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Floodplain Information and Mapping

Floodplain inquiries are handled by the Department of Public Works and Transportation (DPWT), which coordinates mapping with the Federal Emergency Management Agency (FEMA). Although almost any part of Baltimore County can flood, there are some areas more likely to do so than others, called floodplains. Baltimore County floodplains fall into two main categories, tidal and riverine.

  • Tidal Floodplains—Areas influenced by the astronomical tides such as the Chesapeake Bay and the tidal rivers adjacent to it. Tidal flooding results primarily from wind and waves and although dangerous, their effect is limited to areas below certain elevations.
  • Riverine/Non-Tidal Floodplains—Those areas inundated by streams fed by rainfall and which flow downstream by gravity. Such flood plains can be even more dangerous than tidal since water flowing under gravity can build up considerable energy on its way downstream and can easily wash away buildings, vehicles and people. Little creeks and brooks flowing just a few feet wide and shallow enough to wade across during dry weather may become raging rivers many feet deep and hundreds of feet wide in a flood event.

Fortunately there are resources available to identify flood-prone areas so no one needs to be caught by surprise. For interpretation of the data contained on the below maps, call Terry Curtis at 410-887-3117 or email

Preliminary Flood Insurance Rate Map

In accordance with FEMA, a multi-year project to reexamine Baltimore County’s flood zones and develop detailed, digital flood hazard maps has been completed. The new maps—also known as Digital Flood Insurance Rate Maps (DFIRM)—reflect current flood risks, replacing maps that are up to 15 years old.

Interactive Floodplain Map Application

Use the online interactive mapping application to the Digital Flood Insurance Rate Map (DFIRM), which enables users to select, view and print predefined maps and reports about floodplains in Baltimore County. The data includes:

  • Floodplain data as published by FEMA
  • Data on Letters of Map Amendment (LOMA), Letters of Map Revision (LOMR) and all letters of map change, including the ability to download the LOMA

View instructions for using the application. For issues with the application, call David Freeman at 410-887-2434 or email


The data in the DFIRM have an effective date of September 26, 2008 and should be used to comply with the Baltimore County Code 2003, Title 04 Department of Public Works and Transportation, Subtitle 02 Flood Insurance Rate Maps, Authority: Sections 32-8-202(a) and 32-8-203(d). New tidal floodplain maps and regulations were effective May 5, 2014.

For Homeowners

The worst of the flood plains are mapped on the Federal Flood Insurance Rate Maps (FIRMs) published by FEMA. Zones designated as special flood hazard areas on these FIRMs show:

  • Where the probability of flooding is one percent or more in any particular year
  • All of the tidal floodplains, but generally, only map riverine flood lains draining rainfall on areas of one square mile (640 acres) or greater

Under Federal, law mortgage lenders must require flood insurance coverage for properties in these areas. It’s important to note that ordinary homeowners insurance does not cover flood damage at all.

Additional Resources

View Baltimore County's nuisance flooding plan, or learn more from the state and federal resources below:

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