History and Purpose

• The French drain is named for its developer and advocate, a New Hampshire farmer named Henry Flagg French. His book published in 1860, "Farm Drainage -- The Principles, Processes, and Effects of Draining Land with Stones, Wood, Plows, and Open Ditches, and Especially with Tiles," described his method for diverting groundwater with potential to cause damage.
  
  

Use of Gravity

• Slope is important in the design of a French drain. If proper slope can be achieved, gravity will carry away excess water without the need for an auxiliary pump. Even relatively complex French drain systems can be devised where pipes run both vertically and horizontally. Lines can be sloped to catch water from a hill above a structure, divert water off to the sides, connect with other lines that run downhill and carry water safely away. In essence, the French drain becomes a moat that protects the house, leaving it on drier land than it would be without the intervention of the drain.
  
  

Appropriate Tools

• The creation of French drain system requires tools appropriate to the task. First is a method for digging a trench. In instances where digging of earth is not impeded, a shovel and pick can suffice. On land where rocks and tree roots are part of the terrain, powered, a mechanized tool such as a trencher, also known as a "ditch witch," can facilitate the digging. If deeply rooted sod is present, a sod cutter may be useful. For building the drain, necessities include the plastic or PVC drainpipe, rock or gravel and a wheelbarrow to haul the fill materials. Other commonly used tools are plastic tarps on which to lay materials, empty barrels or other large receptacles for containing moved earth, duct tape, boards for temporary bracing and common carpenter's tools, including a level.
  
  

DYI vs. Professional

• Often, building a French drain system is done by individuals who engage in do-it-yourself projects. Some instances, however, may require the expertise of a professional. As one example, permits may be required in some areas. Enforcement of environmental regulations and building codes may be an issue. Additionally, if excessive water runoff is instrumental in potential threat to existing structures, encroaching on the property of others or causing health concerns, a professional may need to certify that problems have been mitigated to release the homeowner from liability.
  
  

Other Considerations

• Extremes in weather are often at the root of drainage problems. In some locations, a French drain may alleviate flooding conditions entirely. In others, it may not. In that instance, sump pumps may need to be installed to assist in the excess water removal. Power outages may be a problem in areas where flooding occurs. Having a generator to provide backup power for sump pumps can help a French drain effectively divert excess water flow in the face of potentially damaging flooding even when the usual power source is interrupted.