French Drain Cost Calculator

French drain costs $20–$60 per linear foot installed. Shallow drain (12–18" deep) costs $20–$35/ft, deep drain (18–24" deep) $35–$60/ft, interior basement drain $50–$100/ft. Average 50 ft project costs $1,000–$3,000. Add $500–$1,200 for sump pump and $150–$400 for downspout connections. Includes trench excavation, perforated pipe, gravel, landscape fabric, and backfill.

French drain is gravel-filled trench with perforated pipe that redirects water away from foundations, basements, or wet areas. Water seeps through gravel into pipe, flows by gravity to outlet (daylight, dry well, storm drain). Components: 12–24" deep trench, landscape fabric liner (prevents clogging), 3–6" gravel base, 4" perforated pipe (holes down), 6–12" gravel cover, topsoil/sod. Slope: 1% minimum (1" drop per 8 ft).

Yes, but physically demanding. DIY saves 50–70% on labor. Rent mini excavator ($250/day) or dig by hand (hard work). Buy: 4" perforated pipe ($1–$2/ft), landscape fabric ($0.30/sq ft), gravel ($30–$50/ton), fittings ($20–$50). Steps: mark utilities (call 811), dig trench with 1% slope, line with fabric, add gravel base, lay pipe (holes down), cover with gravel, wrap fabric, backfill. Takes 2–3 days for 50 ft. Hire pro for complex sites or basement drains.

Shallow French drain: 12–18" deep for surface water, yard drainage, downspout runoff. Most common residential application. Deep French drain: 18–24" deep for groundwater, foundation protection, wet basements. Must be below frost line in cold climates (varies by state: 12" in south, 48" in Minnesota). Interior basement drain: 12" below basement floor level. Depth also depends on outlet elevation — drain must slope downhill to outlet.

Outlet options: Daylight (best): drain to surface at lower elevation, 10+ ft from property line. Dry well: underground gravel pit (3–5 ft deep, 3–4 ft diameter) for water absorption, illegal in some areas. Storm drain: connect to municipal storm system (requires permit). Sump pump: pump water uphill if no downslope available ($500–$1,200). Never outlet to septic system, neighbor's property, or within 10 ft of foundation. Check local codes.

French drain lasts 15–40 years depending on installation quality and maintenance. Properly installed with landscape fabric: 30–40 years. Without fabric (clogs faster): 15–25 years. Common failures: silt/sediment clogs perforations (clean every 5–10 years), tree roots invade pipe (avoid trees within 10 ft), pipe crushes (use solid pipe under driveways), improper slope (standing water). Regular maintenance: flush with hose annually, inspect after heavy rains.

Add sump pump ($500–$1,200) if: no downslope outlet available (uphill discharge required), interior basement drain (pump water outside), water table high (drain fills quickly), wet basement (backup pumping needed). Sump pump not needed if: drain outlets to daylight or storm drain, adequate slope for gravity flow. Battery backup sump pump ($800–$1,500) recommended for basements to prevent flooding during power outages.

French drain: underground, handles groundwater + surface water, invisible after installation, lasts 30+ years, costs $20–$60/ft, harder to clean. Best for: wet basements, foundation drainage, large areas, permanent solution. Surface drain (channel drain): above ground grate, handles surface water only, visible, lasts 20+ years, costs $10–$30/ft, easy to clean. Best for: driveways, patios, pool decks, heavy rain runoff. Use both together for comprehensive drainage.