The 2025 State of the Great Lakes Report gives water leaders a useful kind of news: progress is real, but it is mixed.

Prepared by Canada and the United States under the Great Lakes Water Quality Agreement, the report assesses the Great Lakes overall as fair, with an unchanging trend. That is not a failing grade. It is also not a reason to ease up.

Behind the assessment is a large body of long-term science. The report draws on nine indicators and 42 sub-indicators, tracking conditions ranging from drinking water, beaches, and fish consumption to toxic chemicals, nutrients, invasive species, habitat, food webs, groundwater, and climate-related change.

Some results show what sustained action can achieve. Mercury concentrations in lake trout fillets have declined substantially since the 1970s and 1980s. The rate of new non-native aquatic species entering the Great Lakes has also slowed. Those gains reflect decades of regulation, cleanup, monitoring, and cross-border cooperation.

But the lakes are not all telling the same story. Established invasive species continue to alter food webs. Nutrient pressures remain persistent, especially in Lake Erie, where harmful and nuisance algal blooms continue to affect the lake’s health. Climate change is adding another layer of stress through warmer waters, less ice cover, stronger storms, and more variable water levels.

That mix of progress and pressure is the point. A stable overall trend can hide important differences between lakes, between nearshore and offshore waters, and between issues that are improving and those that are not.

The report does not point to one simple fix. It points to the work ahead: sustained, practical, lake-by-lake action grounded in science and shaped by the people who know these waters best.