Most of Vancouver is on sewer, but septic systems are common on rural parcels around Battle Ground, Brush Prairie, La Center, Ridgefield and the hills above Camas and Washougal. HomeGuide's national septic page shows $3,500 to $8,500 to install a conventional system.
We did not set the dollar figures on this page: they are national ranges from HomeGuide. In Clark County, wet-season clay, trees, slope, groundwater and haul distance are what push a real job up or down. Figures checked October 2026.
How much does a new septic system cost?
HomeGuide's septic page gives three bands for a new septic system: conventional at $3,500 to $8,500 installed, alternative at $4,000 to $15,000 and engineered at $15,000 to $50,000 or more. The tank, at 1,000 gallons, costs $1,000 to $1,500 of that. Wet clay soils and high winter water tables in the north county often call for something other than a basic gravity system.
What does replacing a drain field cost?
A drain field replacement runs $3,000 to $15,000, averaging $7,900 nationally, on HomeGuide's drain field page. Fixing or rejuvenating an existing field is $1,000 to $5,000; a new tank with a new field, $4,500 to $20,000.
How do I know my drain field is failing?
Warning signs of a failing drain field include soggy ground or bright green grass over the field in a dry spell, sewage smell, slow drains, gurgling and backups. In a wet winter, standing water over the field is a clue too. Start with pumping and an inspection; HomeGuide lists pumping at $300 to $700.
Do I need a perc test or soil evaluation before a septic system?
Yes. A septic system in Washington is designed from a soil and site evaluation, and the design goes to the local health department for a permit. Expect the perc test on a Clark County lot to fall in HomeGuide's $600 to $2,000 range. We dig the test holes the designer asks for.
How much does a mound septic system cost?
A mound system costs $25,000 to $50,000 or more on HomeGuide's septic page. Mounds raise the drain field above native soil where the ground is too wet or too shallow, which is common on Clark County clay. Pressure distribution and aerobic systems, $20,000 to $40,000 or more for an aerobic unit, are other options.
What does it cost to replace a crushed or broken septic line?
HomeGuide lists a new sewer or septic line at $40 to $180 a foot, around $1,600 to $7,200, with a camera check first at $125 to $500. Lines crushed by vehicles or broken by roots and settling are common on older rural lots.
How big is the hole for a 1,000-gallon tank, and how do I find the lid?
The hole needs room on every side so the tank can be set level and backfilled, and the depth comes from the tank maker and the approved design. HomeGuide has no price for that hole. To find a buried lid, check the county health department's records for your property, then probe where the as-built drawing shows.
Can I connect to city sewer instead of replacing my septic?
Sometimes, if a public sewer is close and the sewer district or city allows it. HomeGuide prices a septic-to-sewer conversion at $3,000 to $15,000, with hookup fees of $1,000 to $15,000. The old tank then has to be pumped and decommissioned under the health department's rules.
Who issues septic permits in Clark County?
In Clark County, septic permits come from Clark County Public Health, which reviews designs and inspects installations. In Portland and other Oregon areas, onsite permits are handled under Oregon's rules by the county or state office for that area. We dig for the designer and installer on the approved plan; we do not design systems.
Tell us about your project and we will come look at the ground, then send the scope and the price in writing. Call or text (360) 276-9112.