septic systems in oregon: What every landowner should know before building

By Forged Built- Oregon’s Trusted Construction Partner

If you are planning to build a home, shop, or outbuilding on land without city sewer success, there's one thing you need to get right from the start: your septic system.

Whether you are building in Oregon, installing a septic system is a critical (and sometimes overlooked) step in the construction process. At Forged Built, we help landowners across Oregon navigate the permitting, design, and installation process the right way- before construction even begins.

Here is what every Oregon landowner needs to know about septic systems before breaking ground.

WHAT IS A SEPTIC SYSTEM, AND WHY DO YOU NEED ONE?

A septic system is an on-site wastewater treatment system used in areas not connected to a municipal sewer. It collects wastewater from your home- think toilets, sinks, showers, laundry, and treats it underground before safely returning it to the soil.

A septic system typically includes:

• A septic tank (to separate solids from liquids)

• A drain field (where liquids effluent is absorbed into the soil)

• Optional components like pumps, filters, or sand filters for challenging soil

If your property does not have sewer success and most rural lots in Oregon dont, You will need a septic system installed and proved before you can get a building permit.

YOU CAN’T BUILD WITHOUT SEPTIC APPROVAL

Before you can even apply for a building permit in Oregon, you must show that your land can legally and safely support a septic system. That’s where site evaluation comes in.

Step (1): Site Evaluation (Perc Test)

• Conducted by a licensed Onsite Wastewater Specialist or DEQ agent

• Involves digging test pits to evaluate soil type, depth, and drainage

• Determines if the land can absorb and treat wastewater safely

Step (2): Septic System Permit

• Once your soil passes, you apply for a permit to design and install the system

• Some systems require standard tanks; others need engineering designs if soil is rocky, wet, or shallow

Forged Built Tip: We always recommend doing the septic site evaluation before buying or building. It is often a deal-breaker if the land won’t perk- or only support a limited system

OREGON TERRAIN= OREGON SEPTIC CHALLENGES

Oregon’s geography in incredibly diverse. What works in Bend may not work in McMinnville. That’s why local knowledge is so important.

Common Septic Challenges in Oregon:

• Clay soils in the Willamette Valley that drain slowly

• Steep grades in mountain regions affecting tank placement

• High water tables near rivers, lakes, and the coast

• Shallow bedrock

In some cases, alternative systems like sand filters, pressure distribution, or mound systems are required. These can be more costly, but they make building possible on land many others overlook.

WHO HANDLES SEPTIC INSTALLATION?

Only licensed contractors certified by Oregon’s DEQ can legally install septic systems. Forged Built:

• Coordinates site evaluations

• Plans tank and drainfield placement around your build

• Ensures the system won’t interfere with your shop, driveway or future plans

We often build with septic in mind, adjusting driveway grading, building orientation, and landscaping to optimize space and function.

WHAT YOU CAN DO TO PREPARE

Here is how to make sure you septic planning does not slow down your build:

Before you buy land:

• Ask if the lot has a DEQ approval septic site

• If not, require a site evaluation contingency in your offer

• Consider the space needed for primary + backup drainfield

Before you build:

• Get your site evaluated and permitted

• Design your build around septic zones

• Avoid driving or building over your drainfield

Forged Built Tip: Even if your land has an old septic system, it may not meet current code. Always verify with DEQ before assuming it can be reused.

Partner with Forged Built- We know Oregon Dirt.

We dont just build structures, we help you build smarter from the ground up. That incudes understanding your soil, your setbacks, and your long-term septic system needs. Whether you are building a shop, home, or multi-use outbuilding, we make sure your project starts on solid ground- literally.

Lets talk Forged Built can guide you through the septic approval process and build your dream from the dirt up. Free Consultations!!!

Call or Text (971) 486-6587

Levi@forgedbuilt.com

Skyler@forgedbuilt.com

JJ@forgedbuilt.com