Soil survey area

Kitsap County Area, Washington

Survey Area WA635• Washington
The short version

The most common soil here is Alderwood, on about 17% of the land: a gravelly sandy loam, gritty and crumbly. Harstine and Shelton come next.

About 21% of the land drains well, and 7% stays wet for long stretches; groundwater comes within two feet of the surface under 37% of it.

USDA rates 92% of the land very limited for a standard septic drain field, and 82% very limited for homes with basements. That means extra cost or special design, not that it can't be done.

Worth knowing: bedrock lies within 40 inches under 4% of it.

Soils change over short distances, so look up an address below for the soil at that exact spot and the reasons behind each rating.

The ground underfoot

The soils you're most likely standing on

The biggest named soils in Kitsap County Area, Washington, each drawn five feet deep from its official USDA description, in its recorded colors.

Alderwood
17% of the area
Gravelly sandy loam topsoil · moderately well drained
Gritty and crumbly. Drains fast and warms early in spring.
Inceptisols
Harstine
12% of the area
Gravelly ashy sandy loam topsoil · moderately well drained
Gritty and crumbly. Drains fast and warms early in spring.
Inceptisols
Shelton
10% of the area
Very gravelly sandy loam topsoil · moderately well drained
Gritty and crumbly. Drains fast and warms early in spring.
Andisols
Poulsbo
7% of the area
Very gravelly sandy loam topsoil · moderately well drained
Gritty and crumbly. Drains fast and warms early in spring.
Inceptisols
Ragnar
6% of the area
Fine sandy loam topsoil · well drained
Gritty and crumbly. Drains fast and warms early in spring.
Inceptisols
Indianola
6% of the area
Loamy sand topsoil · somewhat excessively drained
Gritty and loose. Water runs straight through it.
Entisols

Dots mark gravel; white flecks mark lime. Shares are by acres across the survey area, and each mapped patch usually mixes several of these soils.

The biggest mapped areas

The dominant drainage class is Moderately well drained and the dominant hydrologic group is B (moderate infiltration). The most common soil order is Inceptisols — young soils with minimal horizon development but more than Entisols. This report summarizes the major soil map units across the survey area to help you understand what to expect when buying, building, or gardening in Kitsap County Area, Washington. Search your address to find the exact soil composition, drainage, and series details at your specific location.

Soil Map UnitAcresDrainageHydro GroupDwellingsSeptic
Alderwood gravelly sandy loam, 0 to 8 percent slopes 18K Moderately well drainedBVery limitedVery limited
Alderwood gravelly sandy loam, 8 to 15 percent slopes 18K Moderately well drainedBVery limitedVery limited
Harstine gravelly ashy sandy loam, 0 to 6 percent slopes 14K Moderately well drainedCNot limitedSomewhat limited
Dystric Xerorthents, 45 to 70 percent slopes 13K Moderately well drainedAVery limitedVery limited
Kapowsin gravelly ashy loam, 0 to 6 percent slopes 11K Moderately well drainedBVery limitedVery limited
Harstine gravelly ashy sandy loam, 6 to 15 percent slopes 11K Moderately well drainedCVery limitedVery limited
Poulsbo gravelly sandy loam, 0 to 6 percent slopes 9K Moderately well drainedB/DVery limitedVery limited
Alderwood gravelly sandy loam, 15 to 30 percent slopes 8K Moderately well drainedBVery limitedVery limited
Indianola-Kitsap complex, 45 to 70 percent slopes 8K Somewhat excessively drainedAVery limitedVery limited
Norma fine sandy loam 8K Poorly drainedB/DVery limitedVery limited
Harstine gravelly ashy sandy loam, 15 to 30 percent slopes 7K Moderately well drainedCVery limitedVery limited
Kapowsin gravelly ashy loam, 6 to 15 percent slopes 6K Moderately well drainedBVery limitedVery limited
Shelton extremely gravelly sandy loam, 0 to 6 percent slopes 6K Moderately well drainedDVery limitedVery limited
McKenna gravelly loam 5K Poorly drainedDVery limitedVery limited
Kilchis very gravelly sandy loam, 30 to 70 percent slopes 5K Well drainedDVery limitedVery limited
Ragnar fine sandy loam, 0 to 6 percent slopes 5K Well drainedANot limitedVery limited
Shelton extremely gravelly sandy loam, 6 to 15 percent slopes 5K Moderately well drainedDVery limitedVery limited
Indianola loamy sand, 0 to 5 percent slopes 4K Somewhat excessively drainedANot limitedVery limited
Shelton very gravelly sandy loam, 0 to 6 percent slopes 4K Moderately well drainedA/DVery limitedVery limited
Poulsbo-Ragnar complex, 6 to 15 percent slopes 4K Moderately well drainedB/DVery limitedVery limited

Soil Orders in This Area

The USDA classifies every soil into one of 12 soil orders. Here are the dominant orders found in this survey area.

Inceptisols
Young but developing soils found in mountains and river terraces. Variable properties — check drainage and bedrock depth.
Andisols
Volcanic ash soils — light, porous, and fertile. Excellent drainage, but low density can complicate foundations.
Entisols
Young soils with little development — found on floodplains, dunes, and steep slopes. Properties vary widely by setting.
Spodosols
Acidic forest soils with a leached layer. Common under conifers. Often have drainage issues from a compacted subsoil layer.

What This Means

Building & Foundations

About 82% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, poor drainage in some areas. A geotechnical assessment is recommended before building.

Septic Systems

About 92% of soils are rated "very limited" for septic absorption fields. Despite good drainage overall, limitations may stem from shallow bedrock, steep slopes, or seasonal conditions. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.

Gardening & Agriculture

Well-drained soils on sloped terrain — good for most plants but watch for erosion. Terracing, contour planting, and mulching help retain moisture and topsoil. Drip irrigation is more effective than sprinklers on slopes.

Look Up a Specific Address

📍