The septic report lands in your inbox the evening before your condition deadline and it is full of words like baffle, invert, mantle, and Class 4. This guide explains how our septic reports are organized, what the terms mean, which findings should change your decision or your price, and which are the normal upkeep of owning a rural property.
Written by John Hansen, Registered Home Inspector, Past President of the Ontario Association of Home Inspectors, WETT certified, BCIN qualified for septic systems. Inspecting since 2011.
At a glance
- Read the system description first so you know what kind of system you are buying and how old it is.
- Find the summary of failures and separate them from maintenance and monitoring items.
- Check the tank findings: material, baffles, filter, liquid level, and infiltration.
- Check the leaching bed findings: saturation, surfacing, backflow, and load test results.
- Compare the system size and setbacks with the house as it is today.
- Note the limitations section, which tells you what could not be seen.
- Decide what to do: ask for quotes, negotiate, extend the condition, or walk away.
Start with the system description
The first page tells you what you are dealing with. It identifies the class of system under Part 8 of the Ontario Building Code, the tank material and approximate volume, the number of compartments, whether there is an effluent filter, the type of leaching bed, and the age if it could be established from the permit or the owner. Most houses in Southern Ontario have a Class 4 system: a septic tank followed by a leaching bed of some kind. A conventional in-ground bed, a raised bed built in imported sand, a filter bed, and a bed fed by a tertiary treatment unit all behave and age differently, so this paragraph sets the context for everything that follows.
- Septic tank: the buried chamber where solids settle and scum floats. Effluent, the liquid in between, flows out to the bed.
- Baffles or tees: the fittings at the inlet and outlet that keep scum and solids in the tank. A missing outlet baffle is a finding, not a note.
- Effluent filter: a removable screen on the outlet that protects the bed from solids. It needs cleaning when the tank is pumped.
- Distribution box: the small chamber that splits effluent between the runs of a conventional bed.
- Leaching bed, tile bed, or weeping bed: the network of perforated pipe in stone where effluent soaks into the soil. These terms mean the same thing.
- Raised bed or filter bed: a bed built above the natural grade in sand, used where the native soil or the water table will not allow an in-ground bed. The sand layer is the mantle.
- Tertiary treatment unit: an aerobic unit or biofilter that treats effluent before the bed. In Ontario most of these require an ongoing maintenance agreement.
- Pump chamber: the tank and pump that lift effluent to a raised bed, with floats and a high-level alarm.
Failures, repairs, and maintenance are different things
Our reports sort findings into three groups so the serious ones do not get lost. A failure is something that means the system is not treating or disposing of sewage as designed: effluent on the surface, water flowing back from the bed into the tank, a cracked tank taking on groundwater, a collapsed baffle, or a pump that does not run. A repair is a defect that will become a failure if it is left: a tilted distribution box, a corroding steel tank, roots in the outlet, an alarm that does not sound. A maintenance item is the normal upkeep every system needs: pumping on a schedule, cleaning the filter, keeping the bed clear of traffic and deep-rooted plants.
A long list is not the same as a bad system. A thirty-year-old system with eight maintenance notes and no failures is often in better shape than a ten-year-old system with one failure on the leaching bed.
Red flags
Findings that should change the price or the decision
- Effluent surfacing on or beside the bed, sewage odour outdoors, or staining downslope. The bed is not absorbing what it receives.
- Water running back into the tank from the outlet pipe when the tank was pumped. The bed or the distribution system is saturated.
- Liquid level in the tank above the outlet invert before pumping.
- A tank that is cracked, collapsing, or taking on groundwater, or a steel tank with significant corrosion.
- A system that is clearly undersized for the house as it stands today, especially where bedrooms or bathrooms were added without a permit.
- Setbacks to the well that are well short of the code minimums, or a bed that drains toward the well.
- No permit on file for a system that is recent enough to have needed one, or a system that does not match the permit.
- A pump chamber with a dead pump, failed floats, or no working alarm on a raised bed, which means a backup is coming.
Yellow flags
Findings to budget for or to monitor
- No effluent filter on an older tank. Inexpensive to add at the next pump-out, and it extends the life of the bed.
- Lids below grade and no risers. Add them so every future service visit does not start with a shovel.
- Heavy sludge and scum for the household size. The pumping interval needs to be shorter.
- Lush grass over the bed, or a bed that is softer or wetter than the surrounding lawn, without surfacing. Monitor after wet seasons.
- A distribution box that is slightly off level or has some solids in it.
- Trees, shrubs, a shed, or a parking area on or near the bed.
- A tertiary treatment unit with no current maintenance agreement, which is also a compliance issue.
- A system approaching the end of its typical service life with no faults yet. Plan, do not panic.
Read the limitations
Every honest septic report has a section listing what could not be inspected and why: a lid that could not be found, a bed under snow, a tank that was pumped before we arrived, a vacant house with no recent flow. These limitations are not boilerplate. If the tank interior was not seen at operating level or the bed could not be probed because the ground was frozen, the parts of the report that depend on those observations carry less weight, and you may want to make the inspection of those parts a condition or a holdback.
Sizing and the house
The report compares the system with the house it serves. In Ontario the daily design flow, and therefore the size of the tank and bed, is set largely by the number of bedrooms and the fixtures in the house, adjusted for the soil. If the house has grown since the system was built, the report will say so. This is one of the most common findings on older farmhouses and cottages that have been expanded, and it matters even when the system is working, because the authority will size any replacement to the house as it stands now.
What to do next
- Call us if anything is unclear. Going through the report together takes ten minutes and prevents most misunderstandings.
- For a failure or a significant repair, get a written quote from a licensed septic installer before the condition date. Replacement in Ontario needs a permit from the principal authority and the design depends on the soil, so quotes vary widely.
- Decide with your lawyer and agent whether to negotiate a price reduction, ask the seller to complete the work with a permit and final inspection, hold funds back, or extend the condition.
- For yellow flags, make a maintenance plan: pumping interval, filter cleaning, a riser installation, and a note of where the bed is so nobody parks on it.
- Keep the report. It is the baseline for the next owner and useful if a problem appears later.
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FAQs
The report says the system is at the end of its typical life but found no failures. Should I walk away?
Not necessarily. It means you should budget for replacement within the next several years and negotiate with that in mind. Many systems run past their typical life when they have been pumped regularly and the bed has been left alone.
Why does the report not give a replacement price?
Because the price depends on a design that has not been done yet: soil tests, the lot, the setbacks, the size of the house, and whether a raised bed or a treatment unit is needed. We describe what a replacement would involve and recommend getting quotes from licensed installers; a number without a design would mislead you in one direction or the other.
What does backflow from the bed mean?
When the tank is pumped and the liquid level drops below the outlet, a healthy bed stays put. If water flows back into the tank from the outlet pipe, the pipe and bed are holding water they cannot absorb. It is one of the most reliable signs of a saturated or failing bed and it is why we pump during the inspection rather than before.