Public Works and Environmental Services

CONTACT INFORMATION: Our administrative offices are open 8 a.m. – 4:30 p.m., Mon - Fri
703-324-5500 TTY 711
12000 Government Center Parkway
Suite 449, Fairfax, Va 22035
Joni Calmbacher
Director, Stormwater Planning

Flood Protection Newsletter

This newsletter includes important flood protection related information including flood safety, floodproofing, permit requirement, drainage service requests, special flood hazard areas, emergency alert systems, natural floodplain functions, and flood insurance.

If Your Property is In or Near a Floodplain

For information on floodplain locations, visit or call:

  1. FEMA’s Flood Map Service Center at FEMA Flood Map Service Center | Welcome!
  2. Fairfax County’s Digital Flood Insurance Rate Map at Digital Flood Insurance Rate Map | Public Works and Environmental Services.
  3. Fairfax County Stormwater Planning Division at 703-324-5500, TTY 711.

Residents are encouraged to prepare for storms and flooding:

  1. Sign up to receive emergency alerts at Alerts | Topics (
  2. Plan for your family and pets.
  3. Make copies of important documents.
  4. Prepare an emergency kit.
  5. Don’t drive through flood water.

Turn Around - Don’t Drown

To report storm drainage concerns or flooding, contact:

  1. Fairfax County Maintenance and Stormwater Management Division at 703-877-2800, TTY 711.
  2. Complete the form at Contact Maintenance and Stormwater Management | Public Works and Environmental Services.
  3. Review your homeowner’s insurance policy and/or contact your insurance agent to determine if your policy covers losses from flooding.
  4. For information on flood insurance visit The National Flood Insurance Program | FloodSmart.

Permits and Flood Proofing

Construction in a floodplain is not allowed under most circumstances. •

  • Before building, filling or excavating in a floodplain, or near any natural or man-made watercourse, call Land Development Services at 703-324-1720, TTY 711, to determine if the proposed activity is allowed and what types of permits are required.
  • Any construction or land disturbance within or adjacent to a natural or man-made watercourse may require a wetland permit from the U.S. Army Corps of Engineers and the Commonwealth of Virginia.
  • An addition to an existing building that is located in a floodplain may be allowed if the building was constructed prior to August 14, 1978, and the cost of the addition is less than 50 percent of the market value of the existing building, not including the land.
  • New dwellings and additions constructed adjacent to a floodplain must be elevated 18 inches above the 100- year flood level and set back 15 feet from the edge of the floodplain.
  • Existing buildings in floodplains that have been damaged by flood, fire or other casualty loss may be reconstructed.
  • A dwelling damaged to the extent that the cost of repairs equals or exceeds 50 percent of the market value of the building before it was damaged must meet the same requirements as a new building.
  • In addition to county approval, no building or filling is allowed in a floodplain without an engineering analysis to ensure the project will not increase flood damage elsewhere.

For more information call Land Development Services at 703-324-1720, TTY 711, or visit Land Development Services.

FEMA recommends several ways to protect a building from flood and wind damage:

  • Re-grade the lot to drain water away from the building.
  • Waterproof walls and install watertight enclosures over entrance ways. This is not recommended for houses with basements or if flood waters may exceed two feet.
  • Raise the house above flood levels. Flood waters may pass under the house, causing less damage.
  • Protect buildings from high winds during tropical storms and hurricanes by installing storm shutters and reinforced garage doors.

Any alteration to a building or land, including re-grading, filling or modifying a sewer line, requires a permit. For information regarding building and site regulations, call Land Development Services at 703-324-1720, TTY 711.

Some houses, including those that are not in a floodplain, may have sewers that back up into the basement occasionally during heavy rain. A plug for the basement floor drain, shower drain, or standpipes for these drains, may reduce or eliminate backups. Plugs are available at many hardware and plumbing supply stores. A plumber should be consulted when installing a plug, overhead sewer or back-flow valves. More information about flood proofing is available at Flood Information | Public Works and Environmental Services.

Flood Safety, Erosion, Service Requests

Flooding occurs in virtually every community, including Fairfax County. Flash floods are the most dangerous and may occur within a few minutes of excessive rainfall, a dam failure or a sudden release of water held by an ice jam. Flash floods often have a dangerous flow of water that may carry with it rocks, mud, tree limbs and other debris. Overland flooding occurs when rivers and streams overflow their banks. Occasionally, the capacity of stormdrains that are designed to carry stormwater away from streets and yards is exceeded.

For more information see the link at Flood Information | Public Works and Environmental Services.

In 2020, 59 people drowned in floods in the United States: 31 (53 percent) were male while 28 (47 percent) were female. Of the 59 fatalities, 37 were driving; 4 were walking/hiking; 8 were at home; 1 was boating; 4 fell in; 1 was working; and 4 were other flood-related fatalities according to the National Weather Service NWS Preliminary US Flood Fatality Statistics (

Flash flooding is the most dangerous type of flood as it combines the destructive power of the water with incredible speed and unpredictability.

In 2019, 93 people died in floods. Sixty-three were male (68 percent) and 30 were female (32 percent).

The majority of people who died in floods made one common and fatal mistake: they drove their vehicles including pickup trucks, vans and sport utility vehicles, into flood waters.

According to the U.S. Geological Survey, water that is one foot deep typically exerts 500 pounds of lateral force on a vehicle. Once the vehicle is floating, the floodwater becomes the steering wheel. If the water is moving, the vehicle may be swept away, tipped on its side or flipped over, trapping the occupants inside.

A bridge or road that cannot be seen under floodwaters may have been undermined or washed out.

Staff of the Northern Virginia Soil and Water Conservation District (NVSWCD) and of the Stormwater Management Program provide information and advice on private drainage and erosion problems. A free guidebook, “Solving Drainage and Erosion Problems: A Guide for Homeowners,” may be downloaded from Solving Drainage and Erosion Problems: A Guide for Homeowners | Northern Virginia Soil and Water Conservation District.

Call NVSWCD at 703-324-1460, TTY 711, visit Northern Virginia Soil and Water Conservation District (NVSWCD) or email

To report storm drainage system flooding, issues with a stormwater management pond or for a determination of who maintains a stormdrain, call the Maintenance and Stormwater Management Division at 703-877- 2800, TTY 711, or use the form at Contact Maintenance and Stormwater Management | Public Works and Environmental Services.

For more information, visit Storm Drainage System | Public Works and Environmental Services.

Special Flood Hazard Areas

The Federal Emergency Management Agency (FEMA) defines SFHAs as land areas that are at high risk for flooding.

These areas are indicated on Flood Insurance Rate Maps (FIRMs) and on Digital Flood Insurance Rate Maps (DFIRMs). To determine if a property is in a SFHA, visit Digital Flood Insurance Rate Map | Public Works and Environmental Services or FEMA’s Map Service Center FEMA Flood Map Service Center | Welcome!. FEMA initiated an update of the county’s 2010 FIRM and associated Flood Insurance Study (FIS) in 2016, and on April 30, 2021, provided the county with a preliminary FIRM and FIS with updated information. The County notified all residents affected by the proposed changes to the FIRM in October/ November 2021, and held a series of virtual meetings in January and February, 2022 to publicize the changes and receive comments on the proposed changes. FEMA initiated the appeal period for the preliminary FIRM and FIS on April 22, 2022. An appeal letter was submitted to FEMA on July 21, 2022. FEMA is currently reviewing the appeals. A revised preliminary DFIRM and FIS is expected in Fall 2023. A letter of Final Determination is anticipated sometime in 2024.

Flooding may occur at any time, with little or no warning. There are four main sources of local flood hazards: floodplains; rivers and streams during heavy storms; inadequate overland relief during heavy storms; and tidal surcharges in the lower Potomac River caused by hurricanes, tropical storms and earthquakes.

Properties in a floodplain or in a SFHA may flood at any time. Areas of flood hazards are identified on the 2010 Digital Flood Insurance Rate Maps | Public Works and Environmental Services.

In general, the SFHAs are labeled as Zone A or Zone AE.

Zone A is the area subject to inundation by the one-percent-annual-chance flood (also known as the base flood) event generally determined by using approximate methodologies.

Zone AE is the area subject to inundation by the one-percent-annual-chance flood event determined by detailed methodologies. Base Flood Elevations (BFEs) are shown on the FIRMs.

More information about Zones A and AE may be seen at Flood Zones |

  • Learn your flood hazard.
  • Beginning October 1, 2021, new policies and all policies renewing on or after April 1, 2022, are subject to the new rating methodology Risk Rating 2.0. More information may be seen at Risk Rating 2.0: Equity in Action |
  • Those who rent or lease property may purchase a ‘contents only’ policy.

  • Important documents and contact information
  • Food and water
  • Battery operated radio
  • Batteries, flashlight, solar chargers for cell phones
  • First aid kit, medications
  • Local maps
  • Emergency blankets
  • Change of clothes
  • Cash
  • Tools and duct tape
  • Can opener
  • Whistle and light sticks
  • Trash bags and sanitation supplies
  • Waterproof container

Alerts and Warning Systems

Be Prepared - Receive Emergency Alerts

New users may register their wireless devices and land lines with voice mail (home or business) at:

Alerts | Topics (

Please update your information at the link above.

The Fairfax Alerts system is specific to Fairfax County. Everyone who lives or works in the county is welcome to sign up for Fairfax Alerts to receive information about public safety, traffic, weather, police, emergency preparedness drills and exercises, flooding, Metro Safe Track, county news, Fairfax Connector, public meetings and events and other information from Fairfax County. The Fairfax Alerts system provides timely emergency information during a crisis and provides daily updates. Messages are delivered to registered devices that may include email accounts, text pagers, cell and satellite phones and other wireless devices. Register for emergency alerts from Fairfax County at

Residents may:

  • Choose weather, traffic and public safety notices.
  • Use the “do not disturb” feature.
  • Customize alerts relevant to home, school, day care and work.
  • Choose up to ten delivery methods.
  • Manage alerts by downloading the iPhone or Android app.

Please register with Fairfax Alerts at Alerts | Topics (

Fairfax Alerts

Sign up for Riverwatch Alerts at Fairfax Alerts. Select the Fairfax County Riverwatch option under subscriptions and click on Flood Preparedness Alerts; choose Huntington, Belle View, or New Alexandria.

Short messages are sent during critical situations to cell phones in a geo-targeted area. There is no need to sign up or download an app.

  • Imminent threats to safety or life, sent by state and local officials.
  • Extreme weather: tornados, flash floods, hurricanes or wind warnings issued by the National Weather Service.
  • Amber alerts: serious child abduction cases issued by the National Center for Missing and Exploited Children and the state police.
  • Presidential alerts during a national emergency.

Only On-Line Community Emergency Response Guide | Emergency Management (

The Fairfax County CERG is a guide that provides residents with the tools needed to be better prepared. The guide includes:

  • a family emergency plan.
  • a business or organization emergency plan.
  • a neighborhood preparedness plan.
  • an emergency supply kit check list.
Community Emergency Response Guide (CERG) cover art

Drainage, Litter, Library

Please help improve water quality by recycling trash and keeping storm drains clear.

Anything that is thrown from a vehicle, dropped on a parking lot or deposited into a storm drain is carried by rain or melting snow through the storm drainage system to streams, rivers and lakes; not to a wastewater treatment plant. This includes swimming pool water. Please do not drain pool water into a stream, manhole or storm drain. For more information about draining swimming pools, call 703-324-5500, TTY 711.

Litter blocks storm drains, which may cause street and yard flooding, traffic delays and property damage.

Cigarette butts, plastic and glass bottles, food containers, cans, plastic shopping bags and anything else that is not disposed of properly may flow to and pollute the Potomac River and ultimately the Chesapeake Bay.

Trash is unsightly. It degrades residential and commercial property values, harms the fish and other wildlife, and damages wetlands.

It is illegal to deposit anything into a storm drain. Fertilizer, pesticides, motor oil, pet waste, paint and paint-related products are hazardous to the environment and pollute the Potomac River, a source of drinking water for many Fairfax County residents.

The Fairfax County Municipal Code, chapters 124-1-1 through 124-1-13, contains provisions that address illicit discharges to state waters and the county’s storm drainage system.

Call 9-1-1 to report hazardous materials, such as those listed above, that have been discarded into a storm drain or stream. To obtain further information, please visit Polluted Runoff Inspections | Public Works and Environmental Services.

Plastic bottles and bags, food containers and a tire flowed with rainfall and snow melt to this creek in Fairfax County.
Plastic bottles and bags, food containers and a tire flowed with rainfall and snow melt to this creek in Fairfax County.

Plastic bottles and bags, food containers and a tire flowed with rainfall and snow melt to this creek in Fairfax County.

Printed information about flood protection for people, their property and their personal possessions is available at Fairfax County public libraries, in the reference section.

Visit Library (

Topics include:

  • Elevating Residential Structures.
  • Protecting Floodplain Resources.
  • Reducing Damage from Localized Flooding.
  • Protecting Building Utilities from Flood Damage.
  • Above the Flood: Elevating Your Flood Prone House.
  • Protecting Manufactured Homes from Floods and Other Hazards.
  • Answers to Questions About the National Flood Insurance Program.

Elevation Certificates, Insurance

Many residents received a “Letter D” from FEMA which states that “your property was built before your community’s first flood maps were issued, but now there is a flood map (Flood Insurance Rate Map) that shows the flood zone on your property. FEMA’s flood map informs floodplain management building requirements and the mandatory insurance purchase requirements. Starting October 2021, Risk Rating 2.0 will determine flood insurance premiums based on more advanced tools and capabilities that better reflect a property’s individual risk.

What is Risk Rating 2.0?

FEMA updated the NFIP’s risk rating process using a methodology known as Risk Rating (RR) 2.0. Insurance premium rates are changing to reflect risk more accurately under RR 2.0. Some existing policy holders will see rate decreases while others will see rate increases. Rates will be specific to each individual property’s geographic location and building characteristics.

What is not changing under RR 2.0?

Existing statutory limits on rate increases requiring that most rates not increase more than 18% per year will remain in place. FEMA will continue to offer premium discounts for pre-FIRM subsidized and newly mapped properties. FIRMs for mandatory insurance purchases and floodplain management will remain.

When does RR 2.0 go into effect?

Beginning October 1, 2021, new policies were subject to the new rating methodology. Also beginning October 1, existing policyholders eligible for renewal were able to begin taking advantage of immediate decreases in their premiums. All remaining policies renewing on or after April 1, 2022, are subject to the new rating methodology.

What are the flood risk variables considered in RR 2.0?

In RR 2.0, several flood risk variables such as flood frequency, multiple flood types (river overflow, storm surge, coastal erosion and heavy rainfall) and distance to a water source along with property characteristics such as elevation and the cost to rebuild will be considered in the policy premium.

Are elevation certificates (ECs) still being used?

Yes, but ECs are not required for agents to generate quotes or policies using RR 2.0, nor are they required to purchase an NFIP product. An EC can still be provided by a prospective insured, and an agent can enter its data into the RR 2.0 system, to see if it will lower the insured’s premium.

How will RR 2.0 affect me?

According to FEMA, some policyholders are paying more than their fair share while others (those with higher-valued homes) are paying less than they should. Under RR 2.0, it will be ensured that premiums are fair, based on the home’s flood risk. There will be lower premiums for the same coverage if you have a smaller home (replace cost value is factored into premium). Insurance payout after a flood will be more proportional to the premium paid.

If I sell my property, can the new owner also pay a lower, discounted rate?

Yes, if your flood insurance policy is continuous and you do not let your policy meet the lapsed policy criteria.

Call 1-888-379-9531 The National Flood Insurance Program | FloodSmart

National Flood Insurance Program logo


Fairfax County participates in the National Flood Insurance Program (NFIP) Community Rating System (CRS) sponsored by FEMA since 1993.

Participation in the CRS is a service for county residents and provides an opportunity for property owners to purchase flood insurance for their buildings and contents at discounted rates. Since 2014, Fairfax County maintains a Class 6 CRS Rating which results in flood insurance premium discounts of 20% for County residents.

A newly written policy on a compliant building in the County will receive the CRS discount when the policy is issued. If a newly written policy qualifies to receive a statutory discount (e.g., newly mapped, preFIRM), then those discounts will be applied to the policy in addition to a CRS discount. The CRS discount is applied to the total of the building, contents, and premium after any mitigation discounts (e.g., flood vents) and before any statutory discounts, annual increase cap, and fees, surcharges, and assessments.

In RR 2.0, because the flood zone is no longer a rating variable, the discount that had applied to just SFHA policies now applies to all policies. Also, even though ECs are not required for policies in RR 2.0, they are required to ensure compliance with community floodplain management building requirements, which can affect eligibility for CRS discounts as an EC shows the location of a building, its Lowest Floor Elevation (LFE), its building characteristics, and flood zone. ECs can also be used to support requests for a Letter of Map Amendment (LOMA) or Letter of Map Revision based on fill (LOMR-F). ECs can be prepared by any Virginia licensed land surveyor and may cost $800 to $2000. Call the Stormwater Planning Division at 703-324-5500, TTY 711, or Land Development Services at 703-324- 1720, TTY 711, for information about the ECs the County may have on file.

Flood insurance is mandatory for properties located in a SFHA that are financed with federally-backed mortgages. This includes all loans from banking institutions with deposits guaranteed by the Federal Deposit Insurance Corporation.

Flooding is the most common natural disaster in Virginia. Repairs are expensive. One inch of water in a home or office may cause significant damage. Most homeowners’ insurance policies do not cover losses from flooding.

Property owners and residents are encouraged to contact their insurance agent to determine the extent of their policy coverage.

Flooding may occur at any time of the year. After applying for flood insurance, typically there is a 30-day waiting period before coverage begins.

Renters may buy flood insurance for personal belongings or business inventory. Coverage may include cleanup expenses and repair or replacement of such items as furnaces, water heaters, washers, dryers, air conditioners and freezers.

Flood insurance benefits do not have to be repaid. Flood related claims may be covered even if a disaster was not declared. Flood insurance may cover homes and businesses and protect the property owner’s financial security.


Land use and development in Fairfax County is governed by the Comprehensive Plan, the Public Facilities Manual, the County Code and the Virginia Uniform Statewide Building Code. Fairfax County reviews all subdivision, site and grading plans and building permit applications to determine if the land is located in a floodplain.

The goal of floodplain-related requirements is to prevent loss of life and property damage, promote flood safety, preserve wildlife habitats and maintain the natural integrity of streams, protect water quality and increase groundwater recharge.

The county participates in the National Flood Insurance Program (NFIP). NFIP rules state that if the cost of reconstruction, rehabilitation, additions or other improvements to a building equals or exceeds 50 percent of its market value, then the building must meet the same construction requirements as a new building.

If a residence in a floodplain is damaged to the extent that the cost of repairs equals or exceeds 50 percent of the market value of the building (exclusive of the land) before it was damaged, the building must be constructed 18 inches above the base flood elevation.

It is important to note that an approved Letter of Map Amendment (LOMA) does not revise the FEMA or county floodplains.

Thank You!

The Stormwater Management Program

Stormwater Planning Division | Maintenance and Stormwater Management Division | Urban Forest Management Division

Frequently new updates are made to websites. If residents encounter difficulty accessing links in this newsletter, call the Stormwater Planning Division at 703-324-5500, TTY 711, or email

All photos by Fairfax County.

To request this information in an alternate format call 703-324-5500, TTY 711.

Fairfax Virtual Assistant