What a french drain actually does
A french drain is a gravel-filled trench with a perforated pipe inside. Water seeps into the gravel, enters the pipe, and gets carried away from the area where it is causing problems. The name sounds specialized, but the concept is straightforward: give water a preferred path so it stops finding its own.
There are two main versions. An exterior french drain sits outside the foundation wall, intercepting groundwater before it reaches the basement. An interior drain tile system sits inside the basement, along the perimeter of the floor, and captures water that has already entered the wall before it spreads across the floor. A contractor may suggest one or both depending on the situation.
Why drainage problems are common here
Omaha sits on loess, a fine wind-blown silt, with clay-rich subsoils that move with moisture. The city engineer has noted that loess can be easily carried away by water, leaving behind gaps underground. When water saturates that soil, it builds pressure against foundation walls and finds any available path inside.
Omaha averages about 31.86 inches of precipitation a year, with May the wettest month. In March 2019, frozen ground sent rain and snowmelt running off the surface rather than soaking in, contributing to record flooding across the region. Bellevue and Offutt were hit especially hard. Yards and foundations that were not draining well before that event had no chance during it.
Surface drainage: the first thing to look at
Before any underground work, a contractor will usually look at what is happening above ground. Gutters that are clogged or downspouts that discharge right next to the house send large volumes of water directly to the foundation. Downspout extensions that carry water several feet away from the house are a simple starting point.
Grading matters too. The ground around a foundation should slope away from the house. Settled soil, dense mulch beds, or added landscaping can reverse that slope over time, directing rain toward the wall instead of away from it. Regrading is sometimes all a yard needs.
Where the water should go
This is an important detail. A french drain or interior system has to discharge somewhere. Most cities in the Omaha metro do not allow sump water to be routed into the sanitary sewer. Your contractor should route discharge outside, away from the foundation and neighboring properties, to a suitable outlet.
If your home is in one of the older parts of Omaha on the combined sewer system, this is especially worth discussing. Some older homes have drainage that was originally connected to the sanitary line, which can cause problems during heavy rain.
What affects the cost
Drainage projects vary widely depending on the length of trench needed, whether the work is exterior or interior, how much excavation is involved, whether a sump pump is part of the system, and the condition of the existing soil and foundation. Exterior work generally involves more labor and disruption than interior drain tile. Ask your contractor to explain exactly what is included and what happens to the excavated material and landscaping.
How to choose a contractor
Nebraska requires contractors to register with the Nebraska Department of Labor. You can search by name, city, or ZIP at dol.nebraska.gov. The state notes that registration does not ensure quality of work, so also check the BBB of the Midwest Plains, which is based in Omaha. Ask any contractor to explain where the water is currently coming from, what their system will do with it, and where it will discharge. Get everything in writing.
Frequently asked questions
What is the difference between a french drain and drain tile?
The terms are often used interchangeably, but drain tile typically refers to an interior perimeter system installed at the base of the basement wall, while a french drain more often refers to an exterior trench. A contractor may use either term, so ask them to describe exactly where the pipe will be and where the water will go.
Will a french drain fix a wet yard even if my basement is dry?
Yes. Surface french drains are also used in yards that pool after rain, regardless of whether the basement is affected. If your yard stays soggy for days after a storm, a drainage contractor can assess whether a trench system would help move that water off the property.
Do I need a permit for this work?
Structural repairs and new egress windows usually need a city permit, but drainage work varies. A good contractor will know what your city requires and should pull any necessary permits for you. If you are not sure, check with your city.
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