Proper drainage is essential for protecting your home’s foundation, preventing water intrusion, and maintaining the health of your landscape. While surface drainage—like downspouts and grading—can be easily observed, subsurface drainage systems often go unnoticed until there’s a problem. If signs point to poor water management below the surface, a subsurface drainage inspection is recommended to identify issues before they cause long-term damage.
What Is Subsurface Drainage?
Subsurface drainage refers to systems installed below ground to manage water that seeps into the soil. Common components include:
French drains (gravel-filled trenches with perforated pipes)
Drain tiles around foundation footings
Dry wells or catch basins
Sump pumps for groundwater collection
Under-slab drainage systems in basements or crawl spaces
These systems redirect excess moisture away from foundations and low-lying areas to prevent saturation, erosion, and structural damage.
When a Subsurface Drainage Inspection Is Recommended
Persistent Moisture Around Foundation
Wet soil or pooling water near the foundation even during dry periods can signal saturated subsurface conditions.
Basement or Crawl Space Dampness
Musty odors, condensation, or visible water intrusion below grade are signs water may be collecting and not draining properly.
Efflorescence or Mold
White mineral deposits or mold on basement walls often result from prolonged moisture exposure.
Uneven Settling or Cracks
Foundation cracks or sloping floors can stem from unstable, waterlogged soils.
Lawn or Landscape Sinking
Sunken patches in the yard could indicate clogged or collapsed underground pipes.
History of Drainage Problems
Homes with past water issues may have aging or incomplete drainage systems that need evaluation.
What a Subsurface Drainage Inspection Includes
A qualified drainage professional or foundation specialist may perform:
Visual inspection of surface conditions and grading
Moisture readings in crawl spaces or basement walls
Camera scoping of underground drain pipes
Water flow tests to assess drainage performance
Soil saturation tests in problem areas
Inspection of sump pumps or existing French drains
Why It Matters
Ignoring subsurface drainage issues can lead to:
Foundation Damage: Water can weaken or shift structural supports.
Mold and Mildew Growth: A health hazard, especially in closed spaces.
Pest Intrusion: Wet, dark environments attract insects and rodents.
Reduced Property Value: Evidence of water problems can scare off buyers or fail inspections.
Erosion and Landscape Damage: Water can wash away soil, damage plantings, or cause retaining wall failure.
Recommended Next Steps
If a subsurface drainage issue is suspected:
Schedule a professional inspection to identify the source and extent of the issue.
Review findings and plan for repairs, which may include cleaning or replacing drain lines, improving slope and grading, or installing a new French drain or sump pump.
Monitor moisture levels regularly in affected areas, especially after heavy rain.
Final Thoughts
While surface drainage problems are easier to spot, subsurface issues can be far more damaging over time. A proactive inspection can uncover hidden water risks, prevent costly foundation repairs, and keep your home dry and secure from the ground up. If you're seeing signs of moisture or have a history of drainage problems, don't wait—schedule a subsurface drainage inspection to get ahead of the problem.