It's important to know who you're working with.

Acorn Onsite, Inc. is an established Civil Engineering and Construction firm that specializes in septic systems. We enjoy working with our customers on the most difficult septic system projects as well as the more straightforward sites throughout Central California. We have a particular expertise in the field that justifies our involvement in your project. 

Our Credentials

Reach out to discuss more of your septic system needs

About Acorn Onsite, Inc.

Serving the OWTS needs of all California Counties

Acorn Onsite, Inc. provides complete solutions for onsite wastewater. Members of our staff have been in the wastewater industry since 1980. Acorn Onsite, Inc. was incorporated in 2006.


Acorn Onsite, Inc.'s unique for the industry approach of providing all septic system services under one
company will benefit you, the customer, by having the skills, knowledge, understanding, and tools for the complete project, start to finish. We also enjoy working with others in the industry with each of us performing our part.


Our staff enjoys working through your project and providing you with a long-term wastewater solution. We provide you with sound, knowledgeable advice, giving you the confidence you deserve.


We work on behalf of our customer to navigate the regulations appropriately.   


Acorn's staff enjoys working with all types of clients throughout the septic system development process. Including property owners, engineers, architects, contractors (both specialty and general), real estate agents, property owner's representatives, property purchasers, first time septic system owners, and everyone in between.


Give us a call today at 925-447-5200 to discuss how we can put our expertise to the test on your next project or septic system process.

A slopping hillside in the feasibility determination stage of septic system engineering design.

A slopping hillside in the feasibility determination stage of septic system engineering design.

Our Staff

Tim Johnston, PE

Tim Johnston, PE evaluating the surface condition for septic system engineering purposes.

Civil engineer Tim Johnston has a lifetime of experience working at all levels of septic system projects.

Kevin Johnston

Kevin Johnston with Acorn Onsite, Inc. observing a soil profile for septic system feasibility.

Kevin is following in his father's footsteps serving California's need for appropriate septic system expertise.