Onsite Wastewater Basic Information

Here's a little information to educate the knowledgeable homeowner on the basics of onsite wastewater systems (septic systems). As you have questions or if you would like further information, please call us to speak with an engineer about your questions or concerns. 

925-447-5200

Some basic information on a septic system

A pressure distribution leach field under construction in Byron, CA. Homeowners DIY septic install.

What is a Septic System anyways?

A septic system is an onsite wastewater treatment system that is used to treat and disperse of the sewage generated on the site.


In essence the typical process of a septic system is as follows: All of the sewage from the building flows into a septic tank. Some treatment occurs within the septic tank then the cleaner water (refereed to as effluent) flows to a leach field. The effluent then disperses into the ground where final treatment and entrance back into the environment occurs. 

Are they all the same?

Every septic system is unique. A septic system is based upon site specific conditions, information, and site uses. A septic system-or Onsite Wastewater Treatment System-consists of a septic tank and disposal field. The specifics of each component must be specified for the site specific conditions. 

What do I need to do when I have a septic system?

Proper use and maintenance are an important part of a septic system's longevity. Some typical maintenance tasks include: pumping the septic tank, respond to apparent surface conditions, and maintain components as specified by the engineer.

What is a septic tank?

The septic tank provides time for primary treatment to occur. A typical residential septic tank is about 1500 gallons divided into two compartment. The solids are settled to the bottom and fats/oils/grease float on the surface. The middle layer provides a relatively clear zone that flows through the baffle into the second compartment. The effluent flows from the second compartment out to the leach field.

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What is a leach field?

All leach fields are different, but the purpose of all leach fields is to distribute the effluent to allow dispersal into the soil. Leach fields distribute the effluent into the soil where the soil treats the effluent and allows for water to enter back into the environment.

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What is a leach field sized for?

Leach fields are sized based on the soil absorption characteristics, topography, and other site specific conditions. Call us today (925) 447-5200 to discuss the specifics of your site and speak with an engineer to discuss a plan of action for your onsite wastewater needs. We don't want you to waste your money and we will give you options for the most appropriate long term solution for the site's wastewater needs. 

Septic design

A little more info

A recently installed leach field in Clayton, CA. Notice the new house and recent leach field.

House and Septic System

Notice the septic system is below ground. You should not have any smell from a septic system. If there is smell, something is not right and should be evaluated. Give us call to discuss 925-447-5200

A septic tank being set in the excavation in Castro Valley, CA. Concrete septic tank used here.

Septic tank

The septic tank is one component of the septic system. The tank's purpose is to provide time for the constituents of the sewage to settle. The effluent (pretreated sewage) then exits the septic tank to a leach field.

Septic tank drain field under construction in Byron, California.

Leach field under construction

A leach field is the system that disperses effluent into the ground. All leach fields are slightly different and each leach field is specific to the project site. 

Septic System Care

Additional Information

Even the best septic system needs to be maintained. Please call Acorn Onsite, Inc. to speak to an engineer about proper care. Our staff can be reached at 925-447-5200


Check out our blog for further information regarding septic systems. We periodically post new information, so check back in. 


Septic Tank Pumping:

The usage and sizing of the septic tank will dictate the pumping interval. Generally a residential septic tank should be pumped about every 3 to 5 years.


To Have Optimal Performance Follow These Guidelines:

  • Do not drive cars, trucks, or heavy machinery over a leach field.
  • Planting invasive trees or shrubs near a leach field is better to avoid.
  • Dispose of chemicals properly, do not pour heavy amounts of cleaners down the drain.
  • Wash the laundry over the course of the week rather than all at once.
  • Flush only toilet paper and human waste down the toilet. Don't use the toilet as a trash can.
  • Monitor your septic system, both the septic tank and the leach field general vicinity. A typical residential septic tank should be pumped about every five years.

Outlet Filters:

If installed, outlet filters should be cleaned annually, simply hose off the built up solids. If an outlet filter is not installed please ask about the benefits the next time the tank is pumped. If the filter has been damaged or questions arise please call Acorn Onsite, Inc at 925-447-5200.

A possible drip dispersal leach field location in Carmel California. Steep slope under the redwoods.

A possible drip dispersal leach field location in Carmel California. Steep slope under the redwoods.

All images displayed on this website were taken by staff of Acorn Onsite, Inc. at project sites of Acorn Onsite, Inc.