Septic System Maintenance
One of many factors affecting the quality of Lake Leelanau’s water is good stewardship by riparian property owners, which includes maintenance of their septic systems in good condition.
Watch this video Flushing the Future – The Challenge of Failing Septic Systems produced by the Land Information Access Association (LIAA) to learn about the importance of regular pumping and periodic inspection of riparian septic systems.
For additional guidance, check out EGLE's SepticSmart page.
For tips on landscaping over your septic system, see this Michigan State University article.
2025 Study of Water Quality Trends
With the help of the Leelanau Conservancy, water quality samples have been taken the same way in Lake Leelanau for the past 34 years. In the spring of 2025, the Lake Leelanau Lake Association engaged Grand Valley State University to take a deep dive into these data to look for long-term trends and highlight areas for closer monitoring. Here is the report.
Water Quality Trends in North and South Lake Leelanau, 1990-2024.
Water Quality Trends in North and South Lake Leelanau, 1990-2024. (summary page)
Water Quality Reports
The Michigan Clean Water Corps publishes yearly water quality reports for Lakes in Michigan. Here are the recent reports for North and South Lake Leelanau:
2019 Data Report for South Lake Leelanau
2019 Data Report for North Lake Leelanau
2017 Data Report for South Lake Leelanau
2017 Data Report for North Lake Leelanau
Other lake reports are available here.