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specialists in excavation and septic systems
We offer professional and experienced excavation services in SW Washington.
Explore Recent Work
Take a peek at some recent projects, do any of these look like your project?
Septic to Sewer Conversion Project making a conversion possible are you ready to change from septic to sewer? Let us get you hooked up properly. Get a free quote Woodland, Washington Conversion
septic system installation septic system install do you need a septic system installed on your lot? Get a free quote Amboy, Washington Septic System Install Septic system installation is our specialty! We
Underground Project do you have a project we can help with? Get a free quote Kalama, Washington Once the project's foundation was completed, we came in and installed rain drains, dug for power
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FAQ’s
Browse some of our frequently asked questions, or contact us if you’d like a direct answer to your question.
Test pits (commonly called perc holes) are needed to determine what type of soils are at your property and to determine the depth to the restrictive layer. We do not provide the soils analysis aka "perc testing", but we can refer you to several good
In order to get a bid from us, you'll need to have a septic system design. If you're looking for good septic system designer, please visit the links below, or contact us for referrals. Clark County (PDF). Cowlitz County.
Does your septic tank need to be pumped? Seppanen Construction, LLC does not offer septic tank pumping. We're happy to offer a recommendation for this task. Visit the county of your residence below for more information. Clark County (PDF). Cowlitz County.