Septic companies in The Dalles, OR

What the ground in The Dalles is like

The USDA soil survey rates mapped ground in The Dalles for septic drain-field suitability across roughly 6.7 square miles. About 98% of the rated ground is classed "Very limited", the survey records severe restrictions for a conventional drain field across most of that ground.

In The Dalles, the leading limit is slope: the ground falls steeply enough that a level trench line is hard to hold. A drain field has to sit across the grade without concentrating flow downhill; on steeper parcels that layout gets tighter. The survey flags that limit on about 76% of the rated ground here.

The limiting features the survey records most often here:

• Slope76.2%
• Depth to bedrock71.4%
• Slow water movement33.6%
• Seepage, bottom layer23.6%

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 · 98.4% Very limited · Slope · 29 map units · 6.69 sq mi · read 2026-08-30