Nassau County, New York
The most common soil here is Riverhead, on about 10% of the land: a sandy loam, gritty and crumbly. Montauk and Udipsamments come next.
About 25% of the land drains well, and 5% stays wet for long stretches; groundwater comes within two feet of the surface under 7% of it.
USDA rates 34% of the land very limited for a standard septic drain field, and 10% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 5% of the land floods occasionally or more.
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 soils you're most likely standing on
The biggest named soils in Nassau County, New York, each drawn five feet deep from its official USDA description, in its recorded colors.
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 Well drained and the dominant hydrologic group is C (slow infiltration, moderate runoff). 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 Nassau County, New York. Search your address to find the exact soil composition, drainage, and series details at your specific location.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Urban land-Riverhead complex, 0 to 3 percent slopes | 36K | Not rated | Not rated | ||
| Water | 27K | Not rated | Not rated | ||
| Urban land | 19K | Not rated | Not rated | ||
| Urban land-Hempstead complex | 18K | Not rated | Not rated | ||
| Montauk loam, 3 to 8 percent slopes | 13K | Well drained | C | Somewhat limited | Very limited |
| Urban land-Montauk complex, 3 to 8 percent slopes | 8K | D | Not limited | Not limited | |
| Ipswich mucky peat, 0 to 2 percent slopes, very frequently flooded | 7K | Very poorly drained | A/D | Very limited | Very limited |
| Urban land-Sudbury complex | 7K | Not rated | Not rated | ||
| Urban land-Udipsamments, wet substratum complex | 6K | Not rated | Not rated | ||
| Montauk loam, 8 to 15 percent slopes | 6K | Well drained | C | Somewhat limited | Very limited |
| Riverhead sandy loam, 3 to 8 percent slopes | 6K | Well drained | A | Not limited | Very limited |
| Udipsamments, wet substratum | 5K | Moderately well drained | A | Not limited | Very limited |
| Urban land-Riverhead complex, 3 to 8 percent slopes | 5K | Not rated | Not rated | ||
| Riverhead sandy loam, 8 to 15 percent slopes | 4K | Well drained | A | Somewhat limited | Very limited |
| Enfield silt loam, 0 to 3 percent slopes | 4K | Well drained | B | Not limited | Very limited |
| Plymouth-Riverhead complex, 15 to 35 percent slopes | 3K | Excessively drained | A | Very limited | Very limited |
| Hempstead silt loam | 3K | Well drained | B | Not limited | Very limited |
| Enfield silt loam, 3 to 8 percent slopes | 3K | Well drained | B | Not limited | Very limited |
| Montauk loam, 0 to 3 percent slopes | 3K | Well drained | C | Somewhat limited | Very limited |
| Riverhead sandy loam, 0 to 3 percent slopes | 2K | Well drained | A | Not limited | Very 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.
What This Means
Building & Foundations
Most soils are generally favorable for residential construction. Standard foundations are usually viable, though site-specific evaluation is always recommended.
Septic Systems
About 34% of soils have significant septic limitations, while others are more suitable. A perc test is essential — conditions vary across the area.
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.