Local project context
Soil and percolation testing for Colton septic projects
Colton spans developed valley floor near the Santa Ana River and long-established transportation and industrial corridors.
For the limited parcels considering onsite disposal, floodplain position, past grading, and utility availability are more useful screening questions than a citywide soil assumption.
Septic soil testing is useful only when the field locations represent the proposed disposal area. Surface appearance, a regional soil map, or a result from a nearby parcel cannot establish the absorption rate or soil conditions for this site.
