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Cap-and-Fill Septic System Installation — Lane County, Oregon

A complete on-site wastewater solution engineered for challenging soil conditions

When a property's soil profile won't support a conventional drainfield, the solution requires more than just equipment — it requires a contractor who understands the engineering, the permitting, and the long-term performance of an elevated system. 3-A Construction delivered exactly that on this Lane County project.

The work began where every successful septic system begins: in the ground. Our crew excavated test holes to evaluate soil characteristics and confirm the site called for a cap-and-fill design — an elevated drainfield built up with imported sand fill to provide the vertical separation DEQ requires between effluent and the restrictive soil layer below. From there, we installed a septic pump tank engineered to pressure-dose the elevated field, ensuring even distribution across the entire disposal area.

The heart of the system is 450 linear feet of EZflow gravelless drainfield, laid out with precision trench spacing, bedding, and cover to meet Oregon DEQ specifications and Lane County Land Management requirements. Every component — tank placement, pump sizing, force main, distribution, and final grading — was installed to spec and inspected for compliance. The result is a code-compliant system built to perform reliably for decades on a site that couldn't accommodate a standard gravity drainfield.

Why it matters: Cap-and-fill systems are one of the more technically demanding septic designs in Oregon. They require proper fill material, correct compaction, accurate pump calculations, and strict adherence to DEQ rule 340-071. A system installed incorrectly can fail inspection, fail prematurely, or both — and the cost of redoing one is far higher than the cost of doing it right the first time.

3-A Construction, LLC — CCB #167959 — Licensed Oregon general contractor specializing in manufactured home placement, site development, and septic installation across Lane, Linn, Tillamook, and surrounding counties.