French Drain Systems: Best Practices for Boulder County Homes
French Drain Systems: Best Practices for Boulder County Homes
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Not All Drains Are Built the Same
French drains are one of the most effective tools for managing water in Colorado yards — but only when installed correctly. Too many fail because they’re shallow, flat, or filled with the wrong materials. Here’s how we build French drain systems that work for the clay soils and weather extremes common across Boulder County and the Front Range.
1. What Is a French Drain?
1. What Is a French Drain?
A French drain is a trench filled with gravel and a perforated pipe that redirects water from soggy areas or foundations to a safe discharge point.
Best for situations when:
Water pools consistently in one spot
Minimal slope limits surface drainage
Soil is heavy clay and drains poorly
Crawlspaces or basements experience water intrusion
2. Key Installation Best Practices
2. Key Installation Best Practices
Proper Depth and Slope
Proper Depth and Slope
Trenches dug 12–18 inches deep minimum
Pipe installed with at least a 1% slope (1 inch drop per 10 feet)
Trenches extend beyond wet zones for full drainage relief
Correct Pipe Type
Correct Pipe Type
Perforated SDR or corrugated pipe wrapped in filter fabric
Solid pipe only used beyond the water collection zone
Gravel Backfill (Never Dirt)
Gravel Backfill (Never Dirt)
Filled with ¾-inch crushed rock or river rock
Geotextile fabric prevents soil from clogging gravel
Dirt is never used to cover the trench; finish with rock, mulch, or sod after sealing
Outlet or Drywell
Outlet or Drywell
Drains must discharge to a downhill daylight, pop-up emitter, or drywell
Without a proper outlet, the system will back up and fail
3. Mistakes We Avoid (That Others Often Make)
3. Mistakes We Avoid (That Others Often Make)
No slope = water won’t flow
Too shallow = prone to freezing or clogging
Wrong pipe = risk of collapse under soil pressure
No geotextile fabric = gravel clogs with clay
Poor outlet = water pools instead of draining
We frequently repair failed DIY or builder-installed French drains that suffer from these issues.
4. When Not to Use a French Drain
4. When Not to Use a French Drain
French drains are effective but not a universal solution. Avoid them if:
The yard requires full regrading instead
Water comes from runoff above (better solved with swales or retaining walls)
There’s no legal or practical place to discharge water
We’ll recommend the best drainage solution tailored to your site conditions.
Related Services:
Related Services:
Need a Drain That Actually Works? We Build Them Right the First Time
Need a Drain That Actually Works? We Build Them Right the First Time
We’ll assess your site and install a long-term solution that moves water the way it should.
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