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Thornton, CO

French Drain Installation Cost in Thornton

$1,550 – $6,300

Average french drain installation cost in Thornton · avg $3,950

  • Updated 2026
  • 12 local pros
  • Based on local project data
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At a glance · Thornton
Typical timeline
1–2 days
Permit
Usually required · ~$170
Local soil
expansive clay and bentonite
Freeze-thaw cycles
94 / yr
Local pros
12 available

French Drain Installation cost in Thornton, CO

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 Thornton.

Service in ThorntonLowAverageHigh
Basement Waterproofing$2,400$5,050$7,650
Foundation Repair$2,300$5,400$8,500
Crawl Space Encapsulation$3,100$5,750$8,400
French Drain InstallationThis page$1,550$3,950$6,300
Sump Pump Installation$700$1,500$2,300

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

What affects the cost in Thornton

Annual rainfall
17"
Freeze-thaw cycles / yr
94
Frost depth
33"

Thornton'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 Thornton

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

Issuing authority: City of Thornton Building & Zoning Department · typical fee ~$170

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

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French Drain Installation in Thornton: FAQ

How much does french drain installation cost in Thornton?+

In Thornton, french drain installation typically runs $1,550–$6,300, averaging about $3,950. The expansive clay and bentonite soil and 94 freeze-thaw cycles a year are the biggest local price drivers.

Do I need a permit for french drain installation in Thornton?+

Structural foundation work and exterior excavation require a permit; interior waterproofing and minor crack sealing usually do not. Permits are handled by City of Thornton Building & Zoning Department, with a typical fee around $170.

Is french drain installation worth it in Thornton?+

With 17" of annual rainfall and a 33" frost depth, untreated water intrusion in Thornton tends to worsen each freeze-thaw season, so most homeowners find addressing it early is far cheaper than structural repair later.