French Drain Cost

How Much Does a French Drain Cost?

Outdoor French Drain: $300-$1,500

Interior French Drain: $2,000-$15,000+

Also called a trench drain, blind drain, rubble drain, drain tile, perimeter drain or land drain, a French drain is a trench covered with gravel or rock which directs surface groundwater away from an area. They typically include a perforated PVC pipe and are installed underground, hidden from view by a layer of sod or dirt. French drains are primarily used outdoors, although they can be installed indoors to dry out a soggy basement.

Typical costs:

Having a landscaper or other professional install outdoor French drains can cost $10-$30 a linear foot but averages about $25/foot depending on depth and width (typically 12"-24" deep and 6"-18" wide), and local rates. A French drain 30'-50' long might cost $300-$1,500, with prices averaging about $750-$1,250. For example, Galtech.com[1] reports having two French drains installed at an Oregon home for $1,475 for 58' total, about $25-$26 a foot.
French drains can be a do-it-yourself project for those who are willing to dig, or to rent equipment to dig the trench. DoItYourself.com[2] describes the 4" PVC pipe and fittings as relatively inexpensive and easy to work with, and estimates that crushed rock will cost $2-$4 a square foot and renting a compactor at $65-$85 a day. Renting a trencher can cost $50-$80 a half-day or $90-$105 a day, while a small backhoe rents for $150-$200 a day.
Interior French drains are often a last resort when other basement waterproofing methods don't work. They typically cost $2,000-$6,000 but can be $10,000-$15,000 or more with a sump pump and basin. Installation requires cutting/chipping a channel around the perimeter of the basement floor and filling it with gravel and perforated PVC pipe.

Related articles: Dry Well, Rain Garden, Basement Waterproofing

What should be included:

Named for Henry French, who wrote a book on drains in 1859, French drains direct excess water away from a house or soggy area, often into a dry well (an underground structure that allows the water to percolate into the water table) or a rain garden (designed to let the water percolate into the ground or be absorbed by plants).
French drains are typically needed if a property is lower than the surrounding properties or if the home foundation is lower than the surrounding land, to direct the water away from the foundation or to avoid having a permanently soggy area. DoItYourself.com explains how to plan a French drain[3] .
A trench is typically dug along the primary route the runoff water follows, and directs the water into a specific area. The trench must always slope downward (about a 1% grade or 1' for every 100') so the water flows freely and doesn't puddle in the trench. The perforated PVC pipe is laid with the holes facing down to make it harder for silt or gravel to enter the pipe. The pipe may be wrapped inside landscape fabric and/or covered with a fabric pipe sleeve to keep out roots and dirt. EasyDigging.com describes the installation process[4] and DIYNetwork provides a video showing French drain installation[5] .
Check on local, state and federal regulations which may regulate the use of French drains in order to keep contaminants out of the water supply.
Also before digging, call 811[6] ) to have utility companies come out and mark any underground utility lines; or contact local utility companies directly.

Additional costs:

French drains can direct excess water into an open or area, but it might be necessary to add something to hold the water until it naturally percolates into the surrounding soil. A do-it-yourself dry well can cost $5-$50, or $90-$380 for a DIY installation of a prefabricated plastic model; having a concrete drywell professionally installed can cost $300-$5,000 or more. Installing a rain garden can cost $100-$750 for a do-it-yourself project of 150 square feet.

Shopping for a french drain:

Do-it-yourself materials (PVC pipe and fittings, landscape fabric, pipe sleeves, and gravel or crushed rock) are available at most home improvement and hardware stores or plant nurseries.
Professional installation is typically done by a landscaper or gardener familiar with drainage issues, although it can be done by a handyman or day laborer if attention is given to keeping the trench always sloping downward. Check with neighbors with similar drainage problems, or ask for referrals to landscapers and gardeners at local home improvement, hardware or plant nursery centers. A landscaping company lists guidelines for hiring a landscaper[7] .
Get several estimates; verify that the company is properly bonded and insured;and ask for and check references.

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What People Are Paying - Recent Comments

French drains being installed wrong

Amount: $0.00

Posted by: Hugh Mungus in Syracuse, NY.

Posted: April 12th, 2019 09:04AM

you shouldnt be installing french drains from 12-12 inches down - that would be doing it incorrectly. This is coming from someone who worked in the basement waterproofing business and installed these daily.