Septic Systems work on a jobsite in Washington

Septic Systems in Washington

Septic Systems contractors in Washington

Conventional, chamber, mound and aerobic systems installed to the approved design, with the health department inspection before backfill.

View contractors

Project guide

Hiring septic systems contractors in Washington

Septic contractors install and replace the tank, distribution box and drain field that treat wastewater on properties without sewer. Nothing goes in the ground until a soil evaluation or percolation test has been done and the county or state health department has approved a system design; the installer builds to that design and the inspector looks at the open trenches before they are covered. Conventional gravel-and-pipe drain fields are the least expensive where soil drains well, but heavy clay, high water tables and small lots push jobs toward chambers, sand mounds, drip dispersal or an aerobic treatment unit, each with a different price and maintenance schedule. Most states license septic installers separately from general contractors, and many require a pumping and inspection record at property sale.

GradeLine lists 233 septic systems contractors that serve Washington.Compare their work and equipment, then confirm availability and service area before requesting a quote.

Listed businesses are based in WOODINVILLE, WALLA WALLA, SELAH, SEATTLE, SPANAWAY, BREMERTON, though most crews travel well beyond their home city.

What septic systems work costs

A conventional gravity system on well-draining soil typically runs $5,000 to $12,000 installed. Chamber and pressure-dosed systems land in the $8,000 to $18,000 range, and mound or aerobic treatment systems commonly cost $15,000 to $35,000 because of the extra fill, pumps and electrical work. The soil evaluation and design usually add $500 to $2,000 up front.

Ranges are national and approximate; regional labor rates, material prices and site conditions move them in both directions.

Common projects

  • New conventional and chamber systems for new construction and additions
  • Drain field replacement, tank replacement and system upgrades when a field has failed
  • Mound, aerobic and engineered systems for poor soil, high water table or small lots

What affects a quote

  • System type and size, which the design sets by bedroom count and the soil evaluation
  • Depth to seasonal high water table or rock, the amount of fill or sand required, and haul distances
  • Tank material and access, pump and alarm components, and the cost of the design, permit and inspections

Septic Systems FAQ

What does septic systems work cost?

A conventional gravity system on well-draining soil typically runs $5,000 to $12,000 installed. Chamber and pressure-dosed systems land in the $8,000 to $18,000 range, and mound or aerobic treatment systems commonly cost $15,000 to $35,000 because of the extra fill, pumps and electrical work. The soil evaluation and design usually add $500 to $2,000 up front.

What should I share when requesting a septic systems estimate?

Pull together any existing septic permit or as-built drawing, the plot plan showing the well, house and property lines, the bedroom count, and any recent inspection or pumping record.

What can change the cost of septic systems work in Washington?

The main cost items are system type and size, which the design sets by bedroom count and the soil evaluation; depth to seasonal high water table or rock, the amount of fill or sand required, and haul distances; tank material and access, pump and alarm components, and the cost of the design, permit and inspections. A site visit helps the crew see which ones apply.

Do septic systems projects in Washington need permits?

Every state requires a permit for new or replacement septic systems, issued by the county or state health department after a soil evaluation and design review. Setbacks from wells, streams and property lines are fixed by code, and the system must be inspected before the trenches are backfilled.

Directory

Septic Systems contractors serving Washington

233 contractors found

Need a septic systems contractor in your area?

Tell us about the job and add photos. A local pro calls you back. Free, and no spam.

Request services