acre productive, nutrient-rich eutrophic lake in Renville County, Minnesota with a maximum depth of 11 feet (7-foot average). Water quality is graded F based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 13 documented fish species including bigmouth buffalo, black bullhead, and black crappie. Public access is available with 1 public boat landing. Compared to the 1 other monitored lakes in Renville County, Preston Lake ranks #2 for water quality.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-15. Grade methodology: LakeGrade methodology.

Watch Preston Lake water quality

Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.

Swimming Safety

Grade only

Algae 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.

Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom

Compare the safest swimming lakes near Willmar

Get alerts for Preston Lake

Water Quality Grade: F (Algae-prone)

Murky, only visible to about 5 ft. Phosphorus level: 222 µg/L. Chlorophyll-a: 39.2 µg/L. Trophic State Index: 68.

MetricValueGrade
Water Clarity (Secchi Depth)5 ftNot graded
Phosphorus222 µg/LPoor
Chlorophyll-a (Algae)39.2 µg/LPoor
Trophic State Index (TSI)68Eutrophic

High nutrients, frequent algae, reduced clarity

Where to stay near Preston Lake

Compare lakeside cabins, hotels, and vacation rentals near Preston Lake in Renville County, Minnesota — 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 Preston Lake are listed below.

Top-rated places to stay near Preston Lake

Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.

Planning a whole trip? See where to stay at Minnesota’s top lakes →

Water Temperature

Preston Lake typically sits around 80°F at the surface in July. Summer average is about 73°F. Usually warmest in Jul (about 80°F) and coldest in Jun (about 65°F). These are typical values by month — not a live reading.

Jan
Feb
Mar
Apr
May
Jun
65°
Jul
80°
Aug
Sep
70°
Oct
Nov
Dec

Typical surface water temperature by month, from 8 field readings (20162025) via the EPA Water Quality Portal. See the full Preston Lake water temperature breakdown →

Lake Details

CharacteristicValue
Maximum Depth11 ft
Average Depth7 ft
Surface Area655 acres
Shoreline Length5.4 mi
Littoral Zone100%
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
7 sq mi
Elevation
1,033 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).

Recreation & Access

1
Boat Landings
Yes
Public Access
  • Preston LakePublic

Fish Species

Click a species to see every graded lake where it is documented.

Fishing Preston Lake

DNR Fisheries Survey Summary

13 surveys on file from MN DNR Fisheries. Most recent: 2025-07-07 (Targeted Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Black Bullhead82.530.26 lb
Common Carp21.314.9 lb
Brown Bullhead19.290.79 lb
CRP15.74
Fathead Minnow13.41
Walleye12.861.36 lb

CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.

Length Distributions

Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.

Black Bullhead

3 fish · 59 in · 2025-07-07
1056789

Common Carp

12 fish · 2229 in · 2025-07-07
4202223242526272829

Brown Bullhead

2 fish · 1212 in · 2010-07-26
21012

Walleye

32 fish · 1027 in · 2025-07-07
1260trophy 24101214161820222426

From the 2025-07-07 survey

Preston is a moderate-sized lake (655 acres) located northeast of the Town of Buffalo Lake in Renville County. A state-owned access with gravel parking and a single cement boat ramp is present along the west shore. There is a fishing pier present at the public access. Preston has approximately five miles of shoreline…

Source: MN DNR LakeFinder Fisheries Lake Survey

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Preston Lake. 3 reports on file.

These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).

Based on 6 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.057 m/yr5
Phosphorus Improving-10.23 µg/L/yr6
Chlorophyll-a Declining+2.11 µg/L/yr6
See year-by-year chart →

Ice Season

Historical ice data from Minnesota DNR (6 observations).

Typical Ice-Out
Apr 16
EarliestLatest
Ice-Out2017-03-06 (2017)2018-05-01 (2018)
Ice-In2014-11-16 (2014)2013-12-01 (2013)

Most recent ice-out: 2018-05-01

EPA Impairment Status

Preston Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).

Causes of impairment

MercuryNutrients (phosphorus, nitrogen)

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MN65-0002-00 · Official waterbody report

County Ranking

Ranked #2 of 2 lakes in Renville County

Nearby Lakes With Higher Grades

Preston Lake holds Grade F. 2 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 Renville County

Frequently asked questions about Preston Lake

What is the water quality grade for Preston Lake?

Preston Lake in Renville County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 5 ft visibility. Phosphorus: 222 µg/L. Chlorophyll-a (algae): 39.2 µg/L. Maximum depth: 11 ft. Surface area: 654.96 acres.

Is Preston Lake safe to swim in?

Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. Preston Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 39.2 µg/L. Always check local health department advisories before swimming.

What is the water temperature of Preston Lake?

Preston Lake typically sits around 80°F at the surface in July, from 8 EPA Water Quality Portal field readings (2016–2025). That is a typical value for the month, not a live reading.

How deep is Preston Lake?

Preston Lake has a maximum depth of 11 feet and an average depth of 7 feet. The lake covers 654.96 acres.

What fish are in Preston Lake?

Fish species found in Preston Lake include bigmouth buffalo, black bullhead, black crappie, bluegill, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, orangespotted sunfish, walleye, white sucker, yellow perch. Preston Lake is located in Renville County, Minnesota.

When does Preston Lake thaw?

Preston Lake typically has ice-out around Apr 16.

Are there boat ramps on Preston Lake?

Preston Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Preston Lake. Public access is listed as yes.

Where this data comes from

69 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Minnesota Pollution Control Agency - Ambient Surface WaterMNPCA69 samples · 2020–2025

Analytical methods

  • Field measurement/observation, generic method
  • Phosphorus by Colorimetry
  • 10200 H ~ Chlorophyll a-b-c Determination
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

Lake size & watershed from HydroLAKES (HydroSHEDS)

Lake details from Minnesota DNR LakeFinder

Named boat-access points from the USGS National Boat Ramps inventory

Ice data from Minnesota DNR Climate