French drain pricing runs $20-$80 per linear foot installed in 2026, with depth and access driving the range. Shallow surface drains (12 inches deep): $20-$35/lf. Standard foundation perimeter drains (24-36 inches deep): $35-$65/lf. Deep basement drains or drains requiring hand-digging in tight areas: $55-$80/lf. Typical 60-100 foot installations land $3,000-$6,500.
Anatomy of a drain that works
Proper French drain construction: trench 24-36 inches deep (below frost line), 6 inches wider than pipe, lined with woven filter fabric, 4-inch perforated PVC pipe (perforations down) laid on 2 inches of clean 3/4-inch stone, backfilled with more clean stone to within 4 inches of surface, fabric wrapped over stone to prevent fines migration, topped with soil or mulch. Daylighted exit at lowest point drains to somewhere water can go safely — never onto neighbor's property.
Where to install — diagnosing the problem
Water in basement, against foundation: foundation perimeter drain, 24-48 inches deep, tied to sump pump or daylight exit. Saturated yard or lawn: surface drain or shallow yard drain 12-18 inches deep. Hillside water causing erosion: interceptor drain uphill of the problem, 24-36 inches deep. Water under slab (interior): interior drain along slab edge with sump — requires breaking slab and is most expensive install type.
DIY French drain reality
French drains are among the most DIY-friendly drainage projects. Hand-dig or rental mini-excavator ($350-$500/day) handles most residential trenches. Materials (pipe, fabric, gravel) run $8-$18 per linear foot. DIY labor 2-4 days per 50 feet of drain. Key quality factors: consistent slope (1/8 to 1/4 inch per foot toward outlet), proper fabric wrapping, and daylighted exit. Skip any of these and the drain fails within 2-5 years.