Why quotes for the same house can differ by $8,000

Three reasons, in order of how often they explain the gap. First, pier count — one company plans piers every 5 feet, another every 8, and only the engineer's elevation map says who's right. Second, pier type — pressed concrete, steel, and helical piers carry different costs and suit different soils; cheaper isn't automatically worse, but you should know what you're buying. Third, scope padding — interior piers, full perimeters, and "preventative" piers on sides that haven't moved. The engineer's report exists precisely to referee all three.

What about the warranty?

Most DFW companies advertise a "lifetime warranty." Read what it actually covers: usually free re-adjustment of their piers if that section moves again — not damage to your house, not other sections, and sometimes not even the labor. A transferable warranty matters when you sell, because foundation history comes up in every Texas transaction. Get the warranty in writing, in the contract, before work starts — never as a verbal promise at the kitchen table.

The order to spend money in

Engineer's report first. Drainage and plumbing checks second — a leaking sewer line under a slab causes more "foundation failure" than soil alone, and no pier fixes a leak. Piers third, sized to the engineer's plan. Cosmetic crack and paint work last, after the house has settled into its repaired position for a season.

City-by-city cost guides

Soil, pier depth, and housing age shift across the Metroplex, and quotes shift with them. See the city guides for Fort Worth, Dallas, Arlington, and Plano.

Why Fort Worth foundations move — it depends which side of town you're on

Fort Worth sits on a transition — your street matters more here than in Dallas.

East Fort Worth is Dallas ground

The eastern edge of Tarrant County is the tail of the Blackland Prairie — deep expansive clay weathered from Eagle Ford shale, the black gumbo builders know well. That clay contains bentonite, which swells when wet and shrinks when dry: swell in the rains, pull away in drought, work the slab like a hinge in between.

Central Fort Worth thins out over limestone

Move west across the Fort Worth Prairie and the clay gets thinner over limestone and marl. Piers may reach firm bearing sooner, which is good. They may also have to drill through rock, which adds labor. Thin clay over rock still moves, but the depth part of your quote can differ sharply from an east-side job.

The far west side changes again

Toward Benbrook and White Settlement you run into sandy Western Cross Timbers soils, with sandstone underneath. Sand moves less than clay, so drainage, erosion, and washout matter more than heave there. A salesman who gives every Fort Worth house the same clay speech isn't looking at your lot.

Then there's the age of the house

Almost every Fort Worth home built before about 1960 sits on pier and beam — concentrated in Fairmount, Ryan Place, Mistletoe Heights, the Near Southside, and parts of Arlington Heights. Pier and beam handles clay well and keeps plumbing accessible. It also means your problem may be a rotted sill, a cracked pier, settled shims, or crawl-space moisture — not a pier-count problem at all.

How to get quotes without getting taken

Does insurance cover it?

Usually, no. Standard policies exclude settling, soil movement, and earth expansion — which covers most Tarrant County foundation problems. The common exception is a sudden covered event, like a burst pipe that washed out soil under the slab. Some Texas policies carry a plumbing-leak endorsement that can help when a leak caused the damage. If plumbing is involved, document everything and ask your insurer before you repair.

How long does the work take?

Most jobs run one to three days. A pier-and-beam relevel is often one to two days; large full-perimeter jobs can run three to five. You can almost always stay in the home — though a pier-and-beam crew will be under it, so plan for noise and keep crawl-space access clear.

Why Dallas foundations move

Dallas sits squarely on the Blackland Prairie. The topsoil is a dark montmorillonite clay — rock hard when dry, sticky when wet, and among the most expansive clays in Texas. The Houston Black series, the Texas state soil, is the textbook example of it. It swells with rain and shrinks hard in drought, so a Dallas slab is never really resting. It is riding a seasonal cycle.

Under that clay, the picture changes. Much of Dallas is underlain by the Austin Chalk — yes, that is the formation name, not the city — with Eagle Ford shale below it. In much of Dallas County that chalk is not far down. In other lots, you go through deep clay first. That variation matters for price:

Where chalk is shallow

Piers reach refusal sooner and the job is simpler.

Where clay runs deep

Piers go further to find stable soil. Steel systems are often proposed here because they can reach deeper bearing strata — 18–30 feet in some North Texas cases, versus roughly 8–12 feet for pressed concrete.

Lot to lot, not just neighborhood to neighborhood

Two houses on the same street can need different depths. Anyone who prices your job without measuring your lot is guessing.

Dallas adds two more local pressures. First, age: many older neighborhoods — Lakewood and Oak Cliff are the familiar examples — were built on pier-and-beam, not slab. Those homes need re-leveling, re-shimming, and sometimes replacement of failed beams and joists from the crawl space. Second, trees: a mature live oak drinking from under one corner of the slab all summer will dry that corner, drop it, and crack it first.

Plano and the north Dallas corridor have their reputation for a reason — same deep, high-plasticity Blackland clay, and movement there is continuous through the year.

How to get quotes without getting taken

Dallas is a competitive market, which helps you — if you make companies compete on the same scope.

Does insurance cover it?

Usually, no. Standard Texas policies exclude settling and earth movement from expansive clay — most Dallas foundation trouble. The exception is plumbing: many Texas policies carry a plumbing-leak endorsement that can cover damage caused by a sudden under-slab leak, even though clay settling itself is excluded. If a leak is involved, document everything before you repair and confirm coverage with your carrier. This is general information, not insurance advice — your policy controls.

How long does the work take?

Most Dallas jobs run one to three days on site. A one-side exterior job is often one to two days; interior piers, pier-and-beam wood replacement, or a full perimeter can push it to three to five. You can almost always stay in the home, though interior work means noise, dust, and moving furniture for a day or two.

Why Arlington foundations move

Arlington's housing stock is the story. A large share of the city was built from the 1960s through the 1980s — ranch-style slab homes that are now 40 to 60 years old. That's exactly the age where decades of clay movement start showing up as cracks, sticking doors, and uneven floors. Older pockets of the city, mostly pre-1960s, are more likely to sit on pier-and-beam foundations, which move and age differently and are priced differently.

Underneath all of it is expansive clay soil, the same black gumbo found across North Texas. It swells when it's wet and shrinks hard when it dries. Arlington's long, hot summers pull moisture out of the soil until the ground drops away from the slab; heavy rains swell it back. Your house rides that cycle every year, and after forty-plus cycles, it shows. Three local factors make it worse:

Mature trees

Arlington's older neighborhoods have big, established oaks and other shade trees — and a large tree drinks an enormous amount of water from under and around a slab. One corner that keeps drying out while the rest of the yard looks fine is often a tree problem, not just a drought problem.

Uneven drainage

Beds settle, mulch builds up, and the slope that originally carried water away from the house quietly reverses over the decades. Water standing against one side of the slab swells that side while the other side stays dry — the house gets worked like a hinge.

Age under the slab

Plumbing in a 1970s home has had fifty years to develop a slow leak. A leak under the slab both erodes soil and swells the clay in one spot. It's often the cause, not a side issue.

None of this means your house is falling down. It means movement in Arlington is normal, ongoing, and mostly a moisture problem — which is why moisture consistency matters more than any single repair. The maintenance playbook covers that side of it.

How to get quotes without getting taken

Foundation repair has honest operators and it has pressure salesmen. Arlington homeowners protect themselves the same way everyone in DFW does:

Does insurance cover it?

Usually, no. Standard homeowners policies exclude settling, soil movement, and earth expansion — which covers most Arlington foundation problems. The common exception is damage caused by a sudden covered event, like a burst pipe that washed out soil under the slab. If plumbing is involved, document everything and ask your insurer before you repair.

How long does the work take?

Most residential jobs in Arlington run one to three days on site. Partial-perimeter work is often a single day; large full-perimeter jobs can run three to five. You can almost always stay in the home during the work. Add time up front for the engineer's visit and any city permit the job requires — the repair itself is usually the fast part.

Why Plano foundations keep moving

Plano sits on the Blackland Prairie, and its clay is the high-plasticity kind — dark montmorillonite clay that swells when wet and shrinks hard when dry. North Texas soil research puts that swell at up to 30% by volume in the active zone, roughly the top five to fifteen feet where moisture changes with the seasons. Your slab sits right on that zone. It is never really resting; it is riding the weather.

East Plano: deep clay

The eastern half of the city is deep Blackland clay, the same heavy expansive soil that causes problems across Collin County. East Plano homes tend to need more piers when they move, because the piers have to travel further to reach ground that doesn't cycle with the weather.

West Plano: chalk near the surface

Toward the west — roughly west of the Tollway — Austin Chalk limestone sits much closer to the surface, with thinner clay over it. Chalk does not swell like clay, so west Plano jobs can be simpler, though thin clay over chalk still moves, and limestone can erode under a foundation over decades.

Then there's the housing stock

Most of Plano was built in the subdivision build-out from the 1970s through the 1990s — slab-on-grade homes now 30 to 50 years old, riding hundreds of wet-dry cycles. Older west Plano neighborhoods from that era often need 10–15 piers when finally repaired, because the movement was gradual enough to ignore for years. The trees planted at move-in are now mature oaks and pecans, drinking from under one side of the slab all summer. Add cut-and-fill subdivision lots, where the ground under one foundation dries at different rates corner to corner, and you get Plano's pattern: not a house that sank once, but a house that keeps creeping.

That is why "continuous movement" is the phrase you hear here. It does not mean your house is falling down. It means moisture consistency, not a one-time fix, keeps a Plano slab quiet.

How to get quotes without getting taken

Plano homeowners get pitched hard — a city full of aging slabs on moving clay is a salesman's market. Protect yourself:

Does insurance cover it?

Usually, no. Standard Texas homeowners policies exclude settling, soil movement, and earth expansion — which covers most Plano foundation problems. The common exception is damage caused by a sudden covered event, like a burst pipe. Many Texas policies carry a plumbing-leak endorsement (form HO-143TX is the common one) that can cover damage caused by an under-slab leak, even though clay settling itself is excluded. If plumbing is involved, document everything and ask your insurer before you repair. This is general information, not insurance advice — your policy controls.

How long does the work take?

Most Plano jobs run one to three days on site. A one-side exterior job is often one to two days; interior piers or full-perimeter work can run three to five. You can almost always stay in the home during exterior work, though interior work means noise, dust, and moving furniture for a day or two. Budget a little extra time for landscaping restoration after the crew leaves.

Why Houston foundations move — and why it's different here

The clay

Much of Houston sits on Beaumont clay — the Gulf Coast "gumbo" — while the western side, including Katy, sits on the older Lissie Formation, a mix of clay, silt, and sand. Beaumont clay is exceptionally reactive, with a plasticity index two to three times the national average. It swells hard when saturated and shrinks hard when dried, and Houston feeds it both extremes: 50-plus inches of rain a year, sometimes 2 to 5 inches in a single afternoon, followed by long, hot drought stretches that crack the soil open feet deep. Your slab rides that heave-and-drop cycle every year — and unlike simple settling, Houston engineers will tell you heave (soil pushing up) is at least as common here as sinking.

The water table and the flat ground

Houston is low, flat, and wet, with groundwater historically close to the surface. Water doesn't run off — it stands. Poor drainage, a downspout dumping at a corner, or a lot that has slowly lost its slope can keep one side of a foundation saturated while the other side dries, and that uneven moisture is what bends a slab.

Subsidence

Parts of the region have literally sunk as groundwater pumping compacted the clay and sand layers underneath — near the Ship Channel, by several feet over the last century. The Harris-Galveston Subsidence District now regulates pumping to slow it, but monitoring in growing suburbs like Katy, Cypress, Spring, and The Woodlands still records measurable sinking — over 14 inches at one Katy station since 2007. Subsidence is permanent, and piers don't reverse it. An engineer can tell you whether your movement is clay cycling, subsidence, a leak, or a mix — the right fix depends on the answer.

The housing stock

Inside the Loop, older pier-and-beam homes in neighborhoods like the Heights and Montrose move differently than slabs: the fix is often re-leveling and re-shimming, and it gets expensive when rot has spread through sills and joists in a damp crawl space. Out in the slab suburbs — Katy, Sugar Land, The Woodlands, and the rest of the ring — homes were often built fast on former farmland and prairie, on the same reactive clay, so age alone doesn't protect them.

How to get quotes without getting taken

Does insurance cover it?

Usually, no. Standard Texas homeowners policies exclude settling, soil movement, and earth expansion, and gradual clay movement is treated as maintenance. The common exception is damage from a sudden covered event, like a burst pipe that washed out soil under the slab — and a flood event by itself doesn't automatically make foundation movement a covered claim. If plumbing or flooding is involved, document everything and talk to your insurer before you repair.

How long does the work take?

Most single-family pier jobs take a few days of actual work — often two to four. The calendar window is usually wider than the workdays: permits, engineer sign-offs, tunneling, drainage work, and the post-lift plumbing test all add days. You can almost always stay in the home during the work.

Why Austin foundations move — and why it depends on your side of I-35

Austin straddles the Balcones Escarpment, and the fault line running roughly along I-35 divides two very different kinds of ground.

East Austin: deep Blackland clay

East of the fault — and out into Pflugerville, Manor, Hutto, and Del Valle — the soil is Blackland Prairie clay, much of it the Houston Black series, the same heavy "black gumbo" that runs down the middle of Texas. Soil-survey data puts shrink-swell in east Travis County ZIP codes at roughly 10–11%, among the highest in the region, and the clay can run 10–20 feet deep. It swells hard when wet and shrinks hard in drought, and movement here is ongoing — not a one-time settling event.

West Austin: thin soil over limestone

West of the fault — Circle C, Bee Cave, Lakeway, Steiner Ranch, and most of Cedar Park and Leander — the soil thins out over Hill Country limestone, and shrink-swell drops to roughly 3% or less. Foundations move far less from soil alone. When west-side homes do have problems, the cause is more often drainage: water running off rock and slope, pooling against the house, or washing soil out from under an edge.

Round Rock straddles the line

The east half sits on Houston Black clay; the west half transitions to shallow limestone soils. Two houses a few miles apart in the same suburb can need entirely different repairs. That's why any Austin quote that doesn't start with what's actually under your lot is a guess.

One more wrinkle: post-tension slabs

Many newer suburban homes sit on post-tension slabs — concrete reinforced with tensioned steel cables instead of rebar. Drilling into one without first scanning to locate the cables is an expensive, dangerous mistake. If your home was built in the last couple of decades and your contractor never mentions scanning, ask about it before work starts.

How to get quotes without getting taken

Foundation repair has honest operators and it has pressure salesmen. Here's how Austin homeowners protect themselves:

Does insurance cover it?

Usually, no. Standard homeowners policies exclude settling, soil movement, and earth expansion — which covers most Austin foundation problems, east side or west. The common exception is damage caused by a sudden covered event, like a burst pipe that washed out soil under the slab. If plumbing is involved, document everything and ask your insurer before you repair.

How long does the work take?

Most residential jobs run one to three days on site. Partial-perimeter work is often a single day; large full-perimeter jobs can run three to five, and west-side rock drilling can stretch a schedule. You can almost always stay in the home during the work — though in peak spring and fall seasons, expect a wait of a few weeks to get on a good crew's schedule.

The pencil-line test

You don't need instruments to know whether a crack is active. You need a pencil, a phone camera, and ninety days.

Signs that matter more than cracks

Cracks are the symptom homeowners notice first, but experienced evaluators weigh other evidence more heavily. Doors and windows are the house's built-in gauges — a frame racked out of square means the structure moved, not just the finish. Stair-step cracking in exterior brick that mirrors a crack inside is a classic pattern. Sloping floors, gaps where walls meet the ceiling, and cabinets pulling away from walls all say the same thing: measure elevations before anyone talks about repairs.

When the answer is an engineer, not a contractor

If two or more "call a pro" signs are present, skip the free-estimate circuit and hire a licensed structural engineer first ($500–$1,000 in DFW). Contractors' free evaluations are sales calls; some are honest, some aren't, and a worried homeowner can't easily tell which. The engineer's elevation survey settles it with numbers.

Slab-on-grade

How it's built. A concrete slab — usually 4–5 inches thick, thickened at the edges into grade beams — is poured directly on the ground, reinforced with rebar or post-tension cables. Plumbing and drains run underneath it, buried in the soil before the pour. Most Texas homes built from the 1960s onward sit on a slab.

How it fails in clay. The slab moves with the soil at its edges. When the perimeter clay dries and shrinks, the edges lose support and settle; when it swells after rain, edges can heave. The center of the slab, where soil moisture stays stable, often stays put — so the foundation bends. A second, quieter failure is the plumbing leak: a sewer or water line under the slab leaks, washes out or oversaturates the soil, and one section drops.

How it's fixed. Piers are installed around the settled section — pressed concrete, steel, or helical — driven or drilled down to stable soil or rock, then the slab is lifted back toward level and supported on them. Interior piers require tunneling under the house or breaking through the floor, which is why interior work costs more. Foam or mud injection can fill voids under a slab but doesn't add structural support where soil has lost bearing.

Typical cost. $600–$1,000 per pier; most one-side repairs run $6,500–$14,000. See the DFW cost guide for the full table.

Pier-and-beam

How it's built. The house sits on a grid of individual piers — concrete blocks, poured concrete, or older cedar posts — that carry wooden beams and floor joists, with a crawl space (usually 18–36 inches) between the floor and the ground. Common in Texas homes built before the 1960s, and still used on sloped lots.

How it fails in clay. Individual piers settle or tilt as the soil beneath them shrinks, so floors slope toward the weakest pier instead of the whole foundation bending. The crawl space adds its own problems: wood beams and joists rot or draw termites when moisture collects, and the shims used to level floors crush or slip over decades. The good news: it's all reachable.

How it's fixed. A crew works from the crawl space: rotted beams are sistered or replaced, settled piers are rebuilt or supplemented, and the floor is re-leveled with shims and jacks. No floor tear-out, no tunneling — which is why pier-and-beam leveling usually costs less than comparable slab work, and why plumbing repairs under these homes are far simpler.

Typical cost. Leveling runs $3,500–$10,000 depending on how many piers and beams need work.

Red flags — walk away when you see these

Contract checklist — before you sign

Every item below should appear in writing in the contract or attached scope of work. If one is missing, ask for it in writing; the reaction tells you plenty.

Water during drought — yes, water your foundation

In a Texas dry spell, soil can pull visibly away from the slab edge, leaving a gap you can fit fingers into. That gap means the perimeter has lost support. A soaker hose run 12–18 inches out from the foundation, a few times a week during drought, keeps the soil against the house from drying out completely. You're not trying to soak the yard — you're trying to keep the moisture level near the slab roughly even, all the way around, all year.

Move water away the rest of the time

The other half of the problem is too much water in the wrong place. Ground should slope away from the house — a drop of about 6 inches over the first 10 feet is the usual target — so rain runs off instead of ponding at the foundation line. Downspouts should discharge at least 5 feet from the house, not dump roof water (a roof collects a startling amount) right at the slab edge. Where drainage can't be fixed with slope, a French drain or surface drain, $1,200–$5,500 installed, is often the repair that makes piers unnecessary. The drainage section covers the whole subject — what it costs, which system does what, and how to run it on clay soil.

Gutters are foundation equipment

Overflowing gutters pour a curtain of water exactly where you least want it: the foundation perimeter. Keep them clean, keep them pitched toward the downspouts, and fix separations at the corners. It is the least glamorous and highest-value maintenance on this page.

Watch the trees

A mature tree drinks enormous amounts of water, and its roots go where the moisture is — including the soil under the edge of your slab. A large tree planted close to the house dries the soil on one side, season after season, and that one-sided drying is a classic cause of one-sided settling. As a rough rule, large trees belong at least their mature height away from the foundation; where a big tree is already close, consistent watering on that side and, in some cases, a root barrier are the practical answers. Get an arborist's read before removing a tree — removal changes soil moisture too, and the soil re-swells over following years.

Plumbing leaks: the hidden cause

A slow sewer or water leak under a slab saturates or washes out soil continuously, and it mimics foundation failure — because by the time you see cracks, it has caused one. A water bill that creeps up unexplained, a spot in the floor that's warm, or one area of the yard that's always green in a drought are all worth a leak test. If you're having foundation evaluated, ask whether a plumbing test is warranted before piers are planned; piers installed over an active leak are money into a hole.

The annual checklist

Twice a year — early spring and late summer, when Texas weather swings hardest — walk this list. It takes half an hour.

Why water decides whether a foundation lives or dies

Ask an engineer what actually moves Texas foundations, and the answer is rarely "the house." It's the moisture content of the clay under it — and moisture is a drainage story. Roof water dumped at the slab edge, a yard that slopes toward the house instead of away, a flowerbed that stays soaked while the opposite side bakes: that is the machinery behind almost every crack on this site.

Piers answer the symptom — they hold the house up from below. Drainage answers the cause. Sometimes drainage is the whole repair. Sometimes it's what makes a pier job last instead of failing in five years. Either way, it is the cheapest foundation work there is, and it is the half most sales pitches skip — because a company that sells piers has little reason to talk you out of them with a $3,000 drain.

Two Texas water problems, two opposite answers

"Texas drainage" is not one problem. Which regime your house sits in decides what a correct system even looks like.

The drainage guides

What whole jobs total

Per-foot math only means something against real project shapes. These are the totals Texas homeowners actually sign for:

Component prices

Most systems are assembled from the same parts. Know what each part costs and a quote stops being a mystery number.

What actually drives the price

Linear feet and depth. More trench, more money — and deeper trench in clay is slower trench. Soil and rock. DFW gumbo digs slow; Austin limestone digs slower, sometimes with a rock saw or hammer on the invoice. The discharge point. A drain that can't empty is a buried water trough. Every system ends somewhere — curb, street, easement, pop-up emitter — and the distance and legality of that endpoint is real money. Access and restoration. Fences, decks, concrete crossings, and putting the yard back (sod, beds, sprinklers) are line items whether the quote admits it or not.

Before you compare any of this to a pier quote

A full-yard drainage system at $5,000–$12,000 competes directly with a one-side pier job at $6,500–$14,000 — and on a house whose movement is water-driven, the drain is the repair and the piers are the decoration. If you're holding both kinds of quotes, work the diagnostic before you decide which problem you're actually paying to fix. Foundation numbers live in the DFW cost guide.

Quote red flags

The test that settles it: an elevation survey

Opinions are free at a sales appointment and worth about that. A licensed structural engineer measures floor elevations across your house — a grid of numbers, typically for $500–$1,000 — and the numbers end the argument. If elevations are essentially level and your signs are seasonal, you have a water problem and a monitoring plan. If one corner is down an inch and the cracks agree, that's structure. This is the same engineer-first rule as the rest of this site, and it matters even more here, because both trades that come after — pier companies and drainage companies — will happily diagnose your house as whatever they sell.

Why piers installed over bad drainage fail

Piers hold the house up. They do not stop the water. Roof water still ponds against the slab, soil between the piers still heaves when wet and shrinks when dry, and the movement the piers were meant to end keeps working on everything the piers don't touch. The symptom: companies returning season after season to "adjust" piers under a house whose real problem was never addressed. Any pier proposal for a house with obvious ponding, negative grade, or downspouts dumping at the slab should include the water fix — or a written reason it doesn't need one.

And sometimes drainage alone is the whole fix

Early, moisture-driven movement often simply stops when the water is managed: regrade the low side, extend the downspouts, drain the ponding area — then run the pencil-line test from the crack check for a full season. If the lines hold, you bought the repair for drainage money instead of pier money, and the clay-soil playbook is the plan to follow. If they keep splitting, the survey numbers will show it, and pier quotes can be compared against a real diagnosis.

What each fix costs

Price both before choosing either. Drainage: $25–$55 per foot for a French drain in DFW, $2,500–$5,000 for a single problem area, $5,000–$12,000 for a full-yard system. Foundation: $600–$1,000 per pier, $6,500–$14,000 for one side of a slab home. The engineer ($500–$1,000) is cheaper than either mistake.

The decision flow

How a French drain works

A French drain is a trench below the surface: lined with filter fabric, filled with washed gravel, with a perforated pipe at the bottom. Groundwater and saturated soil seep into the gravel, drop into the pipe, and the pipe — set on a slope — carries the water to a discharge point. You never see the water it moves, because its whole job happens in the soil. It solves: a side yard that never dries out, water migrating through the ground toward the house, chronically saturated soil against the foundation.

How a surface drain works

A surface drain sits at grade and catches runoff before it ponds. Catch basins — grated boxes set in the yard — take water in the top; channel drains do the same job in a line across hard surfaces. Solid, non-perforated pipe carries what they catch to the discharge point. It solves: puddles and sheet flow, runoff off roofs, drives, and slopes, low spots where water collects and stands.

Channel drains: the hardscape answer

Water on concrete can't soak in — it can only run. When a driveway or patio slopes toward the garage or the house (and a surprising number do), the fix is a channel drain: a narrow grated trench set across the apron, patio edge, or pool deck that intercepts the sheet of water and pipes it away. If your problem appears on pavement rather than in soil, this — not a French drain buried in the lawn — is the tool.

Built for Texas clay: three specs that decide whether it lasts

Fabric-wrapped, washed gravel

Clay sheds microscopic fines that migrate into anything buried in it. A French drain in Texas clay needs clean, washed gravel (not cheap crusher run full of dust) with the trench wrapped in filter fabric, so soil water gets in and clay stays out. Skip either and the drain silts up from the outside in.

Schedule 40 PVC over corrugated pipe — in shrink-swell clay

The black corrugated flexible pipe is cheap and easy to lay, and on forgiving soil it's fine. Texas clay is not forgiving soil: it moves, season after season, and corrugated pipe crushes, bellies, and traps sediment in its ridges. Smooth-wall Schedule 40 PVC holds its slope through the movement, resists root intrusion better, and can be augered or jetted clean years later. In shrink-swell clay, spec PVC. If a bid defaults to corrugated, ask why — in writing.

Hold the slope

A drain line needs roughly 1% fall — about an inch every 8 feet — all the way to discharge. On clay that swells and shrinks, a low spot in the line becomes a permanent sediment trap. This is the real argument for rigid pipe: it's the slope, preserved, that does the work.

Most Texas yards end up with both

The systems are complements, not rivals. The common correct design: surface drains take the roof and pavement water before it ever reaches the soil, and a French drain along the house side handles the soil water that's left. The question to answer first isn't which system — it's which water you have. The diagnostic sorts that out, and the cost guide prices both.

First, understand what clay does to water

Sand lets water pass; clay mostly refuses. Rain that lands on Texas clay runs off, ponds, or sits in the top few inches until it evaporates — and a dry well buried in gumbo clay is a bathtub, not a drain. So every working Texas system does the same thing: catch water at the surface or in a gravel trench, put it in a pipe, and carry it on a slope to a place it's allowed to be. Any design whose last step is "and then it soaks in" deserves suspicion.

Step one is the roof: gutters and downspout extensions

Before any trench is dug: your roof is the largest water collector on the lot, and a single downspout can dump hundreds of gallons at one corner of the slab in one storm. Gutters should be clean, pitched to the downspouts, and big enough for Texas rain. Every downspout should discharge at least 5 feet from the house — with an extension across the flowerbed, or better, piped solid underground to the system's discharge point. This is the cheapest drainage work there is, and on many houses it's half the problem. (It's also step one of the foundation maintenance routine — same water, same house.)

Step two is the ground: grade away from the house

Soil should fall away from the foundation — a drop of about 6 inches over the first 10 feet is the usual target — so rain runs off instead of ponding at the slab line. Mind the swale: that shallow channel most suburban lots share along the side line is the neighborhood's drainage, and building it up with beds, edging, or fill dams water against your house and your neighbor's. Regrading a swale runs $800–$3,000 and is often the only "drain" a lot needs.

Step three: build for your regime

Dallas–Fort Worth — balance, not maximum dryness

Shrink-swell clay punishes extremes. A drain system that strips every drop of water from one side of the house while the other side stays wet manufactures the uneven moisture that cracks slabs. DFW systems collect the excess — ponding, runoff, saturated spots — and move it off, while the soil against the foundation stays roughly as moist as the soil everywhere else. Pair it with the drought-watering routine in the maintenance playbook: drainage handles the surplus; watering handles the deficit.

Houston — capacity and speed

On flat gumbo with 50-plus inches of rain, the risk isn't a dry side — it's water arriving faster than it can leave. Houston systems need generous surface capacity (more basins, wider channels), slope verified everywhere, and sump pumps with battery backup where the lot can't fall to the street. Design for the storm that stalls over the city for two days, because it will.

The neighbor rule: Texas Water Code §11.086

You may drain your land. You may not make your neighbor pay for it. Under Texas Water Code §11.086, a landowner who diverts surface water in a way that damages neighboring property can be held liable for that damage. In plain terms: water your system collects has to go to the street, a drainage easement, or the natural drainage path — not piped over the fence line, and not concentrated onto the lot next door. A contractor's discharge plan should name the destination out loud. "Where does this water end up?" is a legal question, not just an engineering one.

Permits, HOAs, and the storm system

Tying a private drain into the municipal storm system, or cutting the curb to discharge through it, generally requires city approval — rules vary by city, and unpermitted tie-ins get removed. HOAs commonly restrict discharge points and any work inside drainage easements, and many require approval before you dig at all. And whatever the paperwork says: call 811 before any trenching. It's free, it's the law, and sprinkler lines are the least of what's buried in a Texas yard.

The annual checklist

Drainage fails slowly and invisibly. Once a year — late winter, before the spring rains — walk this list.