FAQs
General information
- Information is available at the Environmental Health office. You can call Environmental Health at 925-608-5500 to request an information packet be mailed to you. The office can direct you to the district inspector who will provide assistance throughout the process.
Septic system process (each step requires an application)
- Site and soil evaluation.
- Percolation testing.
- Design of onsite wastewater treatment system.
- Construction permit.
- Monitoring program (if an alternative system).
Well construction process
- Contract with a licensed well driller who is approved to work in Contra Costa County.
- Submit a permit application, that must be signed by a licensed driller and include a plot plan drawn to scale.
What tests do I need to have done on my water well?
Existing well: Existing wells require a bacteriological test performed by a California State Certified laboratory. The Environmental Health office has a list of certified laboratories.
New well: A new well that has been permitted and approved by the Environmental Health Division requires two tests:
- A four-hour pump test to determine if the well can produce at least 3.0 gallons per minute sustained production rate.
- A water bacteriological test to determine if any Coliform bacteria are present.
Does a well driller need any special licenses?
A well driller must possess a current C-57 (well drilling) license and be approved to work in Contra Costa County.
How can I tell if my septic system is not performing adequately?
There are several signs to watch for:
- Water drains slowly down the sink drain
- A complete backup into the house
- Septic drain field may show a damp or ponding of liquid at the surface
- A sewage odor may be detected
How near can my well be to my septic system?
The minimum distance from the well to the septic tank and leach field is 100 feet.
What is a soil profile?
- A soil profile is a hole that is excavated to expose the soil layers in a proposed drain field area.
- A soil profile starts by excavating a trench with a backhoe. The trench is usually 7 feet deep to expose the soil layers. Benching is required at 3.5' for safety.
- Evaluation of the excavated soil layers will indicate whether the soil is suitable for a septic system drain field.
- Direct observation of the pit can show evidence of shallow groundwater levels or other issues that could limit the soil's suitability.
How often should I have my septic system pumped?
It is recommended to have the septic system pumped every three to five years, or when the sludge accumulates to within 12 to 18 inches from the bottom of the outlet sanitary tee.
What size leach field should I have for my septic system?
The size of the drain field is calculated from the information obtained from the soil profile, percolation test and the number of bedrooms proposed for the single-family dwelling.
What is a perc test?
A percolation test, or perc test, is a test used to determine soil permeability (the rate by which water can be absorbed into the soil).
What types of certifications/licenses are required for septic system consultants?
Septic system consultants, or "qualified professionals," who do site and soils evaluations must be a civil engineer, environmental health specialist, geologist, professional soil scientist or engineering geologist. They must be licensed, registered or certified by the State of California.
What types of certifications/licenses are required for septic system contractors?
- Septic system contractors and registered installers must have a State of California Contractor's license (Type A, B, C-36, or C-42) to construct, enlarge, alter, repair, improve, or replace an individual septic system or its components.
- Registered installers in Contra Costa County must have current worker's compensation insurance for any employees working on system construction.
- Contractors are not allowed to design septic systems. Only California-licensed civil engineers and registered environmental health specialists are allowed to design or change the design of a septic system.
How do I convert from a septic system to a public sewer?
- Contact the public sewer agency.
- Contact your local public sewer agency to determine if your property can connect to a public sewer. For information on connecting to public sewers, visit the website for your area:
- Apply for a septic tank abandonment permit.
- Apply for the permit at the Environmental Health Office located at 2120 Diamond Boulevard, Suite 100, Concord, California.
- Proper abandonment of septic tanks is important because an unused septic tank can be a safety hazard. Old steel tanks, thin, rusting steel tanks, and rotting homemade wood tank covers are at risk of collapse. Falling into a septic tank can lead to asphyxiation from methane gas or burial.
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