Polluted Runoff Water

Polluted Runoff Water

As New Hampshire’s forested land is cleared for homes, businesses, roadways, and parking lots, the natural ability of the landscape to soak up melted snow and rain water decreases. Because of this, more runoff water travels across pavement and lawns, picking up pollutants on the way into our lakes.


The water quality of a lake is primarily determined by what flows into it from the surrounding landscape (the watershed).


Common pollutants in runoff water include fertilizer, road salt, animal waste, and soil. Once in the lake, these pollutants degrade the health of the lake in many ways.

Over ninety percent of the water quality problems in New Hampshire’s lakes and rivers are caused by polluted runoff water.

Watershed Pollution Types

Other Threats to Water Quality

Cyanobacteria

New Hampshire’s lakes have seen a record number of toxic cyanobacteria blooms for the past three summers. These blooms can produce toxins that make people, pets, and wildlife sick.

Climate Change

Invasive species are organisms that thrive in an area where they did not naturally develop and that cause harm to the economy, environment, or people. Learn more about the species we are most concerned about and what you can do to prevent them!

nh lakes flooding