A French drain in Ottawa costs roughly $35 to $90 per linear foot for a simple exterior yard drain, $100 to $180 per linear foot for an interior perimeter drain (interior weeping tile) inside a basement, and $180 to $350 per linear foot for full exterior foundation excavation and weeping tile replacement. In practical terms, a 60-foot yard drain to move surface water away from a low spot commonly runs $2,500 to $5,000, an interior perimeter system around a typical basement runs $9,000 to $18,000, and a full exterior dig on one or two foundation walls runs $12,000 to $30,000. Ottawa's heavy cla...
The term "French drain" covers three very different jobs, and mixing them up is the fastest route to overpaying. A surface or yard French drain is a shallow gravel-filled trench with perforated pipe that intercepts surface water and directs it away from the house or to a dry well; in Ottawa this runs $35–$90 per linear foot depending on trench depth, whether sod has to be restored, and how far the discharge point is. An interior perimeter drain is installed by jackhammering a channel around the inside edge of the basement slab, laying weeping tile in gravel, tying it to a sump pit, and re-pouring concrete — that's $100–$180 per linear foot in 2026, plus $1,800–$4,000 for a sump pit and pump with a battery backup. An exterior foundation drain replacement means excavating down to the footing, cleaning the wall, applying membrane and dimple board, laying new weeping tile in clear stone, and backfilling: $180–$350 per linear foot, or $12,000–$30,000 for one or two walls of a typical Ottawa home.
Standing water in the yard or a soggy lawn calls for a yard drain. Water seeping through the basement floor-wall joint usually means failed weeping tile, which is solved by either an interior or exterior system. Water coming through a visible foundation crack is often a $600–$1,500 injection repair, not a drainage job at all.
Interior perimeter drains are the more common recommendation in Ottawa because they cost less, are unaffected by weather, and can be installed in February when the ground is frozen solid. They don't touch your landscaping, deck, driveway, or the neighbour's property line — a real advantage on the tight lots common in Westboro, Alta Vista, and Old Ottawa East. The trade-off is that an interior system manages water after it has already reached the foundation, so the wall itself still gets wet and any finished basement along that perimeter has to be demolished back a couple of feet. Exterior excavation is the more complete fix: it keeps water off the wall entirely, allows proper waterproofing membrane, and lets the contractor repair cracks from the outside. But it costs roughly double, requires heavy equipment access, destroys landscaping and sometimes walkways or decks, and can only be done in the non-frozen months. Many Ottawa contractors will recommend exterior work on the one problem wall and skip the rest of the perimeter as a cost-controlled compromise.
Several local factors reliably add cost. Ottawa's Leda clay is dense and slow-draining, and excavating it is harder and slower than sandy soil; some west-end and rural lots also hit bedrock within a few feet, which can add $1,500–$5,000 in rock breaking. Depth matters — a footing 7 feet down costs far more to reach than one at 5 feet. Access is a major driver: if an excavator can't get to the back of the house, the work becomes semi-manual and labour costs can double. Old homes with rubble or fieldstone foundations in Sandy Hill and Lowertown require careful, slower excavation to avoid destabilizing the wall. Discharge is another line item; you need somewhere legal to send the water, and connecting to a storm sewer or installing a dry well adds $1,200–$4,000. Restoration is frequently excluded from base quotes — sod, interlock, decks, and gardens are yours to replace unless the contract says otherwise, which can add thousands.
The City of Ottawa prohibits directing weeping tile and sump discharge into the sanitary sewer system, and the City has run programs encouraging disconnection. Discharge must go to grade, a storm connection, or an approved soakaway — confirm your contractor's plan complies.
Before committing $10,000 or more, rule out the low-cost causes, because a surprising share of Ottawa wet-basement calls are solved for a few hundred dollars. Start with downspouts: they should discharge at least 6 feet from the foundation, and a disconnected or short downspout dumping thousands of litres beside the wall during a spring melt is the single most common culprit. Extensions cost $30–$100 each. Next, check grading — the soil should slope away from the house at roughly 1 inch per foot for the first 6 feet, and re-grading with topsoil typically runs $500–$2,500. Clean and repair eavestroughs ($200–$500). Look for window well drainage problems, which are cheap to fix with a gravel bed and a cover at $200–$600 per well. If a foundation crack is visibly weeping, polyurethane injection from the interior runs $600–$1,500 per crack and carries a transferable warranty from most Ottawa specialists. Only after these are addressed does a full drainage system make sense.
Interior perimeter drain installation that involves removing and re-pouring part of a structural slab, or any work affecting the foundation, generally requires a City of Ottawa building permit — confirm before work starts, because unpermitted foundation work becomes a problem at resale. Utility locates through Ontario One Call are mandatory and free before any exterior digging, and take several business days. On warranties, reputable Ottawa waterproofing companies offer 15-year to lifetime transferable warranties on interior systems; read what is actually covered, since many exclude water entering through cracks above the drain line or through window wells. Get three written quotes and make sure each describes the same scope: linear footage, drain depth, pipe and stone spec, membrane type, sump pit and pump model, backup pump, discharge location, and restoration. Verify liability insurance and WSIB coverage, and ask for addresses of jobs completed two or more spring seasons ago — a drainage system's real test is the April melt.
In 2026, an exterior yard French drain runs about $35–$90 per linear foot, an interior basement perimeter drain runs $100–$180 per linear foot, and full exterior foundation excavation with new weeping tile runs $180–$350 per linear foot. Typical totals are $2,500–$5,000 for a yard drain, $9,000–$18,000 for an interior system, and $12,000–$30,000 for exterior work.
Interior systems cost roughly half as much, can be installed year-round including winter, and don't disturb landscaping — which suits tight urban lots. Exterior excavation is the more complete fix because it keeps water off the foundation wall and allows proper membrane waterproofing, but it costs about double and can only be done in non-frozen months.
Full exterior weeping tile replacement with excavation, wall cleaning, membrane, dimple board, and clear stone typically costs $180–$350 per linear foot, so $12,000–$30,000 for one or two walls of an average home. Rock, deep footings, and poor equipment access push it toward the top of that range.
Interior perimeter drains that involve cutting and re-pouring the basement slab, and any work affecting the foundation, generally require a City of Ottawa building permit. Simple shallow yard drains usually don't, but a free Ontario One Call utility locate is mandatory before any digging.
A properly installed system with clear stone and filter fabric typically lasts 25–40 years. Failures usually come from silt clogging the pipe when filter fabric was skipped, or from crushed pipe. Sump pumps are the weak link and generally need replacing every 7–10 years, which is why a battery backup pump is worth the $600–$1,200.
Check downspouts discharge at least 6 feet from the foundation ($30–$100 per extension), fix negative grading so soil slopes away from the house ($500–$2,500), clean the eavestroughs ($200–$500), and address window well drainage ($200–$600 per well). A weeping foundation crack can often be injected for $600–$1,500 instead of a full drainage system.