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O'Fallon, MO

French Drain Installation Cost in O'Fallon

$1,350 – $5,700

Average french drain installation cost in O'Fallon · avg $3,550

  • Updated 2026
  • 12 local pros
  • Based on local project data
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At a glance · O'Fallon
Typical timeline
1–2 days
Permit
Usually required · ~$160
Local soil
expansive clay
Freeze-thaw cycles
47 / yr
Local pros
12 available

French Drain Installation cost in O'Fallon, MO

Perimeter drainage that channels groundwater away from the foundation before it gets in. Below is how it compares with related foundation and drainage work in O'Fallon.

Service in O'FallonLowAverageHigh
Basement Waterproofing$2,100$4,550$6,950
Foundation Repair$2,000$4,850$7,700
Crawl Space Encapsulation$2,750$5,200$7,600
French Drain InstallationThis page$1,350$3,550$5,700
Sump Pump Installation$600$1,350$2,100

Ranges reflect local labor and expansive clay soil conditions. Your quote depends on square footage, access, and severity.

What affects the cost in O'Fallon

Annual rainfall
41"
Freeze-thaw cycles / yr
47
Frost depth
27"

O'Fallon's expansive clay soil swells when it rains and shrinks in dry spells, and that constant movement is the area's leading cause of foundation cracks and wet basements.

Permits in O'Fallon

Structural foundation work and exterior excavation require a permit; interior waterproofing and minor crack sealing usually do not.

Issuing authority: City of O'Fallon Permits & Inspections Office · typical fee ~$160

Get matched with french drain installation pros in O'Fallon

12 established french drain installation companies serve the O'Fallon area. Tell us about your project and compare free quotes, no obligation.

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French Drain Installation in O'Fallon: FAQ

How much does french drain installation cost in O'Fallon?+

In O'Fallon, french drain installation typically runs $1,350–$5,700, averaging about $3,550. The expansive clay soil and 47 freeze-thaw cycles a year are the biggest local price drivers.

Do I need a permit for french drain installation in O'Fallon?+

Structural foundation work and exterior excavation require a permit; interior waterproofing and minor crack sealing usually do not. Permits are handled by City of O'Fallon Permits & Inspections Office, with a typical fee around $160.

Is french drain installation worth it in O'Fallon?+

With 41" of annual rainfall and a 27" frost depth, untreated water intrusion in O'Fallon tends to worsen each freeze-thaw season, so most homeowners find addressing it early is far cheaper than structural repair later.