Flood Facts

Did You Know:

  • CastleOaks2_2Floods happen in all 50 states. Walnut Creek has experienced several flood events during the last 50 years. Much of downtown Walnut Creek flooded during a major storm event in 1958. More recently localized flooding occurred in 2002 and 2005 resulting in damage to homes and private properties.
  • Walnut Creek and its tributaries drain over 146 square miles within central Contra Costa County. The primary flood hazard to residents comes from Walnut Creek through the downtown area, Tice Creek and tributaries to Grayson Creek in northwest Walnut Creek. Localized flooding, however, can occur in any location.
  • Homeowner's insurance does not cover flood damage which can be caused by as little as an inch of water. Properties located within the Special Flood Hazard Area (SFHA) also referred to as the 100-year floodplain have 26% chance of experiencing flood during the life of a 30-year mortgage.
  • If you live in a SFHA, your mortgage lender requires you to have flood insurance. Click here [PDF] for more information.
  • You are eligible to purchase flood insurance as long as your community participates in the National Flood Insurance Program. The City of Walnut Creek participates in the NFIP program and residents are eligible for some discount on the flood insurance rates.
  • It takes 30 days after purchase for a policy to take effect, so it's important to buy insurance before the floodwaters start to rise.
  • All claims and expenses of the NFIP program are funded by insurance premiums, not tax dollars. Read more facts by going to the FloodSmart website.
  • Real-time rain gauge and stream gauge information is available at the Contra Costa County Flood Control District website.

New Development or Building Additions in Special Flood Hazard Areas must comply with the requirements of the Walnut Creek Municipal Code Section 9-12, Flood Damage Prevention. If all or part of your property is located in a Special Flood Hazard Area shown on the FEMA Flood Maps. Contact the Engineer on Duty at (925) 943-5839 to go over any special requirements that may apply for your project. You can protect yourself and your property by retrofitting your home. Click here for more information.

Reporting a Flooding Problem
If you observe flooding in your neighborhood, you can report it to the City by calling (925) 943-5854 weekdays. After hours, call (925) 943-5844. 


The City of Walnut Creek maintains the floodplain maps and will determine whether your property is within or outside the Special Flood Hazard Area (SFHA). This service is provided to homeowners, lending institutions, real estate agents and insurance agent.

To find out if a property is in the Special Flood Hazard Area (SFHA), please contact the Engineering Division at (925) 943-5839. You can also find out if you live in a Special Flood Hazard Area (SFHA) by reviewing the Flood Maps prepared by FEMA.