How to Choose a Lake Property Using Water Quality Data

Start with the Readings

Three numbers on a lake page do most of the work: Secchi clarity, total phosphorus and chlorophyll-a, each shown with the EPA condition class for the lake's ecoregion. Lakes whose phosphorus and chlorophyll-a both read Good, and whose clarity runs deep, are the ones where you can expect clear water for swimming, healthy fisheries, and minimal algae problems during a typical summer.

A lake whose nutrients read Fair is not necessarily a poor choice, many popular recreation lakes do, but you should understand the trade-offs. Expect visible algae during warm periods, swimming that may be unpleasant in late summer, and a property value premium lower than on cleaner lakes. Poor readings on both nutrients and algae indicate water quality problems that are unlikely to resolve without major watershed intervention over many years. For most buyers, focusing on lakes with Good nutrient and algae readings eliminates the risk of purchasing on a lake with chronic water quality issues.

Check the Trend Direction

A lake's current readings are important, but its trajectory may matter even more for a long-term investment. Among lakes with sufficient trend data, approximately 39% are improving, which means water clarity is increasing and nutrient levels are declining over a multi-year period.

An improving lake is increasing in value in multiple ways: the recreational experience is getting better, the ecological health is strengthening, and property values tend to follow water quality improvements. Conversely, a declining lake, even one with good current readings, may indicate problems ahead: increasing development pressure, failing septic systems in the watershed, or agricultural intensification. Always check the trend data on the lake page before making a purchase decision. A lake with mid-range readings and an improving trend is often a better long-term investment than one with the lowest readings and a declining trend.

Evaluate Lake Depth and Physical Characteristics

Lake depth is one of the strongest predictors of long-term water quality stability. Across our dataset, 3,025 lakes exceed 40 feet in maximum depth. Deep lakes are more resistant to water quality degradation for several reasons: their larger water volume dilutes nutrient inputs, cold deep water (hypolimnion) provides refugia for coldwater fish species, and the greater depth reduces the influence of wind-driven sediment resuspension.

Shallow lakes, those under 15 feet maximum depth, are inherently more volatile. Wind can stir bottom sediments and release nutrients throughout the water column, winter ice cover can deplete dissolved oxygen and cause fish kills, and warm summer temperatures affect the entire water volume rather than just a thin surface layer. If water quality stability is your priority, favor lakes with at least 30 to 40 feet of maximum depth.

Lake surface area matters too, but in different ways. Large lakes offer more recreation space and longer sightlines, but they also attract more boat traffic and development pressure. Smaller lakes (100 to 500 acres) often maintain better water quality due to lower watershed-to-lake ratios and less intensive shoreline development.

Look at the Fishery

Fish species composition tells you a great deal about a lake's ecological health and the activities you will enjoy. Lakes supporting coldwater species, lake trout, cisco (tullibee), and whitefish, have the best water quality, deepest water, and highest dissolved oxygen levels. These are almost exclusively lakes with the lowest nutrient and algae readings.

Lakes with strong walleye populations typically have Good nutrient and algae readings, moderate to high clarity, and diverse structure. Walleye lakes are among the most sought-after in Minnesota and command premium property values. Bass lakes span a wider quality range, excellent smallmouth bass fisheries tend to occur in clear, rocky, low-nutrient lakes, while largemouth bass thrive in moderate-nutrient lakes with abundant vegetation.

If the lake's fish species list is dominated by rough fish, common carp, bullheads, and buffalo, this is a strong indicator of degraded water quality regardless of the current readings. Rough fish dominance suggests the lake has experienced significant ecological changes and may be difficult to restore.

Investigate Invasive Species

Before purchasing on any lake, check the LakeQuality invasive species data and the Minnesota DNR or Wisconsin DNR infested waters lists. Zebra mussels, Eurasian watermilfoil, and starry stonewort can dramatically alter a lake's character, affecting boating, swimming, shoreline aesthetics, and maintenance costs. While invasive species do not necessarily reduce water quality (zebra mussels actually increase clarity in many lakes), they change the recreational experience and can increase maintenance costs for docks, lifts, and water intakes.

Lakes without invasive species are increasingly rare and increasingly valuable. If invasive-free status is important to you, prioritize lakes with active AIS prevention programs, decontamination stations at public accesses, and engaged lake associations that fund boat inspection programs.

Assess the Watershed and Community

The land surrounding a lake determines its future water quality. Review the LakeQuality county and watershed data to understand what land uses dominate the area. Lakes surrounded by forest and wetlands have the most stable water quality. Lakes in agricultural watersheds face ongoing nutrient pressure that can be difficult to manage. Lakes in rapidly developing suburban areas face increasing stormwater and septic system impacts.

Just as important as the physical watershed is the human community. Lakes with active, well-funded lake associations and lake improvement districts have consistently better outcomes than similar lakes without organized management. Ask whether the lake has a current lake management plan, regular water quality monitoring, and an engaged group of property owners committed to long-term stewardship.

Deep, Low-Nutrient Lakes with a Documented Fishery

These lakes combine the lowest nutrient and algae readings for their ecoregion, depth exceeding 30 feet, and at least three documented fish species, the characteristics most associated with strong long-term property value and recreational quality:

Note: this list is limited to states with lake-depth and fish-survey data, currently Minnesota and Wisconsin.

Frequently Asked Questions