Septic Beds

How to troubleshoot a backed-up septic system?

First of all, take a deep breath. Many septic issues that seem catastrophic at first can turn out to be a simple septic system repair. You may even be able to perform some of these steps yourself! These instructions aim to guide you in the right direction and help you get your drains flowing again in short order.

Start with the Septic Tank

Step 1 – Locate the Septic Tank

See “How to Locate My Septic Tank” for detailed instructions.

In some cases, the location of the septic tank is obvious because of a tank lid collapse. If this happens, the tank will likely require repair or replacement. Unless the collapse was caused by external mechanical forces (e.g., a vehicle driving over it), repairs are often not cost-effective. This is because septic gases are corrosive to older pre-cast concrete tanks, and a collapsed lid usually indicates poor overall tank condition above the waterline.

Over time corrosive septic gasses can corrode some precast concrete septic tanks above the waterline, ultimately causing septic tank failure – Flamborough

Many older tanks are also undersized by today’s standards and may lack an effluent filter or risers to grade. In most cases, replacement is more cost-effective than repairing or upgrading an existing septic tank. Site conditions and accessibility may influence this decision.

Important: Never enter a septic or wastewater tank to repair it. Septic tanks may contain poisonous gases and are considered confined spaces under Ontario law.

Step 2 – Expose and Open the Septic Tank

Once you’ve identified the septic tank lids, expose and open them. Typically, there should be two lids. Use appropriate personal protective equipment (PPE) and exercise caution, as raw sewage is inside the tank. If your system has more than two lids, open only the first two for now (those closest to the house). Step back and allow the odor to dissipate.

Step 3 – Observe the Liquid Level in the Septic Tank

When opening the tank, many people are alarmed to see it is full. Don’t panic—a septic tank is designed to operate in a nearly full condition. Here’s how to determine if the liquid level is normal:

  • Take Photos: Document what you see. These can be valuable for future reference.
  • Assess:
    • If liquid overflows or seeps out before opening the lid fully, pump the septic tank to gather more useful information.
    • If the tank is mostly full but not overflowing, make further observations.
  • Normal Conditions: The liquid may appear relatively clear or covered by a thick scum layer. Both are normal.

    Look for the inlet and outlet baffles or an effluent filter. If the tank is old or poorly maintained, these components may be broken or submerged. If the liquid level is above the inlet/outlet baffles or effluent filter, the tank is too full and should be pumped to proceed.

    Key Point: In a properly operating tank, the liquid level should rest at the bottom pipe that drains the effluent filter or outlet baffle.

    Risers were added to this septic tank to make regular servicing of the effluent filter possible – Burlington

    Step 4 – Observe the baffles and septic lateral

  • Check the Inlet Baffle for Blockages: Look for trapped items and gently clear them with a stick or by suction using the vacuum hose from the septic vac truck.
    • Remember: After clearing the inlet with vacuum, run water down each drain to refill the building’s P-traps, as suction may pull the water out.
  • Inspect the Lateral Pipe: Investigate the pipe between the house and tank. Settling, freezing (in winter), or mechanical damage can cause blockages. Use a mechanical snake or high-pressure water jet to clear the pipe if needed. Sewer cameras can help identify issues.
  • Possible Outcome: If the tank is pumped and the lateral is clear, but you still have drain problems, the issue lies within the house plumbing—not the septic system.

    Effluent Filter Maintenance

    Effluent filters, found on the outlet side of many tanks, prevent solids from reaching the leaching bed. These filters require cleaning 1-2 times per year. If the filter is underwater, it is likely blocked and should not be removed until the tank is pumped.

    Important: Removing a submerged filter can cause a sudden surge of untreated wastewater to the leaching bed, carrying grease and solids that may clog it.

    • An effluent filter helps protect the septic bed and should be installed on the outlet side of every new septic tank – Halton

    Step 5 – Pump the Septic Tank and Observe

    Even if the liquid level is proper, pumping the tank is a cost-effective preventative measure and will make the following steps easier. Pumping the tank also allows you to gather additional information:

  • Check Inlet Flow: Observe if water flows easily into the tank as the level drops.
  • Inspect the Effluent Filter: If clogged, clean it and monitor for recurring issues.
  • Watch for Backflow from the Leaching Bed:
    • Short-duration backflow suggests nearby blockages, which are often repairable.
    • Continuous backflow indicates a saturated leaching bed, requiring major repair or replacement.
    • If large volumes of water flow back into the septic tank after the tank is pumped, the septic bed is likely saturated, this outlet baffle is missing – Ontario

    Reminder: Pumping the tank provides temporary relief but does not resolve systemic issues, such as a failing leaching bed.

    Conclusion

    If troubleshooting reveals a plumbing problem within the house, contact a plumber. If the issue involves the septic system, consider consulting a professional for long-term solutions, such as repairing or replacing the leaching bed. Regular maintenance, including pumping, effluent filter cleaning, and proper waste disposal, is key to preventing future problems.