Septic System Engineering Design

Tim Johnston, Registered Civil Engineer  with Acorn Onsite, Inc.

Tim Johnston, P. E. is the Civil Engineer on staff that has a lifetime of experience dealing with septic systems. Tim has worked through residential septic system projects and large scale commercial facility onsite wastewater treatment system projects. Acorn Onsite, Inc. has the long term solution as the focus of our efforts. We are experienced with and have positive relationships with the regulators, both at the County Environmental Health Agency level and at the California Regional Water Quality Control Board. We are compentent working through all the appropriate wastewater permitting processes. We can perform all tasks in house or we are happy to work with other consultants, professionals, architects, engineers, contractors, installers, surveyors, etc. as appropriate.

Field Studies

Soil investigation including: soil profiles, percolation testing, topographic surveying, mapping, groundwater determination, wet weather testing, soil observation and analysis 

OWTS Design

Onsite Wastewater Treatment System (septic system) engineering designs. We utilyze a cost effective, appropriate septic system design for your parcel. Either if it is for residential, commercial, winery, industrial use.

Septic Permitting

We are experienced working through OWTS permitting process of the various county Enviornmental Health Departments. 

System Evaluation

If you have an existing septic system that is giving you some trouble, give us a call and we can asses the options. Maybe it's a simple fix or maybe something more complicated. We are always interested in the long term solution to problems.


Acorn Onsite, Inc. staff is committed to providing long term onsite wastewater treatment system solutions. We care for the envionrnment and we care for the customer's needs.

Onsite Wastewater Treatment Systems

We prepare an appropriate septic system design for the site. We work on residential dwellings, commercial facilities, institutional facilities, wineries, industrial warehouse, and anywhere in between. We work in Alameda County, Stanislaus County, Santa Clara County, San Mateo County, Marin County, Solano County, Napa County, Yolo County, Contra Costa County, Sacramento County, and everywhere throughout Central California. We are experienced working through any county or State permitting procesess.  

Give us a call today to speak about your project (925) 447-5200 or 1-800-832-7711

Some of the Types of systems we design include:

Conventional Gravity (Standard System)

When site and soil conditions are favorable for a simple, gravity flow leach field we find this type appropriate. As conditions, such as soil type and compact spaces, get "worse" or less favorable, more complicated system types are used.

Shallow Trench Pressure Distribution

On sites where shallow soils are found often a shallow trench pressure distribution system is appropriate. These system utilyze a pump or siphon to use the shallow soils to treat the effluent.

Drip Dispersal

In shallow soils or where a pretreatment unit is necessary, drip dispersal is sometimes an appropriate technique.

At-grade Bed Dispersal

In shallow soils, underlaid by shallow rock, hard soils, high groundwater levels, etc. an at-grade bed dispersal system may be appropriate for the site.

Pretreatment Units

If conditions or permit requirments necessitate further treatment than the depth of soil allows at the site, a pretreatment unit can be used. 

The type of septic system that is designed is based on the site and soil conditions encountered in soil testing, topography surveying, site layout, and other site developement activities. Give us a call to discuss your site and see how we can help you on your next development.

(925) 447-5200 or 1-800-832-7711

Soil Testing and Observation Techniques 

We are competent working through any soil testing and observation for septic systems. Some of the techniques we use include the following:

Initial Surface Conditions Observation

A visual walk through of the site surface conditions provides usefull information. Depending upon the slope, surface soil types, vegetation, and other features indicate some tell tale signs for an OWTS design.

Soil Profile

A soil profile is used to classify the soil in the potential leach field area. Often a backhoe is used to dig about 10 to 12 feet deep and classify the soil characteristics. Depth to a limiting condition such as groundwater are also observed.

Percolation Testing

Often called perc tests, percolation testing is used to determine a rate water percolated into the soil. The percolation rate is then correlated to the long term aceptance rate of the soil.

Wet Weather Testing

In some soil types it is appropriate to determine how the soil behaves in the wet season of the year. Groundwater monitoring and other testing is sometimes used at this stage.

Location Experience and Published Reference Review

Acorn Onsite, Inc.
(925) 447 - 5200
2288 Buena Vista Avenue
Livermore, CA

Complete Septic Systems
CSLB# 499418

Call us for your wastewater needs.

Serving Central California

Counties of: Alameda, Contra Costa, Santa Clara, San Juaquin, Stanislaus, Tuolumne, Calaveras, Alpine, Amador, El Dorado, Sacramento, Solano, Yolo, Napa

2288 Buena Vista Avenue
Livermore, CA 94550

Phone: (925) 447-5200
Fax: (925) 447-0919

Acorn Onsite, Inc. Is an engineering and construction firm based out of 2288 Buena Vista Avenue, Livermore, CA 

94550. CSLB # 499418, serving Alameda County, Contra Costa County, Santa Clara County, San Joaquin County, 

and surrounding areas in Central California.