The short answer
In a long dry spell, yes, water near your foundation, gently and evenly. The goal isn’t wet soil; it’s soil that stays about as moist under the edge of the slab as it is under the middle. The ASCE Geo-Institute’s homeowner guide calls uniform soil moisture next to and under a foundation the single best thing you can do to limit shrink-swell movement.
Too much water is its own problem. ASCE Texas, which publishes the guidelines Texas engineers use for foundation evaluation, says owners should keep near uniform soil moisture on all sides of the foundation and advises caution against excessive watering in the same section.
Why watering helps on this clay
Collin County’s main soil, Houston black clay, has high shrink-swell potential. In summer the clay along the edge of a slab dries first, shrinks and lets the edge settle while the middle stays put. Watering the edge slows that.
North Texas summers make it matter. The National Weather Service counted 55 days of 100-degree heat at DFW in 2023, and in 2026 DFW went 67 days without measurable rain. North Dakota State University Extension notes that rewetting dried soil often brings a house back toward alignment, so doors may realign when soil is rewetted.
How to water a foundation
- Lay a soaker hose around the house, about 18 inches out from the foundation, as the Geo-Institute suggests. Not against the slab, and not under a bed you also water by sprinkler.
- Favor the hot sides. The Geo-Institute advises more water on the drier sides, which in North Texas usually means the south and west walls.
- Water when the soil is drying, not on a fixed schedule all year. Push a screwdriver into the soil near the hose; if it goes in easily and comes out damp, skip a day.
- Run it slowly. A soaker hose should seep, not spray. If water runs off toward the street or puddles at the slab, cut back.
- Stop after real rain and restart only when the soil dries again.
- Keep a log of when you water and how the doors and cracks behave. It’s useful at any inspection.
A plain timer on the spigot helps, but check it after every heavy rain so it isn’t running into saturated ground.
What each city allows
Each city sets its own watering schedule, and they differ more than you’d expect. What their published rules say:
| City | Sprinklers | Hand-held or soaker hose | Daytime limit |
|---|---|---|---|
| Plano | twice per week at most, April through October | Foundations and landscaping up to two hours any day | See the city’s current notice |
| McKinney | On your trash day and three days later, as needed | Beds and trees may be watered more often with hand-held hoses, soaker hoses or drip zones | No watering 10 a.m. to 6 p.m. from April 1 to October 31 |
| Frisco | once per week, on your trash day, with a second day in summer | Hand-held, soaker and drip when needed, no more than 2 hours per day | No watering 10 a.m. to 6 p.m. from April 1 to October 31 |
| Allen | Check the city’s water conservation page | We couldn’t find a published rule on foundation watering | Check the city’s current rules |
Plano is the only one of the four whose guidelines we found naming foundations directly. McKinney’s rule speaks of trees, flowers and gardens; a soaker hose along the foundation bed falls naturally under it, but if you’re unsure, ask the city’s water conservation office. In any city, the Geo-Institute’s advice holds: know and obey your city's watering bans during droughts, because stricter drought stages can replace these rules.
When not to water
- After a good rain, or when the soil near the house is already damp.
- Near a known or suspected leak. A plumbing leak under the slab is already feeding water to the clay. Fix the leak first.
- On the side that’s heaving. If the middle or one side of the house is rising, adding water there makes it worse. An inspection should come before more watering.
- Into a bed that ponds. Fix the grading or edging first; the drainage page explains how.
The Geo-Institute’s guide also warns against watering for lush plantings: water just enough to keep plantings alive and growing, not until the ground is saturated.
Automatic foundation watering systems
Some contractors install perimeter watering systems that drip water along the slab on a timer. The Foundation Performance Association treats them as maintenance, which should not be considered a repair, and lists their risks: over-watering can cause adverse movement, and dramatic foundation settlements could occur if a system the soil has come to depend on stops working. If you install one, plan to maintain it for as long as you own the house.
Signs you’re getting it wrong
- Too little: gaps opening between the soil and the slab edge, doors near outside walls binding in late summer, stair-step cracks widening.
- Too much: soggy soil days after watering, water standing against the slab, doors in the middle of the house binding, cracks appearing after a wet spell rather than a dry one.
If the cracks keep growing whatever you do, the warning signs page explains what to look for, and a contractor’s inspection will show whether the house has moved.
Want a contractor to look at it? Call to schedule an inspection.