FAQs • Contra Costa County, CA • CivicEngage

How do I determine the 25-year 24-hour storm depth?

Find your project location on the Mean Seasonal Isohyet Map that can be found at the Hydrology Standards link (below) and determine the mean seasonal rainfall for your site. Then, use the 25-year Precipitation Duration-Frequency-Depth Curve found at the same link. Find 24-hours (1-day) on the x-axis, go up parallel to the y-axis on the graph to the mean seasonal rainfall for your site. Go horizontal parallel to the x-axis to the y-axis to read off the rainfall depth for the 25-year 24-hour storm.

Hydrology Standards

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PW - How do I, How can I, etc.

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1. How do I obtain GIS information?: For Public Works GIS information, email Wiley Osborn. For Countywide GIS information, email Shashi Ganjam.

2. How are Area of Benefit (AOB) fees determined?: AOB fees are determined based upon the relationship between the total estimated cost to construct road improvement projects on the AOB project list and development potential projections within the AOB boundary.

3. How do I become a vendor?: All purchases for Contra Costa County must be processed by Contra Costa County Purchasing. Email Purchasing or call (925) 957-2499.

4. How do I calculate the Flood Control flow data point? Do I need to know the post development design flows for my project?: If the watershed is small, you can use the Rational Method to calculate the design flow rate. If the area is large or you need hydrographs for designing a detention basin, the Flood Control District can calculate the hydrographs for you. You need to request a HYDRO6 submittal package. There is a fee for the District to calculate the flows for you. Contact the Hydrology Section at the number below and they can e-mail the HYDRO6 instructions and submittal package to you. You may also purchase the submittal package at the front counter of the Public Works Department office (255 Glacier Drive, Martinez, CA 94553).

5. How do I contact an inspector?: If you cannot contact the inspector listed on your permit, you may call the Design/Construction Division at (925) 313-2320.

6. How do I determine the 25-year 24-hour storm depth?

Hydrology Standards

7. How do I find out how much my Area of Benefit (AOB) fees will be for my project?: AOB fees are calculated during the plan check phase of your project. If you would like an AOB fee estimate earlier, you may contact the AOB Program Manager at the Contra Costa County Public Works Department at (925) 313-2000 or email Public Works.

8. How do I get a vesting tentative map for my development project?

Please submit a development plan application to the Community Development Division of the Department of Conservation and Development.

For more information review the Your Project and the Public Works Department document

9. How do I get an encroachment permit?

Please submit an encroachment permit application form to our County Permit Center.

Application & Permit Center
30 Muir Road, Martinez, CA 94553
(925) 674-7200

Visit the Permit Portal for Encroachment Permits information

10. How do I get permission for my contractor and I to temporarily use land owned by the County or Flood Control District?: Please contact Jessica Dillingham, Principle Real Property Agent, at (925) 957-2453 or email the Public Works Department.

11. How do I obtain a title report on my property?: To obtain a title report, you must contact a private title company.

12. How do I report hazardous material spills or dumping?: To report potentially hazardous materials which have been dumped or spilled, contact County Health Services Department - Hazardous Materials Division at (925) 655-3200 or email HazMat. Visit their website for more information.

13. How do I report debris in creeks?: Call the Contra Costa Clean Water Program hotline at 1(800)No-Dumping or report online.

14. How do I report debris on private property or a vacant lot?: If the debris is located on property within a city, contact that city. If the debris is located on private property within the unincorporated area, call the Building Inspection Department at (925) 655-2704 or Building Code Hotline at (925) 655-2737 or visit the Building Inspection webpage for more information.

15. How do I report the lack of garbage services?: Garbage service is mandatory for all occupied residences located within the unincorporated areas (county code chapter 418-6), unless an exemption has been granted by the Health Officer. To make a report please call the County Health Services Department-Environmental Health Division at (925) 608-5500 or email them or file a complaint online. For more information visit the Environmental Health website.

16. How do I report unresolved garbage/recycling collection company complaints?: If you are unable to resolve a service complaint with your garbage/recycling collection company, you can contact the Department of Conservation and Development at (925) 655-2700 and you will be referred to the appropriate governmental agency in your area. For more information visit the Conservation and Development website.

17. How do I record a final map?

Please submit the information indicated on the Final Maps document to our Engineering Services Division at:

Contra Costa County
Public Works Department
255 Glacier Drive
Martinez, CA 94553

If you have questions email Public Works or call (925) 313-2000.

18. How do I transfer title to my child or another person?: Contact the County Assessor's Office at (925) 313-7500.

19. How will I know which number is the streetlight pole number?: The pole number can be 1-10 digits. The numbers are on plastic stickers, about 2-3 inches, with black numerals on a white background.

20. How do I report a train that appears to be stuck and blocking a railroad crossing for an extended period of time?

Blocked crossings occur when stopped trains impede the flow of motor vehicle or pedestrian traffic at railroad tracks for extended periods of time. Blocked crossings pose potential safety risks, specifically in locations where trains routinely hinder roadway and pedestrian movement for extended periods. In these cases, frustrated drivers seeking to avoid extended delays may attempt to clear the crossing before a train arrives, and pedestrians may be tempted to crawl between stopped railcars. Further, blocked crossings can have detrimental effects on quality of life, making people late for work, school, and appointments and possibly contributing to roadway congestion. Currently, there are approximately 130,000 public highway/rail grade crossings in the United States.

If you are experiencing an blocked crossing for an extended period visit the Federal Railroad Administration website to report it.