Septic companies in San Mateo, CA

What the ground in San Mateo is like

The USDA soil survey rates mapped ground in San Mateo for septic drain-field suitability across roughly 12 square miles. About 75% of the rated ground is classed "Not limited", the survey records few restrictions for a conventional drain field across most of that ground.

In San Mateo, 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 24% of the rated ground here.

The limiting features the survey records most often here:

• Slope23.8%
• Depth to bedrock6.1%
• Slow water movement5.3%

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 · 75.4% Not limited · Slope · 14 map units · 12.12 sq mi · read 2026-08-30