Before you commit to a drainage project, you need to understand what drives the cost. French drain pricing varies significantly based on your specific situation—here's a complete breakdown of what Boise homeowners should expect to pay in 2025.
📷 Photo: French drain installation with materials visible
Average French Drain Costs in Boise
Based on our experience installing hundreds of drains throughout the Treasure Valley:
Yard/Exterior French Drain
$40-$80 per linear foot
Typical 50-foot yard drain: $2,000-$4,000
Interior Basement Drain Tile
$100-$150 per linear foot
Typical 120-foot perimeter: $12,000-$18,000
Crawl Space French Drain
$60-$100 per linear foot
Typical 60-foot system: $3,600-$6,000
Foundation Perimeter (Exterior)
$100-$150 per linear foot
Full foundation: $15,000-$30,000+
What Drives the Cost Up
Several factors can push your project toward the higher end:
1. Depth
A shallow 18-inch yard drain costs much less than a 6-foot foundation drain. More digging = more labor = higher cost.
2. Soil Conditions
Boise has some of the most challenging soil in Idaho:
- Hardpan (Caliche): Common on the Bench—nearly as hard as concrete. Requires heavy equipment or jackhammer.
- Large Rocks: Foothill properties often have boulders that extend excavation time.
- High Water Table: Working in standing water slows everything down.
3. Access
Can we get equipment to the work area?
- Full Access: Mini-excavator fits through gate—standard pricing
- Limited Access: Narrow side yard—may require hand digging (+20-40%)
- No Access: Work in backyard with fence removal/rebuild required (+$$$)
4. Discharge Distance
How far must we pipe the water to reach a safe disposal point? Every additional foot of solid PVC discharge pipe adds cost.
5. Restoration Requirements
- Basic: Backfill and grade only (included)
- Sod Replacement: +$3-5/sq ft
- Concrete Cutting & Patching: +$500-1,500 for driveways
- Landscape Restoration: Variable based on complexity
What Drives the Cost Down
- Easy access for equipment (wide gates, no fences)
- Soft soil with no hardpan or rocks
- Short run (though mobilization costs create a minimum)
- Simple restoration (just backfill, no sod/concrete)
- Combining with other work (equipment already on-site)
The ROI Calculation
Before balking at the cost, consider what you're preventing:
Foundation Repair Costs
Helical piers for settling foundation: $10,000-$30,000
Wall stabilization (carbon fiber/I-beams): $5,000-$15,000
Water Damage Costs
Basement finishing destroyed: $15,000-$50,000
Mold remediation: $3,000-$10,000
Prevention Cost
French drain system: $2,000-$6,000
That's 80-95% less than the repair costs
Beware "Too Good" Pricing
If someone quotes you significantly below these ranges, ask questions:
- Are they using rigid PVC or flexible corrugated pipe? (Corrugated crushes and fails)
- Are they using proper filter fabric? (Cheap fabric clogs)
- Are they verifying slope with a laser? (Eyeballing creates ponding)
- Do they have liability insurance? (Underground work is risky)
- What's their warranty? (Cheap work often comes with no warranty)
Get an Accurate Quote
The only way to know your actual cost is an on-site inspection. We provide free, no-obligation estimates with detailed scope of work.