Septic System Installation & Replacement

A septic system is the most expensive thing on a rural property that nobody can see. When it is time for a new one — because the old system failed, because you are building, or because the cottage just became a full-time house — you are buying a design, a permit, an excavation, and an inspection, in that order. We handle the whole chain across the City of Kawartha Lakes.

The honest number first: a full septic system replacement runs $15,000 to $35,000 in Ontario, with most jobs landing between $15,000 and $30,000. Where the site forces a raised mound, it is $25,000 to $45,000. Nobody should hear those numbers for the first time from an invoice, which is why every job here starts with a site visit and ends with a written, itemized quote — and the price only changes if the scope changes, which we tell you before any extra work happens, not after.

Repair, Rehabilitate, or Replace?

Replacement is the last answer, not the first. Before anyone quotes you a system, three cheaper outcomes have to be ruled out:

• It was the tank all along. A cracked baffle, a failed effluent filter, or a tank overdue for a pump-out can produce every symptom of a dying system. These are $200 to $800 problems — see septic tank repair.
• The bed can be rehabilitated. A leaching bed with life left in it can sometimes be brought back for $3,000 to $10,000 instead of replaced. The cases where that works — and the cases where it is money down a hole — are covered under drain field repair.
• Only one component is done. A collapsing tank on a healthy bed, or a finished bed behind a sound tank, can be replaced on its own. Bed replacement alone runs $10,000 to $25,000.

We diagnose before we replace. If a $200–$500 baffle is the fix, that is the quote — not a new system. And when the system genuinely is finished, we say that plainly too, because limping a dead system along has its own price: sewage backups, contaminated ground, and on waterfront lots, effluent heading toward the lake you drink from and swim in.

What the Job Costs

Every price below is the same one we publish everywhere on this site, because a number that changes depending on who answers the phone is not a price.

• Full system replacement: $15,000–$35,000, most jobs $15,000–$30,000
• Raised mound system (where site conditions require it): $25,000–$45,000
• Leaching bed replacement alone: $10,000–$25,000
• Permitting and design for a full Class 4 replacement, before any digging: $3,000–$7,000 — that is the designer's fee ($1,500–$3,500), the City of Kawartha Lakes permit ($500–$800), and the soil work behind the application
• Perc test: $500–$1,500 · Soil profile / deep test pit: $500–$1,000

What moves the number inside those ranges is the site, not the sales pitch: soil depth and quality, access for the excavator, how far the bed sits from the house, and which system type the design lands on. A replacement can also come at a bad moment financially — how to pay for a septic replacement covers the realistic options, including what exists in the way of grants. The replacement cost estimator walks through those same factors and returns an itemized range before you call.

The Process, Start to Finish

1. Site visit. We walk the property, look at the existing system if there is one, and pull whatever records the City has. Paid work starts at step 2, and we say so before it does.
2. Soil work. Test pits and a perc test establish what the soil can actually absorb — this is what decides the system type and most of the price.
3. Design. A licensed sewage system designer stamps a design sized to the house — bedrooms and fixtures, not just current occupants. We coordinate this; you do not need to find your own designer.
4. Permit. The application goes to the City of Kawartha Lakes Building and Septic Division under Part 8 of the Ontario Building Code. Review typically runs 2 to 4 weeks here for straightforward applications. On many properties near water, Kawartha Conservation reviews the application too — we build that into the timeline rather than discovering it late.
5. Installation. The part everyone pictures is the short part: 2 to 5 days of excavation, tank setting, bed construction, and grading for most residential systems.
6. Final inspection and paperwork. The City inspects before backfill and signs off the finished system. You get the documentation — which future-you needs at resale, and which the City keeps on file from then on.

End to end: replacing an existing system typically runs 4 to 8 weeks from first call to finished system. A new-construction system runs 5 to 10 weeks from first site visit to approved installation, because design starts from a blank page. If you are planning a build, bring the septic design in early — it can decide where the house goes, not the other way around. Septic for new construction in Ontario walks through the full sequence.

What We Install

Conventional Class 4 systems — a two-compartment tank feeding a leaching bed — remain the default where the soil allows, and the cheapest to build and maintain. Ontario's five system classes explains where Class 4 sits and why almost every home system is one.

Filter and raised beds take over where soil runs out. Much of the northern half of the municipality sits on shallow soil over bedrock, and waterfront lots add high water tables on top. A raised bed system imports the sand the site does not have. It costs more and stands taller than anyone wants, but it is what makes a compliant system possible on a lot that would otherwise have none.

Tertiary treatment units — Ecoflo, Waterloo Biofilter, and similar Level IV systems — treat effluent to a higher standard before dispersal, which shrinks the bed footprint they need. On tight waterfront lots where a conventional bed cannot meet setbacks, a tertiary unit is often what makes the lot workable at all. They carry a mandatory maintenance contract, and we service them after we install them.

Holding tanks are the fallback where no bed of any kind fits — storage, no treatment, pumped on a schedule. If that is genuinely where your lot lands, holding tank service is its own page, and we will tell you honestly whether you are a holding-tank property before you spend design money finding out.

Cottage Country Is the Hard Case

Most of what makes a septic install difficult is concentrated in exactly the properties this region is made of. Shallow soil over Shield bedrock. Small waterfront lots platted decades before modern setbacks, where the well, the lake, and the property lines box the bed into one possible location — or none. Wells that impose their own distances: a leaching bed must sit 15 metres from a drilled well with a watertight casing at least 6 metres deep, and 30 metres from a dug well. And seasonal cottages converting to full-time use, where a system sized for July weekends meets a family living there year-round.

None of that is a reason to panic; it is a reason to design properly. The systems above exist precisely because this terrain does. What the hard sites punish is guesswork — a bed placed where the excavator could reach rather than where the soil works, a system sized to the current owners instead of the house. That is the difference between a system that quietly works for 25 years and one that greets the next buyer's real-estate inspection with a five-figure surprise.

Start With the Site Visit

Call (705) 702-5526 and describe the property — where it is, what the system is doing (or that there isn't one yet), and what the plan is for the building. We will tell you what the realistic path looks like before anyone commits to anything. If the current system is actively backing up, that is emergency septic service — stabilize first, plan second.

And if you are not sure the system is actually dead, good — start with a septic inspection instead. The cheapest system replacement is the one the assessment proves you do not need.