Taking on a new septic design project is a bid deal.
We are grateful you found us.


For over 50 years the McNair family has been designing septic systems in Washington State. In 1972, Scott McNair began working for the Clark County Health Department. He left that position a few years later to begin his own on-site septic design company. Scott continued designing systems for the next 30 years.

In 2005, Scott’s son, Cory began working with him. Cory graduated from Northern Arizona University. After several years managing a restaurant, then a bank he was ready for a change. Working with family was a great privilege and one that was not taken for granted. They were able to enjoy several great years working together before Scott lost his battle with cancer.

In 2015, Andrew Winslow joined the team. Andrew graduated from Whitworth University. In 2019, he was licensed by the state of Washington as an OSS Designer. He is continuing to learn about this evolving industry and develop the knowledge to effectively analyze every aspect of the septic design, installation, and maintenance processes.

 In February of 2021, our team grew with the addition of Alan Salazar. Alan graduated from California Polytechnic University Pomona with a BS in Civil Engineering and in 2014 completed his EIT certification. Amid the unique challenges of 2020, Alan, and his wife (2019 newlyweds) made the decision to transition north to be closer to family in the greater Vancouver area. Alan brings 5+ years of construction management, civil engineering, and plumbing design experience to the team and looks forward to growing his skill set and experience in the septic design industry.

Having two licensed designers on staff to review each project has further allowed McNair Septic Design to uniquely design creative and cost-effective designs throughout Southwest Washington. We believe that they are the only company in Southwest Washington with two licensed designers on staff. So no matter which one of them you speak with, you will be working with a professional. 



  1. Integrity

We will tell you why we are doing what we are doing and share our knowledge with you. Complete honesty is always our goal. If you are not satisfied, let us know and we’ll do our best to correct the problem.

  1. Quality

We are sure you get the quality thing a lot. It is not just the quality of the design, but the quality of the entire experience. Even the smallest projects are held at a high standard of service for us.

  1. Communication

Once we get started we will provide you with a timeline for your project as well as keep you updated if we run into any speed bumps along the way.

  1. Design with you in mind

Every system and situation is different. We promise to look at the details of how your system will be used, and offer our best and most cost effective recommendations to you.

  1. Flexibility

We are not set in our ways and we are happy to adapt to the needs of our clients under the county and state regulations.