How to protect our waters and be septic smart in the Lakes Region

If you own a home with a septic system, one of the most important things you can do to protect our lakes is keep it properly maintained. When working as intended, a septic system partially treats household wastewater in the tank before liquid effluent flows to the drainfield, where additional treatment occurs as it moves through the soil. As systems age or go without proper maintenance, however, they can become a source of nutrients and other pollutants to groundwater and nearby lakes and streams.

You do not have to live directly on the shoreline for your septic system to affect water quality. Groundwater moves beneath the landscape and eventually reaches streams, wetlands, and lakes. Properties close to the water may have less distance and opportunity for soil to filter nutrients before groundwater reaches the lake.

Wastewater contains phosphorus and nitrogen, nutrients that can cause problems when too much reaches our waters. Excess nutrients can fuel the growth of plants, algae, and cyanobacteria, contribute to declining water clarity, and affect aquatic life.

Septic problems are not always obvious. Even without backups, odors, or wet areas in the yard, an aging or damaged system may no longer be treating wastewater effectively.

Several common practices can damage septic systems. Trees, shrubs, and other woody vegetation planted near a system can send roots into pipes, joints, tanks, and leach fields, causing blockages or damage. Keep the area over the tank and leach field in grass or other shallow-rooted vegetation.

Driving or parking vehicles, boats, trailers, or heavy equipment over a septic system can compact soil and damage buried components. Excessive water use and leaking plumbing fixtures can overload a system. Solids that are not removed through regular pumping can eventually reach the leach field, clogging the system and reducing its ability to treat wastewater.

Age can also be a factor as components deteriorate and older systems may no longer perform as effectively as they once did.

Preventative maintenance matters. We recommend pumping septic tanks every two years and having systems inspected every five to seven years, or more frequently depending on age and use. Conserve water, spread high-water-use activities throughout the week, and avoid flushing wipes, grease, chemicals, medications, or other materials that can harm your system.

Waterfront property owners should also know New Hampshire's requirements for property transfers. Since Sept. 1, 2024, state law requires a septic system evaluation before the transfer of qualifying developed waterfront property when any portion of the system is within 250 feet of the reference line of a waterbody protected under the Shoreland Water Quality Protection Act. Additional requirements apply to certain older or unapproved systems.

For those of us who love New Hampshire's lakes, septic care is lake care. Maintaining your system protects your home and investment while reducing the nutrients reaching the waters we all share.

A healthy lake starts on the land around it, and sometimes one of the most important things you can do for the water is right beneath your own backyard.

For more information, visit EPA's SepticSmart program at epa.gov/septic/septicsmart.

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Bree Rossiter is the associate director of the Lake Winnipesaukee Alliance, the only nonprofit dedicated to protecting the water quality and natural resources of Lake Winnipesaukee and its watershed through science, education, advocacy, and collaborative solutions. Her work focuses on advancing long-term watershed protection initiatives and connecting science with practical solutions to help preserve the lake for future generations. To learn more, visit winnipesaukee.org.