Signs a drainage review may help
- Water along the basement wall-floor joint
- Repeat seepage after rain
- Standing water in a crawl space
- Damp areas in a hillside garage
- Water pooling in a low exterior area
- Runoff moving toward the building
- A sump pump that runs frequently
- White mineral deposits near damp concrete
These signs do not automatically mean a French drain is required. Surface water, plumbing, cracks, grading, and below-ground moisture need different responses.
Interior and exterior French drains
Interior perimeter drainage
Installed near the inside basement edge to collect water from the wall-floor area or below the slab and direct it toward a sump basin or suitable outlet.
Exterior subsurface drainage
Placed near an exterior foundation or wet area to intercept subsurface water before it reaches an at-risk wall, crawl space, or lower area.
What a drainage system may include
Collection trench
Depth and position should correspond to the likely source and grade.
Perforated pipe
Receives water through openings and carries it along the planned route.
Drainage stone
Supports collection and helps water reach the pipe while limiting soil movement.
Outlet or sump basin
The final destination must move collected water away without returning it to the foundation.
French drains versus surface drains
A French drain manages water moving through soil. Area drains, channel drains, and catch basins collect visible surface runoff. Other options may include swales, downspout drainage, solid underground pipes, and grading corrections. A property may need more than one system because surface runoff and subsurface water behave differently.
Pasadena drainage planning
Level lots, hillside properties, raised foundations, changing grades, patios, driveways, and tight side yards can change the route. A layout that works for one street may not fit another. We consider the source, slope, outlet, foundation depth, utilities, and access before recommending a path.
Our drainage-system process
- Discuss when and where water appears.
- Review the affected area, accessible exterior, and existing drainage.
- Identify the likely water source and collection point.
- Plan the route, slope, pipe, basin connection, and outlet.
- Complete the approved excavation and drainage installation.
- Review the finished system and maintenance needs.
French drain installation cost
- Drain length and depth
- Interior or exterior location
- Concrete removal
- Excavation access
- Soil and slope
- Pipe and stone requirements
- Sump basin connection
- Discharge route
- Surface restoration
- Obstacles and utilities
Drainage FAQs
An interior perimeter drain may collect water near the slab edge and direct it to a sump system. It must be placed where it can intercept the actual water path.
No. Some drains can use gravity when a suitable lower outlet exists. A pump may be needed when gravity cannot move the collected water safely.
Roof water is usually handled through a solid drainage route rather than the same perforated pipe used to collect groundwater. The full layout should be planned carefully.