Septic companies in Portsmouth, NH

What the ground in Portsmouth is like

The USDA soil survey rates mapped ground in Portsmouth for septic drain-field suitability across roughly 16 square miles. About 100% of the rated ground is classed "Very limited", the survey records severe restrictions for a conventional drain field across most of that ground.

In Portsmouth, the leading limit is slow water movement: effluent does not drain through the soil fast enough, so a conventional field can back up or pond when the ground cannot keep pace. The survey flags that limit on about 53% of the rated ground here.

The limiting features the survey records most often here:

• Slow water movement53.1%
• Filtering capacity46.8%
• Seepage, bottom layer46.8%
• Depth to saturated zone36.4%

This is survey data for mapped areas, not a substitute for a site evaluation on your own lot. Conditions on a single parcel can differ from the map.

USDA NRCS SSURGO, ENG Septic Tank Absorption Fields · 100% Very limited · Slow water movement · 38 map units · 15.66 sq mi · read 2026-08-30