Septic companies in Portland, OR

What the ground in Portland is like

The USDA soil survey rates mapped ground in Portland for septic drain-field suitability across roughly 133 square miles. About 100% of the rated ground is classed "Very limited", meaning the soil has one or more features unfavorable for a conventional drain field, and the limits generally cannot be overcome without major soil reclamation, special design or expensive installation.

In Portland, 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 92% of the rated ground here.

The limiting features the survey records most often here:

• Slow water movement91.8%
• Seepage, bottom layer67.5%
• Depth to saturated zone36.9%
• Slope27.7%

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 · 113 map units · 133.48 sq mi · read 2026-08-30