Excavation
French Drain Cost in Oregon: 2026 Price Guide
Cojo
March 6, 2026
7 min read
Oregon's rainy climate makes drainage one of the most common property concerns for homeowners and commercial property owners alike. French drains are one of the most effective and widely used solutions for managing surface water, protecting foundations, and preventing soggy yards.
A French drain is a gravel-filled trench containing a perforated pipe that collects and redirects groundwater and surface water away from problem areas. The concept is simple, but proper installation is critical, especially in Oregon's clay-heavy soils.
Industry sources have historically reported the following baseline ranges for French drain installation in Oregon:
Industry Baseline Range
| System Type | Cost Per Linear Foot | Typical Project Cost |
|---|---|---|
| Exterior yard drain (basic) | $15 - $70 | $1,000 - $7,000+ |
| Exterior foundation drain | $25 - $120 | $2,000 - $15,000+ |
| Interior basement drain | $30 - $150 | $3,000 - $20,000+ |
| Curtain drain (hillside) | $20 - $90 | $2,000 - $12,000+ |
| Commercial / parking lot drain | $25 - $125 | $3,000 - $35,000+ |
These figures reflect published industry averages. Current market pricing varies significantly and actual quotes may fall well outside these ranges based on soil type, depth requirements, discharge options, and site accessibility.
The industry baseline ranges above represent ideal conditions — easy access, sandy soil, shallow depth, and straightforward discharge. In practice, actual project costs frequently exceed published averages by 2 to 3 times when complications arise. Oregon's clay soils, rocky terrain, deep foundation drains, sump pump requirements, and storm sewer connection permits can all push costs well above baseline figures. The only reliable way to know your actual cost is through an on-site drainage assessment.
French drain projects frequently encounter hidden conditions:
The most common type, an exterior yard drain collects water from low-lying areas, soggy spots, or areas where surface water pools. It redirects water to a lower elevation, dry well, or approved discharge point.
When you need one:
Typical specifications:
A foundation drain sits at the base of your home's footings, collecting water before it can enter your crawlspace or basement. This is the most important drainage system for your home's structural integrity.
When you need one:
Typical specifications:
Installed inside your basement along the perimeter walls, an interior French drain collects water that seeps through or under the foundation and channels it to a sump pit for pumping out.
When you need one:
A curtain drain intercepts subsurface water flowing downhill before it reaches your property or structure. Common in Oregon's hilly terrain.
When you need one:
Oregon's predominant soil types directly affect French drain installation costs:
Clay soils (Willamette Valley, Portland metro): Clay is the most common soil type in western Oregon and the main reason French drains are so widely needed here. Installing a French drain in clay requires wider trenches, more drainage gravel, and filter fabric on all sides. These requirements add 20-30% to installation cost compared to sandy or loamy soils.
Rocky soils (Central Oregon, Cascades foothills): Trenching through rock is slower and harder on equipment. Expect significantly higher trenching costs in rocky terrain. However, rocky soils drain naturally better, so French drains may not need to be as extensive.
Sandy soils (parts of the coast, river valleys): Easiest and cheapest to work with. Sandy soils may not need French drains as often due to natural permeability, but when installed, costs are at the lower end of ranges.
Oregon's western side receives 35-60+ inches of rain annually, with some coastal areas exceeding 80 inches. This volume of water demands properly sized drainage systems — larger pipe diameter, multiple drain lines, and discharge points that handle peak flows.
Where your French drain discharges affects both cost and permitting:
French drains are the preferred solution when water problems are subsurface (groundwater, water table, water migrating through soil). For purely surface water issues, simpler solutions like regrading or surface swales may be more cost-effective. Channel drains work well for driveways and hardscapes. Catch basins collect surface water at low points. The right solution depends on where the water is coming from.
A simple yard drainage French drain (shallow, short run, no connection to sewer) is a manageable DIY project for capable homeowners. You will need trenching tools or a rented mini-excavator, perforated pipe, filter fabric, drainage gravel, and a level to establish proper slope. DIY materials represent a fraction of professional installation cost, but mistakes in slope, depth, or material selection can result in a drain that does not work.
Professional installation is recommended for foundation drains, interior basement drains, any drain connecting to a storm sewer, sites with challenging soil or access, and large or complex drainage systems.
French drains are low-maintenance but not no-maintenance:
A well-maintained French drain should last 30-40 years before needing replacement.
Water problems only get worse with time. What starts as a soggy spot in your yard can progress to foundation damage, mold growth, and structural issues that cost thousands to repair. Addressing drainage proactively is always more cost-effective than reacting to damage.
Cojo provides free drainage assessments for Oregon properties. We will diagnose the source of your water problem and recommend the most effective, cost-appropriate solution.
Schedule your free drainage assessment or learn more about our services. See examples of our drainage and excavation work on our project portfolio.
How much does a French drain cost in Oregon? Industry sources have historically reported French drain installation at $15 to $120+ per linear foot for exterior systems and $30 to $150+ per linear foot for interior basement systems. Actual costs vary significantly based on soil type, depth, discharge requirements, and site accessibility. Current market pricing can fall well outside published ranges, so an on-site drainage assessment is the best way to budget accurately.
How long does a French drain last? A properly installed French drain with quality materials lasts 30-40 years. Using perforated pipe wrapped in filter fabric and clean drainage gravel minimizes clogging, the most common cause of French drain failure.
Can I install a French drain myself? Simple exterior yard drains are a feasible DIY project if you are comfortable with trenching. However, foundation drains, interior basement drains, and systems connecting to storm sewers should be professionally installed to ensure proper slope, depth, and code compliance.
Do French drains work in Oregon's clay soil? Yes, but clay soil requires extra design considerations. The drain trench must be wider, with more drainage gravel, and the pipe must be fully wrapped in filter fabric to prevent clay particles from clogging the system. A properly designed French drain is especially effective in clay because it intercepts water that clay soil cannot absorb.
Do I need a permit for a French drain in Oregon? Permits are generally not required for simple yard drainage French drains. However, if the drain connects to a public storm sewer, changes grading significantly, or is part of a foundation waterproofing system, a permit may be required. Check with your local building department.
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