Grading & Leveling in Amarillo, TX

Before anyone buries pipe in your yard, it is worth asking whether the ground itself is pointed the wrong way. Grading reshapes the soil so water runs away from the house and toward a place it can leave. On a lot of Amarillo properties it is the first fix to try, and sometimes the only one needed.

The code guideline

The International Residential Code, section R401.3, says lots should be graded to drain surface water away from foundation walls, with the grade falling at least 6 inches within the first 10 feet. Where a lot line, wall, or slope makes that impossible, the code calls for drains or swales to carry water away instead, and it asks for hard surfaces within 10 feet of the foundation to slope at least 2 percent away from the building.

Plenty of older yards no longer meet that. Soil settles beside the foundation after construction, beds get built up, sod gets laid on top of sod, and the slope that once ran away from the house ends up running toward it.

Built on flat ground

The NWS describes its Amarillo station, a few miles from downtown, as sitting in a region of rather flat topography about 3,700 feet above sea level, with nearly treeless grasslands sloping downward to the east. Pullman clay loam, the USDA benchmark series common on these plains, occurs on slopes of 0 to 3 percent, and the USDA's typical profile was described on a 0.3 percent slope. On ground like that, nature contributes almost no fall. The slope your yard has is mostly the slope somebody built.

High ground has mattered from the start

Amarillo's founders argued about this almost from the start. The Handbook of Texas recounts that Henry B. Sanborn insisted the original townsite sat on low ground that would flood during rainstorms and set out to move the town out of its mudhole. By 1890 the center of town had shifted about a mile east to Sanborn's higher location. Your house cannot move, but the ground around it can be reshaped to work the same way.

What regrading involves

• Elevations first. We take readings with a level across the yard so the plan is based on numbers, not on how the grass looks.
• Cut and fill. High spots that block flow get cut down, low spots that hold water get filled with soil and compacted in lifts so they do not sink back into a dip.
• Slope at the house. The first ten feet out from the walls get the fall the code describes, or as close as the lot allows.
• Swales. Shallow, broad channels that collect runoff and steer it around the house toward the outlet. Seeded or sodded, they read as part of the lawn.
• A destination. Graded water still has to go somewhere: daylight, a city-approved curb outlet, a catch basin, or a sump.

Canyon edges and the breaks

Not every property in the area is flat. The NWS notes the Canadian River runs north of the city with its bed about 800 feet below the plains in places, and Palo Duro Canyon to the south is about 1,000 feet deep. On lots near a draw, a canyon rim, or the river breaks, the risk flips: runoff concentrates and moves fast enough to cut gullies. There, grading spreads water out instead of funneling it, and swales get rock lining where flow is strongest.

What grading cannot do

Reshaping the surface moves water across the yard, but it does not make slow clay drink faster. If the soil stays soggy after the surface has drained, a French drain may be needed under the regraded area. If the whole lot sits lower than the street, grading points water at the low spot and a pump does the rest.