Soil series profile
Keswick soil series
Keswick is a somewhat poorly drained soil with a silt loam surface, mapped on 1,023,767 acres in 75 counties across 2 states. Hydrologic group D.
- Drainage class
- Somewhat poorly drained 82% of mapped acres
- Hydrologic group
- D 79% of mapped acres
- Typical topsoil pH
- 5.9 moderately acidic · range 5.7–5.9
- Mapped area
- 1.0M acres in 75 counties, 2 states
Typical Keswick profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–7 in (Ap) | Silt loam | 5.7 | 22% | 26% | 2.4% |
| 7–20 in (2Bt) | Clay | 5.5 | 44% | 25% | 1% |
| 20–79 in (2Btg) | Clay loam | 6.7 | 39% | 23% | 0.3% |

What this means
What Keswick soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Keswick soils is moderately acidic: pH 5.9 (most land between 5.7 and 5.9). Many vegetables grow well here, and some gardens benefit from a little lime. Test before adding any.
Loamy topsoil (loam, silt loam and similar) covers 100% of mapped Keswick acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is silt loam (61% of mapped Keswick acres).
82% of mapped Keswick acres is somewhat poorly to very poorly drained, so soil stays soggy for long spells after rain and in wet seasons. Raised beds, plants that tolerate wet feet, and not working the soil while wet all help.
For lawns and yards
On 100% of mapped acres, rain soaks in slowly (hydrologic groups C and D, including dual groups that are D until drained). Expect runoff and puddles after heavy rain: core-aerate compacted lawns and keep ground sloping away from foundations.
A seasonal high water table comes within 18 inches of the surface on 38% of mapped acres, often in spring. Basements, sump pumps and lawns in low spots feel it first.
For a septic system
For conventional septic absorption fields, NRCS rates 100% of the acres in mapped Keswick soils very limited, 0% somewhat limited and 0% not limited.
Where the soil is very limited (slow permeability, a high water table, flooding, shallow bedrock or steep slopes), alternative systems such as mound or sand-filter designs are common and cost more.
Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.
Where Keswick soil is found
Mapped acres
Keswick is mapped in Missouri and Iowa. The 60 counties with the most Keswick acres:
| County | Acres | Share of county land |
|---|---|---|
| Callaway County, MO | 92,705 | 17.3% |
| Boone County, MO | 86,798 | 19.9% |
| Macon County, MO | 75,986 | 14.8% |
| Lincoln County, MO | 73,576 | 18.4% |
| Randolph County, MO | 72,956 | 23.7% |
| Pike County, MO | 49,265 | 11.5% |
| Warren County, MO | 48,537 | 17.7% |
| Monroe County, MO | 47,874 | 11.5% |
| Lewis County, MO | 42,550 | 13.3% |
| Montgomery County, MO | 37,183 | 10.8% |
| Audrain County, MO | 32,025 | 7.2% |
| Shelby County, MO | 27,726 | 8.7% |
| Putnam County, MO | 27,685 | 8.4% |
| Clark County, MO | 26,912 | 8.3% |
| Sullivan County, MO | 22,997 | 5.5% |
| Davis County, IA | 19,241 | 6.0% |
| Lee County, IA | 16,882 | 5.1% |
| Decatur County, IA | 16,751 | 5.0% |
| Howard County, MO | 14,705 | 5.0% |
| Wapello County, IA | 13,717 | 5.0% |
| Van Buren County, IA | 12,516 | 4.1% |
| St. Charles County, MO | 11,416 | 3.2% |
| Knox County, MO | 11,363 | 3.5% |
| Appanoose County, IA | 11,075 | 3.5% |
| Henry County, IA | 10,577 | 3.8% |
| Keokuk County, IA | 10,059 | 2.7% |
| Monroe County, IA | 9,249 | 3.3% |
| Adair County, MO | 8,079 | 2.2% |
| Linn County, MO | 7,508 | 1.9% |
| Schuyler County, MO | 7,357 | 3.7% |
| Lucas County, IA | 6,857 | 2.5% |
| Iowa County, IA | 6,275 | 1.7% |
| Washington County, IA | 5,670 | 1.6% |
| Jefferson County, IA | 5,391 | 1.9% |
| Chariton County, MO | 5,147 | 1.1% |
| Mahaska County, IA | 4,834 | 1.3% |
| Worth County, MO | 3,985 | 2.4% |
| Marion County, MO | 3,684 | 1.3% |
| Des Moines County, IA | 3,633 | 1.4% |
| Scotland County, MO | 3,096 | 1.1% |
| Clarke County, IA | 3,034 | 1.1% |
| Johnson County, IA | 2,740 | 0.7% |
| Marion County, IA | 2,664 | 0.8% |
| Mercer County, MO | 2,081 | 0.7% |
| Tama County, IA | 1,979 | 0.4% |
| Louisa County, IA | 1,952 | 0.8% |
| Ralls County, MO | 1,861 | 0.6% |
| Poweshiek County, IA | 1,718 | 0.5% |
| Cedar County, IA | 1,521 | 0.4% |
| Ringgold County, IA | 1,374 | 0.4% |
| Madison County, IA | 1,118 | 0.3% |
| Johnson County, MO | 1,009 | 0.2% |
| Warren County, IA | 972 | 0.3% |
| Jasper County, IA | 840 | 0.2% |
| Union County, IA | 666 | 0.2% |
| Jones County, IA | 588 | 0.2% |
| Linn County, IA | 560 | 0.1% |
| Muscatine County, IA | 504 | 0.2% |
| Benton County, IA | 492 | 0.1% |
| Scott County, IA | 484 | 0.2% |
Septic absorption fields
NRCS rating, share of Keswick acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 0.0% |
| Very limited | 100.0% |
Drainage, water table and flooding
Share of Keswick acres
- Depth to seasonal high water table
- About 2.0 feet (24 in) (median where reported); within 18 inches on 38% of acres.
- Flooding
- Not mapped as flooding on most acres.
- Slope
- Typically 7–16% (median 10%).
- Topsoil organic matter
- Median 1.5%.
Drainage class
Show as a table
| Category | Share of acres |
|---|---|
| Excessively drained | 0.0% |
| Somewhat excessively drained | 0.0% |
| Well drained | 0.0% |
| Moderately well drained | 17.7% |
| Somewhat poorly drained | 82.3% |
| Poorly drained | 0.0% |
| Very poorly drained | 0.0% |
Hydrologic soil group
Show as a table
| Category | Share of acres |
|---|---|
| A: fast infiltration (mostly sandy or gravelly) | 0.0% |
| B: moderate infiltration | 0.0% |
| C: slow infiltration | 0.0% |
| D: very slow infiltration (clayey, shallow or wet) | 78.9% |
| A/D: D as is, A if drained | 0.0% |
| B/D: D as is, B if drained | 0.0% |
| C/D: D as is, C if drained | 21.1% |
Sources & data dates
- Source
- USDA NRCS Soil Survey Geographic Database (SSURGO), queried through Soil Data Access. Public domain.
- Data date
- SSURGO as published on November 3, 2026 (most recent survey area update October 26, 2026). NRCS refreshes SSURGO each October.
- Scope
- All map unit components named Keswick (component kind "Series") in SSURGO: 1,023,767 acres.
- Method
- Shares are by mapped acres of Keswick components. The profile comes from the single largest Keswick component. Full methodology.