Onsite Wastewater Treatment System Program

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Also known as: Septic Systems

Septic Code changes effective July 1, 2016

Why were there changes?

Assembly Bill 885 was approved by the California State Assembly in September 2000. FAQ of AB 885.

Because of AB 885, the State Water Resources Control Board then adopted the Water Quality Control Policy for Siting, Design, Operation, and Maintenance of Onsite Wastewater Treatment Systems (OWTS) Policy, effective in May 2013.  Fact Sheet for the OWTS Policy.

The State OWTS Policy requires local agencies to adopt either Tier 1 standards (general, broad, and sometimes very restrictive requirements); or develop a Tier 2 Local Agency Management Program (LAMP), that allows alternative methods from Tier 1 requirements in order to achieve the same purpose of protecting water quality and public health but with local flexibility.

Yolo County Environmental Health Division developed a Tier 2 LAMP which consists of two parts, an updated local ordinance a new manual. Yolo County Board of Supervisors adopted the Ordinance, which adopted by reference the manual. These documents can be accessed by the following links.

What is an Onsite Wastewater Treatment System / Septic System?


Septic systems are needed to dispose of human sewage/wastewater on a site where connection to a community sewer system is not available. Septic systems then treat this sewage

What's Important to Know?
checkmarkDesign: A properly planned Septic System is important, and it all starts with a Site and Soils Evaluation.
checkmarkInstallation: Yolo County's Septic Manual provides important installation information.
checkmarkMaintenance: The Septic System
Maintenance Handout
provides important information for septic system owners.

Please Remember: Septic Systems will not function properly forever...BUT a properly designed, installed, and maintained septic system can function for a very long time!


EPA website: www.epa.gov/septic
EPA info: Do Your Part - Get Septic Smart: Poster
EPA info: Top 10 Ways to Be a Good Septic Owner: Flyer
EPA info:What To Do After the Flood


Standard/Gravity Septic System vs. Alternative Septic System

The most basic system, the standard/gravity-fed system, consists of a septic tank, one or more distribution boxes, distribution perforated lines and enough available, native soil, capable of treating the liquid waste.

An alternative system requires engineering considerations beyond a standard system, to address limiting site conditions (high water table, impervious soil, rock layer, etc.) and/or proper effluent treatment.

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Environmental Health Division



 Contact Us

Environmental Health
292 West Beamer Street
Woodland, CA 95695

8am-12pm & 1pm-4pm

Phone: (530) 666-8646
Fax: (530) 669-1448

Email: Environmental Health


What is the Role of Environmental Health?

Improper human sewage disposal can cause ground water contamination, pollute streams and rivers, create breeding of nuisance insects, create noxious odors, and contribute to the spread of disease.

Environmental Health issues permits for the installation, modification, repair, and abandonment of domestic sewage disposal systems in order to prevent these problems.

Environmental Health also investigates septic or sewage complaints as reported by the public. .

Permit Information

A permit to construct is required from Environmental Health whenever a septic tank is replaced or abandoned, or if leach lines are replaced or repaired.

Permits can be obtained at Yolo County Environmental Health.

A septic design starts with a Site Evaluation and Soils Profile.

Septic Pumper Trucks

Vehicles that pump, haul and dump sewage in Yolo County must have a valid permit from Yolo County Environmental Health. Vehicles are permitted and inspected on an annual basis.

For Applications, visit Form and Applications for Onsite Wastewater Treatment System Program to register your vehicle. 

For operational requirements, click here.

For a quarterly service record report template, click here.

For spill kit requirements, click here.



Frequently Asked Questions

How Far Away Does My New Pool Need To Be From My Septic System?
Required setbacks from a septic tank and a leach field are listed on our Septic System Minimum Setback handout. A pool deck also needs to meet the pool setback; nothing should be built over a leach field because it would hinder the necessary aerobic treatment of the system.

Whom Can I Contact To Work On My Septic System?

Contractors with either a General Engineering (A), or Specialty Plumbing (C-36), or Sanitation System (C-42) License are qualified to repair or install septic systems under the regulations of the contractor’s licensing board. At times, a General Building (Class B) License can be approved for some jobs. Property owner may also perform some septic installations and repairs in Yolo County. There is an active list of Septic System Contractors doing business in Yolo County; however, this list may not be all-inclusive and Environmental Health Division does not endorse contractors.

What Can I Do To Properly Maintain The Septic System?

  • Use minimal amounts of water to avoid overloading the leach field.
  • Don’t dispose of pesticides, solvents, waste oil, anti-freeze or other hazardous chemical into the septic system. These chemicals could kill the important bacteria in the tank that is necessary for a properly functioning system. Also, improper disposal of these hazardous items can result in fines and expensive clean-up measures.
  • Limit the use of a garbage disposal and limit the amount of grease, food scraps, garbage, and non-biodegradable items going into the septic system.
  • Know the location of your septic tank and leach field, and the leach replacement/repair area. Keep copies of all septic permits and record all septic services, such as septic tank pumpings. Your septic tank should be routinely pumped by a Yolo County licensed septage pumper/hauler.

Click the Link for a copy of EPA's A Homeowner's Guide to Septic Systems and Yolo County's Septic System Maintenance Handout for more important tips.

Whom Should I Contact for Emergency Repair?

If your system is failing, please call a septic system contractor immediately. The non-inclusive list of septic contractors is available by clicking here.

If sewage has backed up to the house or has surfaced on the ground, avoid allowing people or animals near the area. Avoid using plumbing fixtures until the repair has been made. For useful tips on how to clean up a sewage spill, please click here.

How Do I Abandon A Septic Tank?

Septic tanks are abandoned when septic systems are no longer needed, such as a home connecting to a public sewer system, or when the tank has failed.  There are 2 methods of abandonment:  removal of tank, and burial. 

For complete requirements, please go to our Septic Abandonment webpage .