Basement in St. George, UT

Connect with local trade pros serving St. George and the rest of Washington County.

Basements in St. George

Basements are less common in St. George than in northern Utah, but many homes have partial basements, crawlspaces or rooms built into a hillside. In this area, soils and radon are the main concerns below grade.

Radon

Utah's Department of Environmental Quality says about 1 in 3 Utah homes tested, and 1 in 2 in some areas, have radon above 4 picocuries per liter, and that the average in tested Utah homes was 5.3. Radon can only be detected by testing. Test before you finish a basement or below-grade room; a radon system is easier to install before walls go up. Most systems use a fan and pipe to draw soil gas from under the slab and vent it above the roof.

Collapsible soils

The Utah Geological Survey says collapsible soils are common in the St. George–Hurricane area, chiefly young debris-flow sediments on alluvial fans. They're strong when dry but can settle up to 10 percent of the deposit's thickness when wetted for the first time. For a basement, that means water is the threat: irrigation, a leaking line or a downspout dumping water beside the foundation can trigger settlement. Keep irrigation away from the foundation, and send downspout water well away from the house.

Other soil conditions

The Utah Geological Survey's hazard maps for the area also cover expansive soil and rock, which swells when wet; gypsiferous soil and rock, which can dissolve; caliche; and shallow groundwater. A basement wall built against expansive clay can be pushed by swelling soil. Ask the contractor whether they've seen a geotechnical report for your lot. If you're building or adding below-grade space, ask whether one should be done.

Water

Rain here is infrequent but can be intense, and summer storms flood quickly. Window wells need drains and covers. Ask how the contractor will handle drainage at the foundation, and whether a sump is needed for your site.

Finishing

Ask how they'll insulate the walls, how they'll keep moisture out of the framing and what egress windows they'll use for bedrooms. In a hot climate, a cool basement can collect condensation on summer days; ask about dehumidification if the space feels damp.

Before you hire

Ask for a written scope that separates drainage, radon work and finishing. Ask who pulls permits and schedules inspections, and get references from basement jobs.

Local facts behind this page

Utah's Department of Environmental Quality says about 1 in 3 Utah homes tested, and 1 in 2 in some areas, have radon above 4 picocuries per liter, and that the average in tested Utah homes was 5.3; radon can only be detected by testing. Source: Utah Department of Environmental Quality, January is National Radon Action Month
The Utah Geological Survey says collapsible soils are common in the St. George–Hurricane area, chiefly young debris-flow sediments on alluvial fans; strong and stiff when dry, they can settle up to 10 percent of the deposit's thickness when wetted for the first time, damaging structures. Source: Utah Geological Survey, Special Study 127, Collapsible Soil map plate
The Utah Geological Survey's hazard maps for the St. George–Hurricane area cover expansive soil and rock, collapsible soil, gypsiferous soil and rock, caliche, shallow bedrock, wind-blown sand, breccia pipes and paleokarst, soil piping and erosion, and shallow groundwater. The survey describes the area as one of Utah's fastest-growing regions for more than two decades, and notes that as land well suited for development grows scarce, building has moved into less favorable areas. Source: Utah Geological Survey, Geologic-Hazard and Adverse-Construction-Condition Maps for the St. George–Hurricane Area

Sources checked 2026-10-26. Codes, rebates and standards change; the contractor you hire and your local building department have the final word on what applies to your property.

Before you hire in Washington County

Get Basement Pros doesn't check contractors' credentials for you, so do it yourself before you sign anything: look the contractor up with DOPL's license lookup, and for plumbing or electrical work check that trade's license too. The Utah Division of Professional Licensing (DOPL) lookup is free: Utah Division of Professional Licensing (DOPL).

Get the scope, price and timeline in writing before work starts.
Ask who pulls any required permit, and whether an inspection is part of the job.
Ask for proof of insurance and for references from recent local jobs, and call them.