Septic Systems


Good septic systems are key to healthy lakes

The state of septic systems around our shores is a key factor affecting water quality in our lakes.

Pollution from faulty septic systems contributes to high levels of phosphorus, excessive algae and weed growth, and bacteria levels in water.

That’s why Environment Council has been working for years to raise awareness among local governments and waterfront owners about the importance of good septic system practices. 

Based on what we’ve learned from other jurisdictions in Ontario since 2010, there’s little doubt that old and inadequate septic systems, holding tanks and privies are polluting our lakes.

As our Septic Task Team explained in a presentation to Douro-Dummer Township Council, improperly maintained septics have been identified as one of the greatest threats to water quality. And good water quality is key to the positive recreational and economic contribution that our lakes make to local businesses and the townships.

Failed or damaged septic systems can contaminate soil, groundwater and wells. And improperly maintained septics contribute to nutrient and bacterial pollution in nearby water bodies. In short, pollution from septics leaches into streams and lakes and damages them.


Faulty septics affect health

As a result, faulty septic systems pose a threat to human health. Nitrates from faulty septics can contaminate the surrounding soil and penetrate hundreds of feet into groundwater. This is a concern to human (and animal) health because nitrates can interfere with the body’s ability to carry oxygen.

Phosphorus and nitrogen from septics also cause excessive growth of aquatic weeds and algae, including the dangerous blue-green variety.

Overly abundant weeds and algae detract from our enjoyment of the lakes. More importantly, blue-green algae affects virtually all uses of lake water and can cause serious illness. To learn more about blue-green algae, go to Water Quality on the menu bar, and click on Algae.

In addition, bacterial contamination from septics can cause a number of illnesses. Swimming or playing water sports in contaminated lake water can result in eye infections, dysentery or hepatitis.

The Environ


Many septic systems need repair or replacement

James Wilkes

Over the last few years, our Septic Task Team has reviewed the results of many other re-inspection programs – particularly those in “cottage country”.

These results show that about five percent of systems re-inspected need to have the septic tank and field replaced, and 20 to 30 percent need to be pumped and/or repaired.

Since our lakes have so many older cottages, islands and water access only properties, many septics and holding tanks (not to mention privies) may be older than average. This raises the possibility that the number of faulty septics on our lakes may be at the high end of the range found in other locations.

Septic systems can falter or fail for many reasons – improper design or construction, or improper use and maintenance.

Systems may become overloaded because they are too small or haven’t been pumped, may corrode and leak, have worn or missing baffles, become clogged with tree roots, compacted by vehicles, or malfunction because of foreign objects or chemicals put down the drain.

For quick tips on how to take care of your septic system, click on Septic Tips on the menu bar.

For more detailed information on septic systems, go to or

Earlier work set the stage

During the Lake Planning process in 2005-2008, septic systems were identified as an important factor in lake water quality. Then in 2010, a number of our members became increasingly concerned that old and faulty septics were polluting our lakes.

These members formed a task team to further study how septic systems affect water quality and to find out what other jurisdictions in Ontario were doing with regard to septic re-inspection programs.

The study team also reviewed relevant research and legislation and consulted with the (then) Peterborough County-City Health Unit and the County Planning Department.

Recognizing that under the Ontario Building Code, municipalities are responsible for septic re-inspection, we presented our findings to the four townships surrounding our lakes in a series of workshops in 2012 and 2013.

We asked that they consider a planned program of septic re-inspections for all septics and holding tanks in each municipality, working with the Health Unit.

The idea was well received by the Townships but, because they needed to focus first on the Source Water Protection Program, no decisions were made on timing.

North Kawartha Township launched its own re-inspection program in 2014, using summer students to carry out about 600 inspections a year.

Re-inspections are starting on the North Kawartha shore and islands of Ston(e)y Lake in Spring of 2018.

In 2016, Trent Lakes started its program in co-operation with Peterborough Public Health (PPH).

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