Liquid Waste FAQ
When is a sewage disposal permit required?
A sewage disposal permit is required:

  • To install a new sewage disposal system
  • To repair, modify or expand an existing sewage disposal system
  • To replace or destroy any of its components such as the septic tank
For sewer line repairs, modifications, or installations only, please contact the County Building Division.
What information is required to obtain a permit?
In order to receive a permit, a complete application package must be submitted for the proposed on-site sewage disposal system that complies to Solano County Code requirements, see On-Site Sewage Disposal Standards On-site Sewage Disposal System (Solano County Code CH 6.4). A complete application plan includes:

  • Completed application form
  • Application fees 
  • Two copies of the site evaluation report prepared by a registered consultant
    • On-site review describing surface features of the lot and the area of the on-site sewage disposal system.
    • Soil profile data. This is a characterization of the soil?s physical features and identification of the depth of any limiting features, including groundwater indicators, fractured rock, or bedrock in the proposed initial and replacement sewage disposal field areas.
    • Hydrometer test and bulk density data (performed using USDA test methods), or percolation test data, depending on the most limiting soil type observed in the leaching layers of the proposed septic system based on the soil profile.
  • Two copies of a plot plan, including the design and calculations for the on-site sewage disposal system prepared by a Professional Civil Engineer, Certified Engineering Geologist, or Registered Environmental Health Specialist. The plot plan and design must demonstrate compliance to code requirements given the site evaluation data.
  • Floor plan
Upon submission the applicant will need to schedule an appointment with the staff of the Environmental Health Services Division to verify the information submitted. After review of the application package and a site inspection verifies compliance to code requirements, the staff will issue a septic permit. Building projects require that the Sewage Disposal Permit be issued concurrently with the Building Permit.
I would like to locate my sewage disposal system. Does the County maintain these records?
Yes. Solano County does maintain records of sewage disposal system installations and repairs performed under permit issued by this Division. These records may include an "as-built" drawing of the septic system which may indicate the approximate size and location of the system. If this information is not available or found incomplete, you may contact a licensed septic contractor or qualified consultant to assist you in finding the size, location, and layout of your system.
Can a sewage disposal system be installed any time of the year?
No. Sewage disposal systems shall not be installed between November 15 and April 15 without prior approval from this Division. To install a system during this period, you must contact this Division to request a site evaluation. An Environmental Health Specialist from this Division must inspect a test trench to verify soil conditions are unsaturated and appropriate for the installation of a disposal field.
How do I know if a site is suitable for the installation of an on-site sewage disposal system?
Installation of a septic system cannot be guaranteed unless there is a currently valid Sewage Disposal Permit issued by the Environmental Health Services Division for the development proposed on the lot. If there is not a currently valid permit, you may need to consult with a registered consultant to evaluate the lot to determine the likelihood that such a permit can be issued. Key factors that play a role in determining if a Sewage Disposal Permit can be issued include:
  • Physical characteristics of the soil
  • Soil absorption capability
  • Depth of soil
  • Depth of limiting condition(s), including high groundwater indicators, fractured rock, bedrock, impermeable soils
  • Disposal area available for initial and replacement systems
  • Maintenance of setback requirements
  • Physical features of the lot in the area and immediately adjacent to the sewage disposal system
  • Maximum projected sewage flows from the development (for residential development this is 150 gallons per day for each bedroom proposed).
Who is a registered consultant?
A registered consultant performs soil evaluations. Registered consultants are Registered Environmental Health Specialists, Professional Engineer-Civil, Registered Geologist, or Certified Professional Soil Scientist. While all these professions can perform the soil evaluation, only a Registered Environmental Health Specialist, Certified Engineering Geologist, or Professional Engineer-Civil can complete the on-site sewage disposal system design.
Who is qualified to construct a sewage disposal system?
Septic systems can be constructed by a licensed contractor with a current Class "A", "C-42", or "C-36" license. The owner/builder may also construct the septic system provided they have obtained the County construction guidelines and are familiar the requirements.
Does Solano County inspect sewage disposal systems for lender verification of proper system operation?
Solano County no longer conducts these inspections. Please contact a licensed septic contractor or registered consultant to perform these services.
How frequently should a septic tank be pumped?
Typically septic tanks need to be pumped every 3-5 years, depending on the tank size, the amount of solids entering the tank, and the habits of the users. The tank should be pumped if the scum and sludge layer exceed 49% of the volume of the first compartment of the tank or if the sludge on the bottom of the tank is within 12 inches of the bottom of the sanitary tee.

What are my requirements if I have an alternative system?
Alternative systems shall be operated, maintained and monitored pursuant to Solano County Code Chapter 6.4 including obtaining an annual operating permit. The operation and maintenance  of the systems includes on an annual the submission of a report detailing performance and maintenance annually. Additionally, every three years the maintenance  and performance evaluation shall be conducted by manufacturer approved provider who maybe a licensed contractor or register consulant.