H. Septic Systems In Lake Watersheds

Afternoon Session – 1:30PM-4:00PM
Piscataquis/Sagadahoc Room (2nd floor)

Session Co-Chairs:

Watershed management requires identifying and addressing all sources of nonpoint source pollution and then taking actions to address it. Septic systems remain an elusive source that may be contributing more to the problem than we think and posing an often-overlooked threat to Maine’s freshwater lakes. For lake managers, it has historically been difficult to assess the nutrient contribution from septic systems. Some reasons for this include: once installed they are out-of-sight and out-of-mind, lack of documentation – especially for older systems, lack of landowner knowledge about system function and their responsibilities, lack of landowner participation/cooperation with voluntary assessment efforts, and the sheer number of systems and variations in site conditions that make it challenging for those without extensive knowledge to evaluate. Instances where systems were built on soils that make them vulnerable to “short-circuiting” to groundwater and surface water or were installed prior to the current state plumbing code are particularly important to scrutinize, because they have the greatest potential impact to lakes. The focus of this session is to present a broad range of projects that aim to trace, track, model, and fix septic systems in lake watersheds across the state.

Session Overview

Session Abstracts

Presenters are indicated in bold font.

Is Your Septic System an Asset or a Detriment to Lake Water Quality?

A pdf of this presentation is available. Please contact David Rocque with any questions.

David Rocque
Consulting Soil Scientist & Site Evaluator

For good reason, the focus, both nationally and here in Maine, on the disposal of human waste water has been human health, not environmental impacts. It has long been understood that people not only get sick but die when they come in contact with raw human waste water. It has also been well understood that infiltrating human waste water into the soil is an excellent way to renovate it and thereby prevent people from getting sick and/or dying. Over time, environmental concerns have been incorporated into on-site septic system designs providing for better treatment of the waste water and better protection of natural resources. There are still however, additional improvements needed, particularly regarding the protection of lake water quality. This talk will focus on the short comings of the septic system designs in Maine that may lead to lake water quality degradation.

Opening a Can of Worms: Septic System Inspections and Biomat Evaluations in the Georges Pond Watershed

A pdf of this presentation is available. Please contact Jennifer Jespersen with any questions.

Jennifer Jespersen1, David Rocque2, John Eliasberg3
1. Ecological Instincts
2. Consulting Soil Scientist & Site Evaluator
3. Georges Pond Association

Georges Pond is a 358-acre lake with a 1-square mile watershed located in Franklin, ME. The lake is listed on Maine’s nonpoint source (NPS) priority watersheds list due to changes in water quality over the past decade- specifically because of nuisance algal blooms which began in 2012. The Georges Pond Association developed a Watershed-Based Management Plan in 2020 that provided a 10-year strategy for reducing phosphorus (P) from the lake and watershed by addressing internal loading and increasing efforts to mitigate NPS pollution. The plan included a septic system vulnerability analysis which identified 102 “at risk” shoreline properties on soils susceptible to septic system short-circuiting, In 2021, GPA received a Section 319, Phase II Watershed Protection grant which included septic system inspections and biomat evaluations for five at-risk septic systems to determine if a “short-circuit” was occurring at no cost to participating landowners. Five biomat evaluations and septic system inspections were conducted over a two-day period in the summer of 2022. As expected, results of these evaluations showed that the two pre-1974 systems were non-functional and a threat to Georges Pond’s water quality. Surprisingly, two of the three post-1974 systems were, in fact, more of a threat to the water quality of Georges Pond than the pre-1974 systems. The results of these field investigations raise concern about the ability of older (pre-1995) septic systems to treat P and prevent it from getting into the lake via groundwater or other means when located on course sandy soils.

Afternoon Break

Exploring the use of fluorescent whitening compounds as tracers of septic system effluent in Maine lakes

A pdf of this presentation is available. Please contact Ben Peierls with any questions.

Benjamin Peierls
Lakes Environmental Association

Septic systems within lake watersheds have the potential to contribute excess nutrients and microbial pathogens to local water bodies if not functioning or maintained properly. Tracing malfunctioning septic systems by detecting effluent in stream or lake water can be challenging and requires a measurable human-specific marker. Fecal indicator bacteria are commonly used, but these general indicators are not specific to human waste. A range of biological and chemical methods for identifying human waste exist, although the expense and expertise requirements for some analyses can be prohibitive. One relatively low-cost chemical method is the measurement of fluorescent whitening compounds (FWC), which are used as optical brighteners in laundry detergents and paper products. Despite FWC adsorbing to fabrics and soils, enough remains in wastewater effluent to reach lakes and streams, where it can be measured by UV-induced fluorescence; FWC presence would indicate failing septic systems in the vicinity. Natural organic matter fluorescence does interfere with that of FWC, but newer methods use differences in photodecay rates to correct for this. We tested a variation of this method on volunteer-collected littoral water samples from lakes in the Greater Sebago Lake Region. Out of almost 200 samples collected on 9 different lakes during two busy summer periods, about 37% tested positive for FWC. This suggests that septic system effluent was present in at least some of the samples, though this has not been confirmed through other methods. Further work is needed to address detection limits and high replicate variability.

Using caffeine as a tracer for septic contamination in lakes: a pilot study on North Pond

A pdf of this presentation is available. Please contact Brian DiMento with any questions.

Brian DiMento1, Whitney King1, Danielle Wain2, Claire Yu1, Margo Kenyon1, Julie Millard1, Charlie Baeder2
1. Colby College
2. 7 Lakes Alliance

North Pond (Smithfield, ME) has been experiencing severe cyanobacterial blooms since 2018. The lake watershed has regions of sandy soils and camps that have septic systems closer to the lake than would now be permitted. For this reason, it is hypothesized that the contribution of septic systems to the phosphorus load in the lake might be higher than estimated for neighboring watersheds. In Summer 2022, we conducted pilot experiments to determine if caffeine could be used as a tracer for septic contamination. Caffeine was analyzed using ELISA assays with detection limits of 0.2 ppb which should make caffeine inputs from failed septic systems detectable. After compiling available geological and septic information, water samples were taken at targeted shoreline locations on North Pond to determine if patterns in caffeine could be observed. While initial results are inconclusive, caffeine was detected in several locations, showing that this technique may provide useful information for lake management.

Panel Discussion

This panel discussion will feature experts involved in various aspects of subsurface wastewater disposal in Maine, including state and municipal staff. The panel will answer audience questions on topics related to septic system design, installation and inspection, funding opportunities for system replacement, subsurface wastewater rules, and considerations to keep in mind when managing systems near waterbodies.


  • Alex Pugh, Sr. Environmental Hydrogeologist, Maine Center for Disease Control & Prevention
  • Robert Hartley, Senior Environmental Engineer, Small Community Grants Program Coordinator, Division of Water Quality Management, Maine Dept. of Environmental Protection
  • Andrew Marble, Rome Code Officer & LPI, Town of Rome, ME
  • David Rocque, Consulting Soil Scientist & Site Evaluator

About Our Session Chairs

Amanda Pratt is a Water Resources Specialist at Portland Water District. Her work focuses on drinking water source protection in the Sebago Lake watershed. Her previous experience includes water quality monitoring, watershed planning, and nonpoint source pollution abatement on a variety of lakes throughout Maine, first at Lakes Environmental Association and more recently at Maine Department of Environmental Protection. She has a Bachelor’s degree in Environmental Science from the University of Southern Maine and a Master’s degree in Watershed Management from the University of Stirling.

Jen Jespersen is the owner and Senior Scientist at Ecological Instincts, a small, Maine-based, women-owned environmental consulting firm based in Manchester. Her expertise is in assisting municipalities, lake associations, and watershed groups with water quality monitoring, watershed assessments, watershed management planning, grant writing, and project management for watershed restoration projects statewide. She has a Bachelor’s degree in Interdisciplinary Environmental Science from the University of Maine at Farmington, and a Master’s degree in Ecology and Environmental Science from the University of Maine. Jen currently serves on the Advisory Board for Maine Lakes.