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Septic Types2026Tiny, Tay, Midland, Wasaga, Collingwood
Septic System Types Compared: Conventional to Tertiary
A conventional trench bed is the cheapest at about $25,000-$40,000 in 2026, a filter bed runs $30,000-$45,000, a raised bed $30,000-$50,000, and a tertiary unit $35,000-$65,000+ plus a yearly service contract. Your soil, water table and lot size pick the type more than you do, and this page shows why.
Updated October 2026 · Georgian Bay Siteworks, the site work division of ICFHome.ca
Insured to $2,000,000Site work division of ICFHome.caBuilding since 1979250+ projects in Simcoe County
The Short Version First
Nobody walks into a septic job and orders a filter bed because they like the name. The designer digs test holes, finds the soil type, the T-time (how fast water soaks in) and the depth to water or rock, then counts your bedrooms. Those numbers decide which system fits on your lot. Your job is to understand the trade-offs so the price does not surprise you.
| Type | When it is needed | Footprint | Rough price (2026) | Maintenance | Pros / cons |
|---|---|---|---|---|---|
| Conventional trench bed | Decent native soil, 900 mm+ to water or rock under the stone | Largest – long runs of pipe in trenches | $25,000-$40,000 | Pump tank every 3-5 years, clean effluent filter yearly | Cheapest, no power if gravity fed / needs the most room |
| Filter bed | Smaller lots, or where the trench layout will not fit | Compact sand bed plus a contact area | $30,000-$45,000 | Same as conventional | Fits tight lots / imported filter sand costs money, handles heavy flow less well |
| Raised (or partially raised) bed | High water table, shallow rock or tight clay | Bed footprint plus side slopes and sand mantle | $30,000-$50,000 | Same, plus keep the slopes stable and grassed | Works where nothing in-ground will / sits up like a mound, more fill trucked in |
| Tertiary / advanced (Waterloo Biofilter, Ecoflo and similar) | Small lots, waterfront, poor soil, or to shrink the bed | Treatment unit plus a reduced bed | $35,000-$65,000+ | Mandatory service contract, often yearly; media replacement over time | Cleanest effluent, smallest bed / ongoing cost, needs power, has alarms |
| Holding tank (Class 5) | Last resort where nothing else fits, or temporary | Tank only | Not priced here – depends on tank and dig | Pumped out every time it fills | Small footprint / pump-out bills never stop, approval is restricted |
Price ranges for the first four come from our septic cost guide and SepticReplacement.ca. What moves the number: how much imported sand comes in, access for trucks, rock, tree clearing, and how far the bed is from the house.
How Big Is Each Bed? A Worked Example
Here is a rough sizing using the Building Code formulas as summarized on the Huntsville septic calculation sheet. Assumptions: a 4-bedroom house under 200 m2, design flow 2,000 L/day, sandy soil with a T-time of 10. This is for understanding only, not a design.
- Conventional trenches: pipe length = flow x T / 200 = 2,000 x 10 / 200 = 100 m of distribution pipe (minimum is 40 m).
- Filter bed: loading area = flow / 75 = about 27 m2 of filter sand on top, plus a contact area underneath sized from the T-time.
- Septic tank: twice the daily flow, so 4,000 L, and never under 3,600 L.
That is why filter beds win on small Tiny and Wasaga lots. One hundred metres of trench takes a lot of yard. Change the soil to slow clay and the trench length climbs fast.
Builder truth: the free septic check will give you a better first answer on tank and bed size than any rule of thumb on a forum.
Filter Beds and Raised Beds
A filter bed is one sand bed with the pipes on top instead of a field of trenches. The Oro-Medonte Septic Smart guide describes it plainly: good for small lots where separation distances are tight, but it cannot process heavy flows as well as a conventional bed. Our filter bed page goes deeper.
A raised bed is either type built up above grade because the native ground does not give enough separation to water, rock or tight soil. The Code wants about 900 mm of unsaturated soil under the stone. If the water table is at 600 mm in April, the bed goes up. Raised beds cost more because the sand comes in by the truckload, and the setbacks grow too (about 2 m extra for each 1 m of rise).
Tertiary Units: Is a Waterloo Biofilter Expensive to Maintain?
It costs more to own than a plain bed, but it is not a money pit if you keep the contract current. These units treat the effluent much harder before it hits the ground, which is what lets a designer use a smaller bed. The catch is a service contract you cannot skip. Springwater, for example, requires a renewable maintenance contract for Level II to IV treatment units, and Innisfil wants the contract with the permit.
Real numbers are thin online. One owner review on HomeStars cites roughly $300 a year for the mandatory Waterloo Biofilter contract, plus about $200 in emergency calls one year. The Ecoflo Ontario owner’s manual includes the first year of maintenance with purchase, then a maintenance agreement, and the filter media gets replaced when the service tech says it is done.
Rough range (2026): budget $300-$600 a year for service, plus the regular tank pump-out, plus a media replacement down the road. Ask for the contract price and the media replacement price in writing before you choose the unit. Those two numbers vary by brand and service area.
Holding Tanks: Only When Nothing Else Fits
A holding tank stores everything and gets pumped when it fills. No bed at all. Ontario’s Guideline F-9 says they should not be approved for new homes except in narrow cases, like an existing pollution problem on a lot too small for a bed, or an interim service until sewers arrive. Tiny has more than 500 holding tanks, and Midland has stopped accepting hauled septage, so disposal is not getting easier around here.
The real cost is pumping. A Cottage Life Q&A quotes around $300 per pump-out, weekly for a family of four all summer (a B.C. figure). Do that math over a season before you call a holding tank cheap.
Not Sure Which Type Your Lot Needs?
Start with the free septic check, then get a design from SepticReplacement.ca. We handle the clearing, digging and install work once it is permitted.
Related guides
Frequently Asked Questions
What is the cheapest septic system in Ontario?
A conventional trench bed in good native soil, at roughly $25,000-$40,000 in 2026. It only works where you have the room and enough depth to water and rock.
Is a Waterloo Biofilter expensive to maintain?
It costs more than a plain bed because a service contract is mandatory. One owner review cites about $300 a year; budget $300-$600 a year plus pump-outs and eventual media replacement, and get the prices in writing first.
What size septic tank do I need?
Under the Code a house tank holds at least twice the daily design flow and never less than 3,600 L, so a 4-bedroom house at 2,000 L/day needs about 4,000 L. Run the free septic check for your own numbers.
Why would I need a raised bed?
Because the ground does not give about 900 mm of separation between the stone and the water table, rock or tight soil. The bed is built up with imported sand to make that separation.
Can I choose a holding tank instead of a bed?
Usually not. Ontario guidance restricts holding tanks for new homes to narrow cases, and the ongoing pump-out cost is high.
Does a tertiary system make the bed smaller?
Yes, the better-treated effluent allows a reduced bed, which is why they are common on small waterfront lots. The designer confirms the size for your site.
