A complete drainage system project combines trenching labour, typically $8 to $25 per linear foot (see our trenching cost guide), with the drainage stone and pipe material that goes in the trench — clear or clean crushed stone is standard bedding for weeping tile and French drains, since it allows water to move freely to the pipe without silting up over time. Treat every figure on this page as a starting point rather than a quote: the material spec matters as much as the trenching itself, and cutting corners on stone is one of the most common ways a drainage project fails early.
Using the wrong stone — dirty gravel, or stone with too many fines (fine particles that clog void space) — is a common mistake that causes drains to clog and fail within a few years. Clean, washed stone with the correct gradation for your pipe type is not the place to substitute cheaper material to save a small amount upfront, since a failed drain means digging the trench back up to fix what should have worked the first time.
What actually drives the price
System design and length are the starting point, but depth and what the trench crosses affect trenching cost significantly — a straightforward perimeter drain around a foundation is more predictable to price than a system with multiple runs, catch basins, or connections to an existing storm system.
Stone specification and volume matter more than most people expect. The right gradation of clear stone for your pipe diameter and soil conditions is a real engineering decision, not a generic "gravel" purchase — confirm your contractor is specifying stone correctly for the drainage design rather than using whatever is on hand.
Where the water ultimately discharges to affects both design and cost. A system that ties into an existing storm sewer connection is usually simpler than one that needs a new dry well, a soakaway pit, or a pumped discharge because gravity flow to a suitable outlet isn't available on the property. Confirm discharge point early, since it can change the whole system design.
Soil conditions affect both the trenching and how the system performs long-term. Heavy clay soil holds water and often needs a more robust drainage design than sandy, naturally well-draining soil, where a simpler system may be adequate.
Why this is worth doing right the first time
A drainage system that's undersized, poorly specified on stone, or discharges to the wrong place doesn't fail gracefully — it fails by not solving the water problem it was installed to fix, which means the original issue (a wet basement, standing water, foundation moisture) persists or returns, and the fix means reopening a trench that's already been backfilled and landscaped over. Getting the design and material spec right at the start is far cheaper than a redo.
A short checklist before you book
Confirm the drainage design addresses your actual water problem, not just a generic perimeter drain. Confirm stone gradation is specified correctly for your pipe type and soil conditions. Confirm where the system discharges to and that it's a legitimate, functioning outlet. Ask whether the quote includes both trenching and stone material, or trenching only. Confirm depth accounts for your regional frost line if the drain needs to function through winter.
Costs vary by site conditions. Use the ranges here to sanity-check what you're quoted, then get a direct price for your own property.
Submit Your Project — Free, Direct Access to Operators on Pro Operator Network. Need drainage stone? See Aggregate Base for a Concrete Slab on Natural Stone Source Ontario for related material specs, or contact us directly for drainage-specific stone.