Mitigation pays. It includes any activities that prevent an emergency, reduce the chance of an emergency happening, or lessen the damaging effects of unavoidable emergencies. Investing in mitigation steps now such as constructing barriers such as levees and purchasing flood insurance will help reduce the amount of structural damage to your home and financial loss from building and crop damage should a flood or flash flood occur.
What is a Flood?
Floods are the most common and widespread of all natural disasters - except fire. Most communities in the United States can experience some kind of flooding after spring rains, heavy thunderstorms, or winter snow thaws. Floods can be slow, or fast rising but generally develop over a period of days.
Dam failures are potentially the worst flood events. A dam failure is usually the result of neglect, poor design, or structural damage caused by a major event such as an earthquake. When a dam fails, a gigantic quantity of water is suddenly let loose downstream, destroying anything in its path.
What is a Flash Flood?
Flash floods usually result from intense storms dropping large amounts of rain within a brief period. Flash floods occur with little or no warning and can reach full peak in only a few minutes.
Find out if you live in a flood-prone area from the Emergency Management Department or the American Red Cross.
Ask whether your property is above or below the flood stage water level and learn about the history of flooding for your region. Learn flood warning signs and your community alert signals. Request information on preparing for floods and flash floods.
If you live in a frequently flooded area, stockpile emergency building materials.
These include plywood, plastic sheeting, lumber nails, hammer and saw, pry bar, shovels, and sandbags.
Have check valves installed in building sewer traps to prevent flood waters from backing up in sewer drains.
As a last resort, use large corks or stoppers to plug showers, tubs, or basins.
Plan and practice an evacuation route.
Contact the Emergency Management Department or the American Red Cross for a copy of the community flood evacuation plan. This plan should include information on the safest routes to shelters. Individuals living in flash flood areas should have several alternate routes.
Have disaster supplies on hand.
Develop an emergency communication plan.
In case family members are separated from one another during floods or flash floods (a real possibility during the day when adults are at work and children are at school), have a plan for getting back together.
Ask an out-of-state relative or friend to serve as the "family contact." After a disaster, it's often easier to call long distance. Make sure everyone in the family knows the name, address, and phone number of the contact person.
Make sure that all family members know how to respond after a flood or flash flood.
Teach all family members how and when to turn off gas, electricity, and water. Teach children how and when to call 9-1-1, police, fire department, and which radio station to tune to for emergency information.
Learn about the National Flood Insurance Program.
Ask your insurance agent about flood insurance. Homeowners policies do not cover flood damage.
If In a Car:
Flood dangers do not end when the water begins to recede. Listen to a radio or television and don't return home until authorities indicate it is safe to do so.
Check for gas leaks.
If you smell gas or hear a blowing or hissing noise, open a window and quickly leave the building. Turn off the gas at the outside main valve if you can and call the gas company from a neighbor's home. If you turn off the gas for any reason, it must be turned back on by a professional.
Look for electrical system damage.
If you see sparks or broken or frayed wires, or if you smell hot insulation, turn off the electricity at the main fuse box or circuit breaker. If you have to step in water to get to the fuse box or circuit breaker, call an electrician first for advice.
Check for sewage and water lines damage.
If you suspect sewage lines are damaged, avoid using the toilets and call a plumber. If water pipes are damaged, contact the water company and avoid using water from the tap. You can obtain safe water by melting ice cubes.
Information compiled from the Federal Emegency Management Agency.
Are you looking for ways to protect your home from flooding? There are many things you can do, depending on the flood hazard in your area, the characteristics of your property, and the zoning and building codes in your community. Some methods are fairly simple and inexpensive; others will require a professional contractor.
This homeowner's checklist will help you become familiar with what you can do. For more information about the costs and benefits of each method, talk to a professional builder, architect or contractor. You should also ask the Building Services department about building permit requirements.
Call your the Emergency Management Department or Building Services Department for information about flooding. Ask to see a flood map of your community. There may be a projected flood elevation for your neighborhood. This information will help you determine how much water is likely to come in.
Even if you have taken steps to protect your home from flooding, you still need flood insurance if you live in a floodplain. Homeowners' policies do not cover flood damage, so you will probably need to purchase a separate policy under the National Flood Insurance Program (NFIP).
It takes 30 days for a flood policy to take effect. This is why you need to purchase flood insurance before flooding occurs. If your insurance agent is unable to write a flood policy, call 1-800-638-6620 for information.
The main electric panel board (electric fuses or circuit breakers) should be at least 12" above the projected flood elevation for your home. The panel board height is regulated by code. All electrical work should be done by a licensed electrician.
Consider elevating all electric outlets, switches, light sockets, baseboard heaters and wiring at least 12" above the projected flood elevation for your home.
You may also want to elevate electric service lines (at the point they enter your home) at least 12" above the projected flood elevation.
In areas that could get wet, connect all receptacles to a ground fault interrupter (GFI) circuit to avoid the risk of shock or electrocution.
Have electrical wiring done by a licensed electrician.
For protection against shallow flood waters, the washer and dryer can sometimes be elevated on masonry or pressure-treated lumber at least 12" above the projected flood elevation. Other options are moving the washer and dryer to a higher floor, or building a floodwall around the appliances.
The furnace and water heater can be placed on masonry blocks or concrete at least 12" above the projected flood elevation, moved to inside a floodwall or moved to a higher floor. You have more options for protecting a new furnace. Ask your utility about rebates for new energy efficient furnaces. The rebate plus the savings in fuel costs could make the purchase feasible.
Furnaces that operate horizontally can be suspended from ceiling joists if the joists are strong enough to hold the weight. Installing a draft-down furnace in the attic may be an option if allowed by local codes. Some heating vents can be located above the projected flood elevation.
Outside air conditioning compressors, heat pumps or package units (single units that include a furnace and air conditioner) can be placed on a base of masonry, concrete or pressure treated lumber. All work must conform to state and local building codes.
A fuel tank can tip over or float in a flood, causing fuel to spill or catch fire. Cleaning up a house that has been inundated with flood waters containing fuel oil can be extremely difficult and costly.
Fuel tanks should be securely anchored to the floor. Make sure vents and fill line openings are above projected flood levels. Propane tanks are the property of the propane company. You'll need written permission to anchor them. Ask whether the company can do it first.
Be sure all work conforms to state and local building codes.
Install a floating floor drain plug at the current drain location. If the floor drain pipe backs up, the float will rise and plug the drain.
If flood waters enter the sewer system, sewage can back up and enter your home. To prevent this, have a licensed plumber install an interior or exterior backflow valve. Check with the Building Services Department for permit requirements.
You may have other options for avoiding flood damage depending on your needs and financial resources. These include building drainage systems around the property, sealing openings such as low windows, building levees, constructing exterior floodwalls around basement doors and window wells, improving exterior walls, elevating buildings above projected flood levels and relocating buildings away from floodplains. For more information, talk to a professional builder, architect or contractor. Ask the Building Services Department about building permit requirements.
Information compiled from the Federal Emegency Management Agency.
A flood can cause emotional and physical stress. You need to look after yourself and your family as you focus on cleanup and repair.
Turn off the electricity at the main breaker of fuse box, even if the power is off in your community.
Information compiled from the American Red Cross.
Your local government can tell you in which flood zone your property is located. For unincorporated Charleston County, Awendaw, Kiawah Island, Meggett, and Rockville, contact the Charleston County Planning Department to obtain a flood zone determination. Flood zone determinations are available for property in other municipalities in Charleston County through the applicable municipality.
Flood Insurance Rate Maps for Charleston County are also available on-line at the Federal Emergency Management Agency (FEMA) map service center.
Charleston County has experienced many hurricanes and other severe storms throughout our history, the most recent of which were Hurricanes Hugo in 1989 and Hurricane Floyd in 1999. The greatest threat for flooding in the Charleston County area is from storm surge associated with a hurricane from the Atlantic Ocean.
If a property within Charleston County is in one of the following flood zones:
Zone A: No base flood elevations determined.
Zone AE: Base flood elevations determined.
Zone AH: Flood depths of 1 to 3 feet (usually areas of ponding); base flood elevations determined.
Zone AO: Flood depths of 1 to 3 feet (usually sheet flow on sloping terrain); average depths determined. For areas of alluvial fan flooding, velocities also determined.
Zone A99: To be protected from 100-year flood by Federal flood protection system under construction; no base flood elevations determined.
Zone V: Coastal flood with velocity hazard (wave action); no base flood elevations determined.
Zone VE: Coastal flood with velocity hazard (wave action); base flood elevations determined.
Shaded Zone X: Areas of 500-year flood; areas of 100-year flood with average depths of less than 1 foot or with drainage areas less than 1 square mile; and areas protected by levees from 100-year flood.
Zone X: Areas determined to be outside 500-year flood plain.
Zone D: Areas in which flood hazards are undetermined, but possible.
Additional information regarding flood zones and flood insurance is available from the National Flood Insurance Program.
Federally subsidized flood insurance is available through the National Flood Insurance Program for most properties located in Charleston County and its inclusive municipalities. Damage caused by flooding is not covered by a standard homeowner's insurance policy. A separate flood insurance policy is required for flood peril coverage. Flood insurance is available for buildings only, contents only, or both buildings and contents. Insurance agents or the National Flood Insurance Program should be contacted for flood policy information. There is generally a 30-day waiting period for flood insurance policies to become effective. Charleston County currently has a few parcels of land that could potentially be developed located in "Coastal Barrier Resource Act" protected areas (COBRA zones). Under Federal law, the National Flood Insurance Program may not issue flood insurance policies for structures built in COBRA zones. If flood insurance is available for structures built in COBRA zones, it will be through a private insurer.
The Charleston County Flood Damage and Prevention Ordinance mandates that certain procedures be followed for construction-related work within properties designated as flood zones on the Charleston County Flood Insurance Rate Maps. Copies of this ordinance are also available from the Charleston County Building Services Department upon request.
The National Flood Insurance Program requires that if the cost of reconstructing, rehabilitating, adding to, or otherwise improving a structure equals or exceeds 50 percent of the building's assessed or appraised value, then the building must meet the same construction requirements as a new building. An improvement of 50 percent or more to a structure is known as a "Substantial Improvement". These requirements also apply to buildings that are substantially damaged; however, the value used in making the substantial improvement determination is the pre-damage value of the structure. In Charleston County and the jurisdictions for which it provides inspection-related services, the values of construction work on building permits taken out on a property during the past five (5) years are included in the determination of a "Substantial Improvement." This regulation is enforced through the construction permitting process. Any questions regarding "Substantial Improvements" may be referred to the Building Services Department.
Flood Elevation Requirements:
The finished floor of all new and substantially improved residential structures must be elevated to a minimum of one foot above the base flood elevation indicated on the applicable flood insurance rate map. A flood elevation certificate indicating this elevation must be submitted prior to any building inspection except for a foundation inspection. This certificate must be of the latest version available.
Only non-residential structures in all "A" flood zones may be floodproofed to a minimum of one foot above the base flood elevation in lieu of elevating the finished floor to this elevation. A pre-construction (prior to the plans being released for permit) and an as-built (prior to final building inspection) floodproofing certificate must be completed by a South Carolina registered Architect and/or Professional Engineer for all floodproofed buildings. Construction plans for floodproofed buildings must also be sealed by a South Carolina registered Architect and/or Professional Engineer.
Equipment Elevation Requirements:
With the exception of one electrical outlet and one switch on a Ground Fault Interrupter (as required to meet the National Electrical Code), there may be no electrical wiring, plumbing fixtures, mechanical fixtures, other equipment, appliances, or ductwork located within new or substantially improved structures below one foot above the base flood elevation. Replacement HVAC systems in all "A, AE, AH, AO, A99" flood zones must be located either at or above the existing finished floor elevation or the base flood elevation, whichever is lower, unless the property is undergoing a "Substantial Improvement," in which case the HVAC system must be elevated to or above one foot above the base flood elevation.
Construction Materials Requirements:
Per FEMA, only Flood Resistant Materials Technical Bulletin 2 (Class 4 or 5 materials) are permitted to be used below the base flood elevation unless the structure is a floodproofed non-residential structure.
Flood Control Vent Requirements:
Enclosed areas below the base flood elevation (e.g. garages, sheds, crawl spaces, etc.) must be provided with flood control vents located and sized in accordance with FEMA requirements (e.g. a minimum of two (2) openings on different walls, located within a maximum of 12 inches of grade, sized at a minimum of one square inch per one square foot of enclosed area, with vents that allow the free-flow of flood waters at all times. If these specifications are not met, a South Carolina registered Architect or Professional Engineer must certify in writing that the structure is designed to comply with FEMA requirements regarding equilization of hydrostatic and hydrodynamic forces.
Permitted Uses Below Base Flood Elevation:
Permitted uses below the base flood elevation are restricted to those necessary for building access, vehicle parking, and limited storage of yard-related equipment.
Refer to the Charleston County Flood Damage and Prevention Ordinance.
Lowest Horizontal Member Elevation:
The lowest horizontal structural member of all new and substantially improved structures must be elevated to a minimum of one foot above the base flood elevation indicated on the applicable flood insurance rate map. A flood elevation certificate indicating this elevation must be submitted prior to any building inspection, except for a foundation inspection. This certificate must be of the latest version available.
Plan and Certificate Requirements:
Wall section and foundation plans for structures in "V or VE" flood zones must be designed and sealed by a South Carolina Registered Professional Engineer and/or Architect. Plans must detail breakaway wall construction, foundation design, and scour depth. If spread footings are used, the bottom of the footing must be a minimum of 12 inches below the anticipated scour depth at the structure location. Pre-construction "V-Zone design" and "V-Zone Breakaway wall" certificates must be submitted with the construction plans for review. As-built "V-Zone design" and "V-Zone Breakaway wall" certificates must be submitted prior to a final building inspection. Obtain copies of these certificates from the Charleston County Building Services Department.
Equipment Elevation Requirements:
With the exception of one electrical outlet and one switch on a Ground Fault Interrupter (as required to meet the National Electrical Code), there may be no electrical wiring, plumbing fixtures, mechanical fixtures, other equipment, appliances, or ductwork located within new or substantially improved structures below the design flood elevation (base flood elevation plus freeboard). Replacement HVAC systems in all special flood hazard areas (flood zones) must be located either at or above the existing finished floor elevation or the design flood elevation, whichever is lower, unless the property is undergoing a "Substantial Improvement," in which case the HVAC system must be elevated to or above the design flood elevation.
Construction Materials Requirements:
Per FEMA, only Flood Resistant Materials Technical Bulletin 2 (Class 4 or 5 materials) are permitted to be used below the base flood elevation.
Permitted Uses Below the Flood Elevation:
Permitted uses below the design flood elevation are restricted to those necessary for building access, vehicle parking, and limited storage of yard-related equipment.
Walls Below the Base Flood Elevation:
All walls below the design flood elevation in a V or VE flood zone must be designed and certified by a South Carolina registered Professional Engineer and/or Architect to break away from a water load less than that which would occur during the base flood.
No fill is permitted to be used for structural purposes in "V and VE" flood zones. Landscaping fill is only permitted if a South Carolina registered Professional Engineer certifies in writing that the fill will not cause wave run-up or deflection.
No obstructions are permitted below the base flood elevation within a structure. Obstructions not located within a structure (e.g. permanent planters, elevated swimming pools, elevated tennis courts, certain types of fences, etc.) are also not permitted unless a South Carolina registered Professional Engineer certifies in writing that the obstructions will not cause wave run-up or deflection.
For properties located in Unincorporated Charleston County, Awendaw, Hollywood, Kiawah Island, Meggett, Ravenel, Rockville, and Seabrook Island, the Charleston County Building Services Department maintains copies of flood elevation certificates for all new construction and substantially improved structures. If your structure was constructed in one of these jurisdictions since 1990, the Charleston County Building Services Department may have an elevation certificate on file for your structure. For structures where an elevation certificate is not available on file, a S.C. Registered Land Surveyor will need to survey the elevation of the structure and complete the flood elevation certificate form. Charleston County does not survey structures for the purpose of completing flood elevation certificates.
The Charleston County Emergency Management Department has information available on safety measures for flooding and other hazard events. The Federal Emergency Management Agency also maintains an electronic library of resources on flood safety. The South Carolina Flood Mitigation Program office also provides information on flood safety. It is important to remember to not drive through flooded areas.
The Federal Emergency Management Agency maintains an electronic library of reference materials on topics such as retrofitting structures for enhanced flood and hurricane resistance and protecting building utilities from flood damages. The Charleston County libraries also have multiple publications available in their reference sections on protecting property from flood damages. Since Charleston County is subject to hurricanes, measures such as protecting glazed openings in your buliding against high wind damages should also be taken for property protection.
Charleston County has passed an ordinance prohibiting the dumping of trash, landscape debris or other materials into stream channels, ponds, basins or ditches that regularly carry or store stormwater in the unincorporated areas of Charleston County. These channels are routinely cleaned and maintained by the Charleston County Public Works Department. Residents of Unincorporated Charleston County are encouraged to assist in maintaining the drainage channels and ditches by removing or reporting obstructions (i.e. shopping carts, debris, trash, etc.) at (843)202-7600. Keeping drainage channels free of obstruction reduces flooding potential in the event of heavy rains.
First and foremost, make certain the building is structurally sound and is not going to collapse or cause other physical harm prior to entering a damaged structure. Shut off the electrical and/or gas service to the structure if there is any possibility that the service is damaged. Notify all applicable insurance carriers of the damage immediately to begin the claims process.
If your property is one of many damaged by an event, make sure the address of your property is clearly indicated for inspectors and insurance adjusters.
Take photographs of any damaged areas. Secure the property from any additional damages if possible. Wait for your insurance company to give you clearance to begin cleaning up damaged areas.
The Federal Emergency Management Agency also has information available online regarding the first steps to take after a flood and about repairing your flooded home. Be careful to avoid injury during post-event clean-up and salvage operations. Make sure any contractors you hire to repair your property are licensed or registered for the type of work they are performing and obtain applicable permits prior to starting work on your property.
Licensing and permit information is available from the Building Services Department.
Charleston County coordinates a regional planning initiative, involving the County and municipalities within Charleston County, in developing and maintaining the Charleston Regional Hazard Mitigation Plan. This plan is updated annually to reflect changes that have occurred during the year. Anyone who would like to provide input into the Charleston Regional Hazard Mitigation Plan may do so by e-mailing the Building Services Department at firstname.lastname@example.org, or by calling the department at (843)202-6930. The public is also invited to attend committee meetings regarding plan updates.
If you have any questions contact (843)202-6930.
Flood hazard areas in Charleston County may contain wetland areas which serve natural and beneficial functions such as flood moderation, water quality enhancement, ground water recharge, and habitat for wildlife. Beachfront areas may also contain primary ocean front dunes, which serve as buffers against minor wave height fluctuations and beach erosion. Protecting these areas maintains their important functions. Activities that disturb beachfront and saltwater wetlands should not be undertaken without first obtaining permits from the South Carolina Department of Health and Environmental Control Office of Ocean and Coastal Resource Management. Any disturbance of freshwater wetlands requires a permit from the U.S. Army Corps of Engineers and certification from S.C. DHEC's Office of Ocean and Coastal Resource Management.
The United States Geological Survey (USGS) has placed stream gages in rivers and streams that indicate real-time water elevations at the following locations within Charleston County:
For topographic map information please contact the Building Inspections Department.
These stream gage elevations are to be used for approximations only. Always follow emergency instructions that will be broadcast over local television and radio stations through the Emergency Alert System as weather advisories are released or updated by the National Weather Service. If evacuations are required, it is imperative that you follow instructions. Street patrols and door-to-door notifications may be used if an evacuation is mandatory. Generally, residents are given 48-72 hours notice in advance of a hurricane.
Charleston County also uses a telephone notification system for emergency information. For more information and free registration, please visit http://alert.charlestoncounty.org.
Questions regarding emergency procedures may be directed to the Charleston County Emergency Management Department.
City of Charleston
City of Folly Beach
City of North Charleston
City of Isle of Palms
Town of Awendaw
Town of Hollywood
Town of James Island
Town of Kiawah Island
Town of Lincolnville
Town of McClellanville
Town of Meggett
Town of Mount Pleasant
Town of Ravenel
Town of Rockville
Town of Seabrook Island
Town of Sullivan's Island
E-mail your comments or questions about this site to
Report technical problems with this site to email@example.com
This is the official web site for Charleston County Government.
Copyright © 2000-2017, Charleston County, South Carolina. All rights reserved.