Flooding & Floodplains

The Federal Emergency Management Agency recently updated the floodplain maps for portions of Chester County. The new maps went into effect on September 29, 2017. To view the new interactive online FEMA floodplain maps, visit their Map Service Center website and type in the street address for the property of interest. Call FEMA Map Specialists at 1-877-FEMA-MAP.

You are also welcome to call us at the Chester County Water Resources Authority at 610-344-5400 or email us at wauth@chesco.org with any questions. 

FEMA's mapping of floodplains approximates where floodwaters may rise, however even if the property is outside of a FEMA floodplain, it may still flood. FEMA chose a "standard size" storm to approximate the floodplain map boundaries, and that storm was the 100-year flood event. However, a 100-year flood is not something that occurs once every 100 years. It is more accurate to refer to it as a 1% annual chance of the area flooding in any given year. A 100-year flood could occur twice in five years. The FEMA map also does not imply that properties outside of the 100-year floodplain will never flood. A devastating rainstorm can occur and many properties outside the 100-year floodplain may be flooded in any given year.

To better understand the location of the FEMA floodplain boundary to your property boundary, you can use ChescoViews. Click on "Find" to enter your address. Click on "TOC" and click on the "Flood Risk Mapping" to see the FEMA floodplain boundaries. You can also click on a box to see the two-foot contours if you are interested in the topography.

For information about FEMA floodplains and the National Flood Insurance Program (NFIP), visit FloodSmart.gov.
When purchasing flood insurance, you should check who the underwriter and their stability, whether the policy meets the NFIP standards, double-check that your elevation certificate is filled out properly for your property (this can affect what you pay) and read your policy's declaration page to make sure the agent accurately captured your property (ex. primary or secondary residence?).

For more information behind the science of the 100-year flood and floodplains, visit this USGS webpage.

Property owners can view a simplified floodplain map here

Call your local municipality, FEMA's Map Specialist at (877) FEMA MAP (1-877-336-2627), or Chester County at 610-344-5400 for help with any questions regarding FEMA floodplains. 

2017 Municipal Stormwater Summit & FEMA Flood Resiliency Meeting presentations



FEMA Floodplain Ordinance Reimbursement for Municipalities


Municipalities that have updated their floodplain ordinances can apply online for 50% reimbursement of costs through PA DCED's Municipal Reimbursement Program

FEMA Municipal Resources


Hazard Mitigation


Chester County Hazard Mitigation