Septic Design & Consulting in Cowlitz County

Septic Design & Consulting Services in Cowlitz County

When it comes to septic design in Cowlitz County, you need a partner who understands both the technical requirements and the local permitting process. At McNair Septic Design & Consulting, we handle every step—from soil evaluations and percolation testing to detailed system design and county approval. Our family has been designing septic systems in Washington since the 1970s, and that three-generation expertise means your project is backed by decades of hands-on knowledge.

We provide septic system consulting and design services throughout Cowlitz County, including Longview, Castle Rock, Woodland, Kalama, and surrounding communities. Whether you’re planning a new home, upgrading an existing system, or tackling a challenging property, we create solutions specific to your site—not one-size-fits-all plans. By working with local health departments on your behalf, we simplify the often-complex approval process, saving you time and stress.

Our design process always begins with a careful evaluation of your property’s soils, topography, and future plans. This ensures that the system is not only compliant with Cowlitz County requirements but also designed for long-term reliability and efficiency. We are fully licensed, insured, and independent, which means our recommendations are based solely on what works best for you—not tied to specific manufacturers.

From basic gravity systems to more advanced designs such as pressure distribution, sand filters, and mound systems, we’ve successfully designed septic systems for every type of property. No matter the scope, McNair Septic Design & Consulting is committed to delivering septic solutions that fit your budget, your timeline, and your property.