A French drain is a trench filled with stone, usually around a perforated pipe, that collects water underground and carries it to an outlet, and you need one when water cannot be moved off the yard by regrading alone. On Michigan clay the outlet decides whether it works, so the plan starts with where the water can physically and legally go.
What a French drain is
A French drain is simple in principle. A trench is dug along the path where water collects or needs to be intercepted. It is lined, often with a filter fabric, and a perforated pipe is laid in the bottom with a steady fall toward the outlet. The trench is filled with clean stone, and the top is finished with stone or soil and grass.
Water moving through the ground finds the stone, drops into the pipe and runs downhill to the outlet. Unlike a swale, which moves surface water in a shallow open channel, a French drain works below the surface. That makes it useful where water is coming up through the ground or seeping across the yard, rather than just running over the top of it.
When grading is enough, and when it is not
Many wet yards do not need a French drain at all. If water is standing because the yard is flat or slopes back toward the house, regrading so it sheds water is usually the simpler and more lasting fix. That is why the first look at any drainage job is at the grade, and our guide to yard drainage on clay soil covers those causes.
A French drain earns its place when the surface cannot be shaped to move the water: a yard that is lower than everything around it, water seeping from a neighbor's higher ground, a wet strip at the bottom of a slope, or water collecting along a foundation, a patio or a driveway edge. It is also used when a swale would cut through a space the owner wants to keep usable.
The outlet decides everything
A drain with nowhere to go is just a buried trench full of water. The outlet might be a point where the pipe daylights on lower ground, a roadside ditch, or an approved connection to a county drain. On flat Thumb ground, finding enough fall to reach any of those is often the hardest part of the design.
Several of those outlets belong to someone else. A road ditch is under the county road commission or MDOT, and the St. Clair County Road Commission requires a permit for work within the public right-of-way. The St. Clair County Drain Commissioner lists a permit for any new discharge into a county drain; Lapeer County has its own drain commissioner, and in Macomb County drains are handled by the Public Works Office. A natural stream is a matter for EGLE. Ask the right office before the pipe goes in, and avoid sending the water onto a neighbor's property.
Stone, fabric and pipe on clay soil
Clay is the reason French drains fail early in this part of Michigan. Fine clay particles move with the water and, over time, can fill the gaps in the stone and silt up the pipe. A filter fabric around the trench or the pipe helps keep the soil out while letting water through. Clean, washed stone matters for the same reason: stone with a lot of fines in it plugs up faster.
The fall of the pipe matters too. Too little and the water sits in it and drops its silt; laid uneven and it holds water in low spots. A cleanout at the high end makes it possible to flush the line later. None of these details are visible once the trench is covered, which is why it pays to ask how the drain will be built, not only where it will go.
MISS DIG and what is in the way
A French drain is a dig, so MISS DIG 811 comes first. MISS DIG says you reach it by calling 811 or filing a request online, that you should make sure a hired contractor makes the contact, and that work cannot begin before the start time on the locate request even if everything has been marked. See our MISS DIG guide for more.
MISS DIG marks public utility lines. A drain trench across a yard often meets private lines that it does not mark: a sprinkler system, a buried feed to a garage, a line to a pool or yard light, a well line. Tell your contractor about anything you know is buried, and expect the route to bend around what turns up.
Near the house: downspouts and sump lines
A lot of yard water starts at the house. Downspouts that empty right at the foundation, or a sump pump that discharges into the side yard, can keep the ground soaked no matter how good the grade is. Burying downspout lines and carrying them out to the drain or to a daylight outlet often solves the problem at the source.
Sump pump discharge is a separate question with its own rules. Where it may go, and whether it can tie into a storm system or a county drain, is up to the township or city and the drain office. Check with them before connecting a sump line to any new drain. Water standing against a foundation is the expensive kind of wet yard, so the area around the house gets looked at first.
Getting a French drain installed or repaired
Elite Excavating installs French drains, buries downspout lines, cuts swales and handles culverts and ditch work, and it also repairs older drains that have plugged or collapsed. See the drainage solutions page for what that covers, or the Lapeer County drainage page if your property is there.
The estimate starts with where the water comes from and where it can go. Sometimes the answer is grading alone, and you will be told that rather than sold a drain you do not need. When a drain is the right fix, George lays out the route, the outlet and the fall before any digging. Call (989) 702-2426 for a free on-site estimate around Capac and the St. Clair, Lapeer and Macomb County towns.
The Short Version
- Try regrading first; a French drain is for water the surface cannot shed.
- The outlet decides whether a drain works, so plan it before the trench.
- Road ditches, county drains and streams each have an owner: road commission or MDOT, drain office, EGLE.
- On clay, filter fabric, clean stone and a steady fall keep the drain from silting up.
- Contact MISS DIG 811 first and point out private buried lines.
Quick Answers
Do I need a permit to install a French drain in Michigan?
It depends on where the water goes. Tying into a county drain needs the drain office: in St. Clair County the Drain Commissioner lists a permit for any new discharge. Work in a road ditch needs the road commission or MDOT, and a natural stream needs EGLE. Your township may have its own rules, so ask before you build.
How do I know if my French drain is clogged?
Common signs are water standing over the drain line after rain, a wet strip where the yard used to dry out, or no water coming out of the outlet when the ground is soaked. Older drains without filter fabric often silt up. A cleanout can sometimes be flushed; a collapsed or plugged section usually has to be dug up and replaced.
Does a French drain work in clay soil?
Yes, when it is built for clay. Clay drains slowly and its fine particles can plug the stone and pipe, so filter fabric, clean stone and a well-graded pipe matter more here than in sandy soil. The outlet also has to be lower than the drain, which on flat ground takes careful planning.
Can a French drain run along a property line?
It can, and it is a common spot for one, especially where water comes from a neighbor's higher ground. Know where the line is before digging, keep the work on your side, and make sure the outlet does not send water onto someone else's property. Your township office can tell you about any local rules.
See the drainage service or call (989) 702-2426.