What is a French drain?
A French drain typically uses a perforated pipe surrounded by drainage material below ground. Water enters the collection arrangement and is conveyed toward an outlet. The term does not establish the dimensions or suitability of a particular installation.
Sources: Fairfax County / NVSWCD [1]
Does a French drain replace surface drains?
Not necessarily. A system can combine a buried collection line with surface inlets. Northern Virginia’s conservation district describes both runoff and groundwater applications, so “French drain” should not be read as “groundwater only.” Ask what water the proposed component is intended to collect.
Sources: Fairfax County / NVSWCD [1]
What should the proposal explain?
Request a description of the problem addressed, collection area, route and intended discharge. The provider should explain how the proposal fits the property and what conditions remain outside its scope.
A buried line and an outlet are different parts of the system. Do not assume that a street, ditch, neighboring lot or public pipe is an available discharge point. Permissions and site suitability need checking.
Why two French-drain quotes may differ
Use the name as a starting point for comparison, not as a complete specification. Ask each provider to identify included collection points, routing, access, restoration and any separate surface or roof-runoff work.
- What observations support this approach instead of another one?
- What existing components, if any, will remain?
- How will the system be accessed, maintained and supported?
- What changes require a written price or scope approval?
Keep design decisions with the qualified provider
This page does not prescribe trench depth, pipe slope, pump selection or utility clearances. Do not excavate from an online diagram. Use the project checklist to organize your questions, then compare written proposals rather than choosing solely by a per-foot price.
Related: How to compare yard drainage proposals. · Plan your drainage project.
Sources and scope
- Northern Virginia Soil and Water Conservation District: drainage approaches
General terminology and runoff concepts from Virginia; not Texas design or permit requirements. Checked .
Source-check dates show when referenced material was checked. They are not professional approval of a property-specific design. Questions and checklists are homeowner planning aids.