Kansas / Anderson County
Score 53 · elevated · #4 of 105 in KS
Crawl space moisture in Anderson County, KS
89% of Anderson County's soil falls in hydrologic group D or a dual D group: clays and high water tables that shed water slowly. Where a seasonal water table is reported — 76% of acres — it averages 1.5 ft below grade, shallow enough to reach a typical crawl-space footing.
- 1Water table 1.5 ft
- 2Wet soils 34%
- 3Moisture score 53
- 4EPA radon zone 2
Reading the Anderson County soil survey
The score of 53 combines four parts, each from the USDA survey: wet drainage classes contribute 39 points of 100 on their own scale, group D soils 88.8, a shallow water table 58.1, and flooding 8.7; the weights are on the methodology page. The dominant hydrologic group is D (85% of acres): very slow infiltration, high runoff (clays, high water table).
A water table under two feet is the single most important number here. A crawl-space floor is usually 18 to 36 inches below the joists and often below outside grade, so in a wet season groundwater can stand at or above the crawl-space floor across much of Anderson County. Venting cannot fix that; it needs drainage — a perimeter drain to daylight or a sump — before any liner goes down.
Anderson County against the rest of Kansas
Anderson County ranks 4 of 105 Kansas counties, 40 points above the state median of 13. That puts it in the wettest quarter of the state. Statewide, 8% of mapped soil is in the wet drainage classes; here it is 34%, half again the state figure or more. After moderately well drained, the next most common class is somewhat poorly drained at 31%.
Flooding. 3.9% of acres with a flooding class are rated frequent; 7.6% of acres with a flooding class are rated occasional; 1.2% of acres with a flooding class are rated rare. Flood-prone soils are a minority here, concentrated along streams; the score mostly reflects what happens between floods.
What it means for a crawl space here
In an elevated county the soil supplies more moisture than average, but a vented crawl space can work if the ground is covered: the code lets vent area drop from 1 sq ft per 150 to 1 per 1500 with a Class I vapor retarder on the ground, which is an admission of how much moisture comes from below. Grading, gutters and a ground cover usually decide whether a crawl space here stays dry before any decision about sealing it.
Radon. EPA radon zone 2. The zone is a county-level prediction; EPA says elevated levels occur in every zone and every home should be tested.
Near Anderson County by score
Sources: USDA NRCS SSURGO via Soil Data Access (muaggatt: drclassdcd, hydgrpdcd, flodfreqdcd, pondfreqprs, wtdepannmin), acreage-weighted (survey area KS003; drainage covers 100% of 373,708 mapped acres); EPA Map of Radon Zones, county table (June 2024 JSON); IRC R408.3 Unvented crawl space, as adopted in S.C. Code Regs. 8-1221 (LII). Checked 2026-10-23.