Professional septic system installation and underground utility services

Prepping sites for over 25 years

do you have a project we can help with?

specialists in excavation and septic systems

We offer professional and experienced excavation services in SW Washington.

Septic Systems

Septic Systems must be done right the first time. We will properly install your septic system to ensure years of trouble free service and promote ease of maintenance.
We are certified and competent to take on the most challenging sites.

Septic to Sewer

We offer septic to sewer conversions for clients in Clark & Cowlitz county.
If you’re interested in converting from a septic system to city sewer in your area, contact us.

Under ground

Here in the Northwest, having good and reliable underground utilities is critical.
Seppanen Construction will look to accomplish that for you, whether it be through gas trenching, installing a water line, or any of our many underground services.

Brush Mowing

We now offer site prep including brush mowing, excavator mounted flail mower for road right of way, property clearing and fire break clearing.

Let us help you get your site prepped and ready for the build process.

Explore Recent Work

Take a peek at some recent projects, do any of these look like your project? 

Our Core Values

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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. 

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Site prep, excavation, clearing, septic system installation, septic conversions, and more

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