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Healthy Shorelines for Healthy Lakes

Septic Systems

How Do Septic Systems Affect the Health of Your Lake?

In areas near shorelines it is particularly important to maintain your septic system properly because soil and water conditions near the shore may make the system less efficient in treating wastewater. Incomplete treatment can result in health risks and water quality problems that affect you, your property value and wildlife.

Health risks are the most serious concern related to failing septic systems. Hepatitis, dysentery and other diseases are spread by bacteria, viruses and parasites in wastewater. These disease-causing organisms, called pathogens, could make near-shore water unsafe for recreation.

Inadequate treatment also allows excess nutrients to reach your lake or stream, promoting algae or weed growth.  Algal blooms and abundant weeds not only make the lake unpleasant for swimming and boating, but they also affect water quality for fish and wildlife habitat.

If too many solids escape from the tank to the drain field, the entire system will ultimately clog up.

There are several types of septic tanks – including steel, concrete, plastic or fibreglass – each with their own benefits and limitations.  If you do not know what type of septic tank you have you should find out and have it inspected for decay. If you have a steel tank, you should replace it as soon as possible.

How a Septic System Works

Diagram of septic system

Step 1: Raw sewage and grey water (water from laundry, showers and dishwashing) moves from your house or cottage into the septic tank.
Steps 2 & 3: In the tank, the sewage flows through a series of chambers, where it separates into solid portions, which remain in the tank to break down, and liquid portions (effluent), which move to the drain field. Beneficial bacteria work to break down the solid portions (known as the scum and sludge layers).
Step 4: The partially treated effluent leaves the septic tank when new wastewater flows into the tank.
Step 5: The effluent moves through a distribution system to the drain field.
Step 6: The effluent reaches the drain field and flows through a series of perforated pipes.
Step 7: Some of the effluent is drawn upward and is absorbed by the vegetation covering the drain field.  Gravity then carries the rest into the soils, which filter the remaining pollutants from the effluent.  Bacteria found in the soil then breaks down the toxins remaining in the effluent. The effluent travels down from the soil until it reaches the groundwater and is reconnected with the water cycle.

Approval Process

If you are planning to install or replace a septic system, it must meet requirements outlined in the Ontario Building Code, and an approval from your health unit or municipality must be obtained prior to the installation of the system. Once completed, the system must be inspected before filling takes place. Refer to the Contact List for information on how to contact your municipality or health unit.

How to Maintain Your System and Avoid Problems and Dangers  

The maintenance and care of your septic system is your responsibility. If a septic system is not properly maintained, it is more susceptible to malfunction. The wastewater from a failing septic system can contaminate your well, your neighbour’s well and the shoreline. If you notice a problem, deal with it right away.

It is important to be familiar with your system. You need to know where the tank and drain field are and what type of a system it is. Keep a written history of when it was installed, pumped, inspected, etc.
Aside from knowing your system, there are five main things you can do to properly maintain it:

Someone pumping out a septic system

1. Regular Pump-Outs
The easiest and most important thing is to have the tank pumped out on a regular basis. The majority of system failures occur because the tank wasn’t pumped often enough. Depending on the use and size of your septic system you should have your system pumped every three to five years.

2. Regular Inspections
It is important to inspect a septic system regularly. A good opportunity is when the tank is being pumped out.  At this point you should take the opportunity to
•    Check the scum and sludge depth
•    Inspect the structure of the tank and baffles, looking for any large cracks or deterioration
•    Check the fit of the access lids and arrange for repairs as necessary
•    Listen for water running into the tank once it’s been emptied. Excess water causes excess strain on your drain field.
If you are unable to inspect your septic system yourself, hire a professional such as a septic inspector, a licensed contractor who installs or repairs septic systems, or a representative of a firm that pumps out septic tanks.

3. Protect the Drain Field
The drain field is a sensitive area of the septic system. The breakdown process in this area involves both bacteria and soil. When these components are compromised or removed, the system does not completely treat the wastewater running through it.

You need to
•    Avoid compacting the soils or damaging the distribution pipes in the drain field by keeping heavy machinery (like cars) and heavy foot traffic off the drain field. Compacting the soil can crack the distribution pipes, which causes greater volumes of effluent to be released into the drain field, saturating and ultimately clogging it
•    Avoid watering your lawn over the drain field to keep your system working properly
•    Keep trees away from the septic system, especially ones with creeping roots such as willow, birch, poplar and cedar. It is recommended that a 5 metre perimeter around the edge of the drain field be kept clear of trees and shrubs (at least 10 metres for poplar and willow trees). Ensure there is a vegetated buffer between your drain field and lake or stream.

4. Control Inputs
To reduce stress on the septic system and the environment, control the amount of liquids and solids put into the system. It is recommended that you
•    Install water-saving devices (i.e., water-saving taps, showerheads, toilets and appliances)
•    Practice-water saving techniques: don’t leave the tap running; fix leaky taps or running toilets; use dishwashers and washing machines only when they are full and spread loads out over the week
•    Avoid using commercial cleaners and opt for more environmentally friendly alternatives.  Chemical cleaners, solvents, antifreeze and cigarette butts all kill the beneficial bacteria in a septic system. Reduce the amount of solids that have to be broken down. A good rule to follow is, “If you didn’t produce it, it shouldn’t be going down your system.”
•    Avoid using septic additives as they are not effective and may harm your system

Photo of an effluent filter

5. Add an effluent filter.
Effluent filters are strainers installed in the outlet pipe from the tank. They are strongly recommended as they put less stress on the drain field. Filters can be added to new systems or retrofitted to older systems.

How to Tell if There Is a Problem

Unfortunately it isn’t always easy to tell when there is a problem with a septic system.  Since most of the components are underground, you may not discover a problem until long after the breakdown has occurred. However, there are a few symptoms that may indicate a problem:

•    Patches of abnormally healthy-looking grass or vegetation on the drain field are signs that the drain field is full
•    Soft or spongy ground over the drain field can indicate that the drain field is saturated, or full
•    Pools of dark water on the surface point to the same problem
•    Toilets and drains that start backing up or make gurgling noises can be an indication of a blockage or a full system
•    Strong odours can warn of a saturated drain field; foul smells in the house can indicate that wastewater is backing up into the house, or that the house-to-tank pipe is broken

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