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Land Use Program FAQ


What do I need to install a septic system or water well?

  1. Information is available at the Environmental Health office or you can call Environmental Health at 925-692-2500 to request for an information packet to be mailed.
  2. Reception can direct you to the district inspector who will provide assistance throughout the process.
  3. Septic System Process (each step requires an application)
    1. Site and soil evaluation
    2. Percolation Testing
    3. Design of Onsite Wastewater Treatment System
    4. Construction Permit
    5. Monitoring Program (if an alternative system)
  4. Well Construction Process:
    1. Contract with a licensed well driller, who is approved to work in Contra Costa County. The permit application 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
Bacteriological test performed by a California State Certified laboratory. A list of laboratories can be obtained in our office.

New Well
A new well that has been permitted and approved by the Environmental Health Division requires: (a) four hour pump test to determine if the well can produce at least 3.0 gallons per minute sustained production rate; and (b) a water bacteriological test to determine if any Coliform bacteria are present.

Does a well driller need any special licenses?

A well driller must posses 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?

Some signs to watch for to determine if a septic system is not performing adequately include: (a) water drains slowly down the sink drain; (b) a complete backup into the house; and (c) septic drainfield may show a damp or ponding of liquid at the surface and 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 leachfield 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 drainfield area. Through the soil profile, evaluation of the soil layers will indicate the suitability of the soil for a septic system drainfield and direct observation of the pit show evidence of shallow groundwater levels or other limiting layer.

How is a soil profile done?

A soil profile starts by excavating a trench with a backhoe usually 7 feet in depth to expose the soil layers. Benching is required at 3.5' for safety.

How often should I have my septic system pumped?

It is recommended to have the septic system pumped every 3 to 5 years. Or, when the sludge accumulates to within 12 to 18-inches from the bottom of the outlet sanitary tee.

What size leachfield should I have for my septic system?

The size of the drainfield 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 perc test or percolation test is a test that is used to determine the permeability or the rate in which water can be absorbed into the soil.

What types of certifications/licenses are required for Septic System Consultants?

The septic system consultants or "Registered Professional" must be a State of California Registered Environmental Health Specialist, geologist, Civil or Soils Engineer.

What types of certifications/licenses are required for Septic System Contractors?

Septic System Contractors or "Registered Installers" must possess 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 system, or many of the components of an individual system. A registered installer doing business in Contra Costa County must have current verification of worker's compensation insurance on file with the Department if any employees work on system construction.

How do I convert from a septic system to public sewer?

Step I: Contact public sewer agency:
The applicant should contact the local public sewer agencies to determine if the property is can connect to sanitary sewer. For information regarding connecting to public sewer, click on the links below:


Step II: Apply for septic tank abandonment permit
Apply for a septic tank destruction permit at the Environmental Health Office located at 2120 Diamond Boulevard, Suite 200, Concord, California. A septic tank that is no longer in use may pose a safety hazard. Old steel tanks, thin, rusting steel or rotting homemade wood tank covers are at risk of collapse. Falling into a septic tank may lead to asphyxiation from methane gases and in cases of collapse; there is risk of becoming buried.