Drainage and Grading: Keeping Water Away From Your Amarillo Foundation

Published October 26, 2026

We've written about the dry half of the foundation problem: in a hot Panhandle summer, the clay around a slab shrinks away and the edge loses support, which is why steady watering matters. This is the other half: the water you don't want, arriving all at once, in the wrong place.

Amarillo averages only about 20 inches of rain a year, and roughly three-quarters of it falls between April and September, mostly in thunderstorms. So rain here doesn't soak in gently over a week. It arrives as a downpour on flat ground and dense clay that can't absorb it fast enough, and it goes wherever the yard sends it. If the yard sends it toward your slab, the foundation pays for it.

Why Drainage Matters So Much on Panhandle Clay

The soils under most Amarillo homes, Pullman clay-loam and its neighbors, swell when they get wet and shrink when they dry. A foundation can live with that as long as the moisture change is even all the way around. Trouble starts when one part of the house gets far more water than the rest:

• One corner swells. A downspout that dumps at the same corner every storm keeps that clay wetter than the soil under the rest of the slab. That corner can heave while the rest of the house doesn't.
• The soil softens. Clay that stays saturated loses bearing strength, so the edge of the slab can settle into it.
• Soil washes out. Water running along a slab edge carries soil with it, leaving voids under the beam.

Drainage and watering aren't opposites. They're the same goal: keep the soil moisture around the house steady. Drain storm water away fast, then add slow, controlled water in dry spells.

Check #1: Which Way Does the Yard Slope?

Ground next to a house should fall away from it. Modern building codes generally call for the grade to drop at least 6 inches within the first 10 feet of the foundation. Where a lot is too tight for that, a shallow swale (a gentle, grassy channel) should carry water around the house instead.

Plenty of older Amarillo yards don't meet that anymore, even if they did when the house was built. Flowerbeds get built up, sod gets laid on top of old sod, and soil settles next to the slab, leaving a low spot right where you don't want one.

How to check without special tools: drive a stake at the foundation and another 10 feet out, tie a string between them, and level it with a line level from the hardware store. Measure from the string to the ground at the far stake. Six inches or more is good. Less than that, or a string that sits closer to the ground at the house end, means the yard is sending water toward the slab.

Even simpler: walk outside during or right after a real rain. Water standing against the foundation, or a muddy strip along one wall that stays wet for days, tells you where the problem is.

Check #2: Gutters and Downspouts

A roof collects a surprising amount of water. On a 2,000-square-foot roof, one inch of rain is roughly 1,200 gallons, and the gutters deliver it to a handful of spots. Where those spots are decides a lot.

• Downspouts should discharge several feet from the house, ideally 5 to 10, onto ground that slopes away. A downspout that ends at the slab with a splash block is better than nothing, but not by much.
• Check buried downspout lines. Underground drain pipes are tidy, but they clog with leaves and grit and then back up silently right at the foundation. Run a hose into the downspout and confirm water comes out the far end.
• Clean the gutters. Overflowing gutters drop water along the whole wall. Panhandle dust, leaves and shingle grit fill them faster than people expect, and hail can dent and pull them loose.
• No gutters at all? Many Amarillo houses don't have them. Then the drip line under the eaves is your problem area. Look for erosion along it, and make sure the ground there slopes away.

Check #3: Flowerbeds and Landscaping

Landscaping causes more drainage problems against Amarillo slabs than almost anything else, usually with good intentions:

• Edged beds hold water against the house. Brick or stone borders built around a bed can turn it into a basin that keeps the soil soaked next to the beam.
• Beds built up too high. Keep soil and mulch below the top of the slab, with some concrete showing. Soil packed up to the brick or siding traps moisture and invites termites.
• Heavy watering in beds next to the house. A thirsty flowerbed against the foundation creates exactly the uneven moisture you're trying to avoid.
• Trees close to the slab. Large trees draw water out of the clay in summer, the opposite effect, but still uneven. Our clay soil guide covers how roots and soil interact.

Check #4: Sprinklers and Other Hidden Water

• Sprinkler heads spraying the foundation. Turn each zone on and watch it. Heads aimed at the house, or a broken head bubbling next to the slab, add water in the worst spot.
• Leaking valves or lines. A spot in the yard that's always green or soft may be a leak, not a happy patch of grass.
• The AC condensate line. In summer an air conditioner can drip a few gallons a day. If the line ends at the slab, move it.
• Hose bibs and pools. A dripping faucet or a leaking pool next to the house adds water one spot at a time.
• Under-slab plumbing. Not every wet spot comes from outside. If the soil stays wet with no obvious source, read slab leak or foundation problem?

Check #5: Driveways and Patios

Concrete next to the house should slope away from it too. When a patio or driveway settles and tips back toward the house, it collects runoff and delivers it straight to the slab edge, often through a joint that's opened up. Our slab leveling guide covers lifting sunken flatwork and sealing the joints so rain can't wash the fill back out.

What Drainage Fixes Cost

Many drainage fixes are cheap. Some are not. Typical Amarillo-area work:

If you're getting foundation repair bids, drainage should be part of the conversation. A bid that lifts the slab without addressing water standing against it is fixing the symptom. Our foundation repair cost guide and bid checklist show how drainage fits into a complete repair.

Will Fixing Drainage Fix My Cracks?

It depends what's already happened. Good drainage stops the cause from getting worse, and in early cases with small cracks that come and go with the seasons, that may be all a house needs. But drainage doesn't lift a slab that has already settled. If you're seeing cracks wider than about 1/4 inch, doors sticking in more than one room, or floors that slope, get it evaluated. Fix the water and the movement, in that order of thinking, even if the work happens at the same time.

A Ten-Minute Walk After the Next Storm

1. Walk the whole perimeter while the ground is still wet.
2. Note anywhere water stands against the foundation, or mud stays wet the next day.
3. Follow each downspout to where the water actually ends up.
4. Look for soil washed away from the slab edge, or new gaps under it.
5. Check patios and walks for tilt toward the house.
6. Take photos. If you call someone, pictures from during the storm are worth more than a description afterward.

Drainage FAQs

Do I need a French drain?

Not usually as a first step. Most Amarillo drainage problems are solved by grading, gutters and downspouts. French drains make sense when water has nowhere to go on the surface, such as a low lot or a yard that slopes toward the house from a neighbor's.

Can I regrade my own yard?

Small areas, yes: pulling soil away from the slab, filling a low spot, and sloping a bed away from the house. Avoid digging below the slab edge, and call 811 before you dig anywhere. Larger regrading usually needs equipment and a contractor.

Does drainage work need a permit in Amarillo?

Generally not for routine regrading or gutters on your own lot, but rules change with the scope of work. Our permit guide covers what the city looks at.