Ontario · Owner-builder · 2026
The owner-builder septic material list: real quantities, real formulas
The fastest way to blow an owner-builder budget is ordering material twice — or running out of stone with an open excavation and a machine on the clock. Here is the full list with the formulas that produce the right order the first time.
The builder’s rules: price everything from EXCAVATION dimensions — the bed plus 1 ft of over-dig on every side — not the design dimensions. Order pipe with 20% waste, stone and sand with 10%. That is the difference between a textbook estimate and what actually shows up on trucks.
FREE 2026 PDF
Homeowner’s Guide44 pp.
Costs, permits, contractor vetting, and the owner-builder path — updated for the 2026 Building Code.
No spam. Straight talk from a builder.
1 Something’s wrong2 What it costs3 The permit4 Who designs it5 The paperwork6 Approval
The part nobody tells you
Designers charge $800–$2,000 just for the paperwork in these quotes.
Ontario law lets you do that part yourself, on your own property. OntarioSepticDesigner.ca turns your answers into the same 26-page package the township clerk sees every day — calculations, drawings, forms, all of it.
The complete list for a conventional trench bed
✓Septic tank — the size your flow calculation requires (3,600 L minimum, two compartments, effluent filter), plus delivery and crane/setting
✓Distribution pipe — 100 mm perforated, in 10 ft lengths
✓Solid pipe — tank to bed, house to tank, with fittings and glue
✓Clear septic stone — washed, per Table 8.7.3.4
✓Filter fabric — over the stone, before backfill
✓Marker stakes — so future owners (and the pumper) can find the runs
✓Machine time — excavator and operator, plus labour for pipe and stone placement
✓Imported sand — only for raised or fill-based beds; the big variable on difficult lots
The formulas, with a real worked example
Take the 3-bedroom bungalow we use across this site: Q = 1,600 L/day, soil T-time of 18 (from the test holes).
| Item | Formula | This project |
|---|---|---|
| Pipe length (design) | L = Q × T ÷ 200 | 144 m (473 ft) |
| Pipe to order | design ft × 1.20, in 10 ft lengths | 57 lengths |
| Runs | max 30 m each, 1.6 m centres | 5 runs × 28.8 m |
| Excavation footprint | bed + 1 ft over-dig each side | 29.4 m × 7.6 m |
| Stone volume | runs × length × 0.6 m × 0.25 m | 21.6 m³ |
| Stone to order | volume × 1.10 | 23.8 m³ |
Why the over-dig matters to your wallet
You dig one foot wider than the bed on every side to work in. Every supplier quote, every truckload of stone, and every hour of machine time follows the excavation footprint, not the drawing. Price from the design dimensions and you will be roughly 10–15% short on everything.
The $18,950 line that never appears on a quote
A real worked example: 3-bedroom bungalow, conventional bed. Tank supplied and set, pipe, stone, fabric, one day of machine and labour, permit allowance — $13,049 with HST. The same job quoted at $32,000. The gap is design fees, markup, and labour you may not need to buy.
Two minutes on the free checker shows the numbers your own lot generates — daily flow, tank size, risk level — before anyone quotes you.
What this costs, all in
Same worked example, current planning prices: tank supplied and set $4,000; pipe $1,425; stone $1,953; fabric, fittings and stakes $510; excavator, operator and two labourers for the day $2,560; permit and testing allowance $1,100. $11,548 before HST — $13,049 all in. Against a $32,000 quote for the same job, the difference is what you keep for doing the paperwork and managing the build. Planning estimate only — your suppliers, trucking distance and site set the real numbers.
Ordering day tips from the field
Confirm the stone is washed septic stone — dirty stone plugs a bed. Get the tank delivery and the crane on the same booking. Have the fabric on site before the stone truck comes, not after. And stake your runs before the machine arrives so the operator is never waiting on you.
Material questions, answered straight
How much stone do I need for a septic bed?
Runs × run length × 0.6 m width × 0.25 m depth, plus 10% waste. For a typical 3-bedroom conventional bed: about 24 m³ delivered.
How much pipe for a leaching bed?
Q × T ÷ 200 gives metres of pipe; order 20% extra in 10 ft lengths. A 3-bedroom house on T=18 soil needs 144 m designed, 57 lengths ordered.
Can I use any gravel?
No — the Code requires clean, washed stone in the sizes of Table 8.7.3.4. Fines and dirt in cheap gravel are how new beds fail early.
Do I need imported sand?
Only for raised or fill-based beds where native soil or water table forces the bed up — sand and stone formulas here. On a conventional in-ground bed in decent soil: none.
Get the takeoff without the spreadsheet
The builder produces this exact material list from your numbers — pipe lengths, stone with waste, the excavation footprint — as part of the $99.99 package.