French Drain Installation in Waco, TX

Yard staying soggy against the house? Free on-site inspection: (254) 503-5077

A French drain is a gravel-filled trench holding a perforated pipe that collects water from inside the soil and carries it by gravity to a lower outlet. In Waco a typical run costs $1,500-$6,000, about $25-$60 per linear foot, and installs in 1-3 days. Built right – washed stone, non-woven fabric, 1/8 inch of fall per foot minimum – it should run 20 years or more in Blackland Prairie clay.

Written by the Brazos Foundation Repair team – 10 years repairing foundations in Waco & Central Texas.

Last updated: September 2026

Quick answers

Cost: $1,500-$6,000 for most Waco homes, or $25-$60 per linear foot.
Timeline: 1-3 days; add a day if the clay is too wet to trench.
Cause: subsurface water sitting in low-permeability clay against the foundation.
Warranty: drainage work carries a written workmanship warranty.
Insurance: drainage upgrades are rarely covered; read your policy.

What is a French drain, and how is it different from a surface drain?

A French drain is a sloped trench lined with filter fabric, bedded in washed gravel, and fitted with a perforated pipe that collects water already inside the soil and moves it to a lower discharge point. It works below grade, on water you cannot see.

A surface drain handles water on top of the ground. A curtain drain, or interceptor, is the same build set across the uphill flow path.

Drain type	What it collects	Typical Waco use
Surface / channel drain	Ponded water on lawn or drive	Low spot holding water after a storm
French drain	Water inside the soil profile	Clay staying saturated against the slab
Curtain / interceptor drain	Water flowing toward the house	Lot falling from back fence to home

What is actually in the trench?

Six parts; skipping one is why cheap drains fail.

Depth: 18-24 inches for a yard run, 24-36 inches foundation-side, never below the bottom of the grade beam.
Width: 8-12 inches, one trencher wide; depth does the work.
Fall: 1/8 inch per foot (1 percent) minimum, 1/4 inch preferred – 7.5 to 15 inches of drop over 60 feet, shot with a laser.
Washed gravel: angular 3/4-inch to 1-1/2-inch clean stone, three inches under the pipe and 8-12 inches over it. Pea gravel and crusher run choke.
Perforated pipe: 4-inch rigid PVC laid holes down, so it fills from below and empties completely. We skip pipe socks; clay fines blind them fast.
Non-woven geotextile: 4-6 ounce, wrapped burrito-style around the stone with a 12-inch overlap. Keeping silt out of the stone keeps the drain alive.

Cleanouts go at both ends, every bend, and every 50-75 feet – the only way to jet the line.

Where does a French drain belong on a Waco lot, and where does it not?

It belongs 3 to 8 feet out from the foundation, on the side where water arrives or lingers, running to the lowest corner of the lot. Most homes here need one or two sides, not a full perimeter.

Good lines: the uphill side of a falling lot, a shaded side that never dries, the edge of a patio that sheds sheet water.

Poor lines: hard against the grade beam, inside a tree’s root plate, or any run ending uphill of the water it collects. Where the clay itself is the problem, soil stabilization and a root barrier do more.

Not sure which side needs it? Call (254) 503-5077.

How do you solve the outlet on a flat lot?

Waco, Hewitt, and Robinson are full of near-flat Blackland lots with no low point. Four options, best first.

Daylight outlet. Where grade drops 12 inches or more on the property, the line pops out at a rodent-guarded grate.
Pop-up emitter. A spring-loaded lid flush in the lawn, for fall without a visible bank.
Dry well. A gravel pit or chambered basin. Honest limit: Blackland clay percolates slowly, so a dry well is storage, not disposal.
Sump basin and pump. With no fall at all, a pump lifts water to the street or easement.

Start shallow at the house and deepen toward the outlet – that is how you manufacture fall. Curb discharge is allowed in some spots and not others, so we check City of Waco rules first, and never aim an outlet at a neighbor’s lot.

How is a French drain installed, step by step?

Inspect and lay out. Walk the lot after rain, shoot elevations, mark the line and outlet, call 811.
Trench and set fall. Cut 8-12 inches wide to depth, bottom graded to a continuous 1/8 to 1/4 inch per foot.
Line the trench. Lay non-woven geotextile, leaving width both sides to fold over later.
Bed the pipe. Three inches of washed stone, then 4-inch perforated pipe holes down, re-checked for fall.
Backfill with stone. Washed gravel to within 4-6 inches of grade, cleanout risers set.
Close the wrap and outlet. Fabric folded over with a 12-inch overlap, solid pipe running to a guarded outlet.
Cap, test, restore. Topsoil and sod back, then a hose run into the high end and watched at the outlet.

Wet weather adds a day: saturated Blackland clay slumps into an open trench.

What does a French drain cost in Waco?

Length, depth, and access set the price.

Scope	Typical length	Typical Central TX range
Short yard run, easy daylight outlet	20-40 ft	$1,200-$2,500
One side of the house, standard depth	40-60 ft	$2,200-$4,000
Two sides or a wrapped corner	60-100 ft	$3,500-$6,500
Long interceptor plus outlet work	100-150 ft	$6,000-$12,000
Sump basin and pump for a flat lot	added	$900-$2,200
Hand-dig through beds or hardscape	added	25-60 percent

Disclaimer: figures are typical Central Texas market ranges. Your exact price is set after a free on-site inspection.

Bundling drain and pier work beats two mobilizations – see foundation repair cost. Drainage carries a written workmanship warranty; pier work carries the tiered, transferable lifetime terms on the warranty page.

How long does a French drain last, and what clogs it?

Washed stone, non-woven wrap, rigid pipe, and real fall buy 20 to 30 years. Pea gravel, a sock, and no fabric can plug in 5. Four failure modes cover nearly all of it.

Silt infiltration: fines migrate in and cement the stone shut, from torn fabric or unwashed gravel.
Fabric blinding: clay particles pack the geotextile face until water stops passing.
Roots: willow, sycamore, and cottonwood roots follow moisture into perforations and joints.
Crushed pipe: thin corrugated pipe collapses under a drive, a trailer tire, or a track machine.

How do you maintain a French drain?

Twice a year, ten minutes: clear grass, mulch, and silt off the outlet grate and check the pop-up still opens. After a long storm, water should leave the outlet within an hour of the rain stopping.

Every 3-5 years, or sooner if flow slows, have the line jetted from the cleanouts. Keep trees, raised beds, and sprinkler trenching off it.

When is a French drain the wrong answer?

We turn this job down regularly.

Bad grading is the real problem. Regrading to roughly 6 inches of fall in the first 10 feet costs a fraction of a trench.
Downspouts dump at the wall. Extending them 6-10 feet solves more soggy yards than any drain.
An under-slab plumbing leak. Water coming from inside is never caught by an exterior drain; static and hydrostatic testing comes first.
A city or neighborhood drainage issue. Water crossing from a street, easement, or upstream lot is a municipal matter first.
The foundation has already moved. A drain stops the cause but lifts nothing. If you see the signs of foundation problems, repair comes first.

Regrading, downspouts, and surface drains sit on the drainage solutions page.

Where do we install French drains in Central Texas?

Across McLennan and Bell counties: Waco, Woodway, Hewitt, Robinson, Bellmead, McGregor, China Spring, Lorena, and Temple. Blackland Prairie clay behaves differently on the Brazos and Bosque river terraces than west toward the Balcones Fault zone, and the USDA NRCS soil survey and Texas A&M AgriLife Extension map those units: and . The structural overview starts at foundation repair in Waco, TX.

Frequently asked questions

How deep should a French drain be in Waco clay? Yard runs go 18-24 inches deep, foundation-side runs 24-36 inches, always above the bottom of the grade beam.

Which way do the holes in the pipe face? Down. Water enters at the bottom of the stone envelope, so holes-down lets the pipe fill from below and empty completely.

Do I need fabric, or can I just use gravel? Fabric is what makes the drain last. Without a non-woven wrap, clay fines migrate into the stone and the trench silts closed.

Can a French drain work on a flat lot with nowhere to drain? Yes. Start shallow at the house, deepen toward the outlet, and end at a pop-up, a dry well, or a sump and pump.

Will a French drain fix my foundation? It removes the water driving the clay movement, but lifts nothing already settled. Settled homes need piers; the drain protects that repair.

How much does a French drain cost per foot in Waco? Roughly $25-$60 per linear foot machine-trenched, and $60-$100 where it must be hand-dug through beds or hardscape.

Ready to get water out from under your house?

The inspection is free. The quote names trench length, depth, stone and pipe spec, and where the water goes.

Call Brazos Foundation Repair at (254) 503-5077 or email info@brazosfoundationrepair.com.

Disclaimer: figures are typical Central Texas market ranges. Your exact price is set after a free on-site inspection.