Flood Damage Restoration in Cobb County, GA, Creek by Creek

Flood water does not arrive the way a leak does. It comes under the door from the street, down a sloped back yard into a basement stairwell, or over the bank of a creek that was ankle deep the day before. In Cobb County that history is measured, not remembered: federal stream gauges on Sweetwater, Noses, Nickajack, Noonday and Allatoona creeks all hold high-water marks from September 2009, when the county counts more than 1,600 homes flooded.

Water Damage Cobb County is a free referral service. It connects callers with independent local water damage restoration providers and is not a contractor, so the cleanup, drying and repairs described on this page are carried out by the provider you are connected with, on that provider’s own terms and prices.

This page covers water that came in from outside: a creek out of its banks, a storm drain that could not keep up, runoff through a basement wall or a window well. Water from a burst pipe, a water heater or an appliance is a different job with a different insurance answer, and it is covered under emergency water removal in Cobb County. Where a flood has pushed sewage up through floor drains, see sewage cleanup in Cobb County as well.

Safety before cleanup

Nothing in a flooded house is worth an injury, and most of the hazards are not visible from the doorway. The points below come from the CDC, FEMA and EPA flood guidance, and they apply before anyone lifts a wet rug.

• Treat the water as contaminated. The CDC’s floodwater safety page lists human and livestock waste and household, medical and industrial hazardous waste among the things floodwater can carry, and links exposure to wound infections, skin rash, gastrointestinal illness and tetanus. Do not wade in it if there is any other way.
• Deal with the electricity from a dry place. FEMA’s flooded basement fact sheet says to mark the breakers that feed the basement and shut that power off before going in. The CDC adds that if reaching the main switch means stepping into standing water, an electrician should turn it off, and that nobody should switch power on or off while standing in water.
• Keep the power off until it has been checked. The CDC says an electrician should check the home’s electrical system before the power is turned back on after a flood.
• If you smell gas, leave. CDC guidance is to close the main gas valve, open the windows and get out of the house at once.
• Look up and down before walking in. The joint federal mold guide tells people entering a water-damaged home to look for sagging ceilings or floors and to watch for wet, muddy or slippery floors.
• Air out a closed-up house. A house shut for several days after flooding should be opened and left to air for at least 30 minutes before anyone stays inside, according to the CDC.
• Wear the gear if you must handle wet material. Federal guidance gives an N-95 respirator, goggles and protective gloves as the minimum, and the CDC adds rubber boots for anyone who has to enter floodwater. Children should not take part in cleanup, and pets belong elsewhere until the floor is dry.
• Run generators outside. EPA says fuel-powered generators give off deadly carbon monoxide and must run outdoors, at least 20 feet from buildings, never in a home, garage or shed.
• Leave a flooded heating and cooling system off. EPA says a system touched by flood water must not be used to help dry the house.

Where Cobb County floods, creek by creek

Cobb County drains in two directions. Creeks in the south and east, among them Sope, Nickajack and Sweetwater, run to the Chattahoochee River, which forms the county’s southeastern border. Creeks in the north, including Noonday, Butler, Proctor and Allatoona, run to Lake Allatoona.

In September 2009 both sides flooded at once. The U.S. Geological Survey dates the rain to September 16 to 22, with the most intense period late in the evening of September 20, and the National Weather Service estimates that 10 to 20 inches fell in under 24 hours on September 20 and 21. Cobb County’s Stormwater Management Division says the flood reached more than 1,600 homes countywide.

The table gives the peak at each gauge, taken from USGS records, with the page on this site that covers the city beside that water.

Creek and gauge	September 2009 peak	What the record says	Local page
Sweetwater Creek near Austell	30.82 feet on September 22	USGS: beyond the 0.2 percent (500-year) flood. NWS: 20 feet above flood stage and nine feet above the previous record crest.	water damage restoration in Austell, GA
Sweetwater Creek at Brownsville Road, Powder Springs	31.40 feet on September 21	USGS: exceeded the 0.2 percent annual chance flood.	water damage restoration in Powder Springs, GA
Powder Springs Creek near Powder Springs	About 19.9 feet on September 21	Two USGS publications differ by a tenth of a foot, so the stage is given as approximate.	Powder Springs page
Noses Creek at Powder Springs Road	23.2 feet on September 22	From the USGS summary of the flood, which lists a stage and no flow.	Powder Springs page
Nickajack Creek at US 78/278 near Mableton	19.85 feet	Almost 10 feet above the 10-foot flood stage. USGS dates the peak September 21 and NWS September 22. The gauge is downstream of Smyrna.	water damage restoration in Mableton, GA and water damage in Smyrna, GA
Sope Creek near Marietta	18.35 feet on September 21	The highest peak flow in a USGS record that begins in 1963.	water damage restoration in Marietta, GA
Butler Creek at Mack Dobbs Road near Kennesaw	14.27 feet on September 21	USGS: exceeded the 0.2 percent annual chance flood.	water damage restoration in Kennesaw, GA
Noonday Creek at Shallowford Road	19.66 feet on September 21	USGS: exceeded the 0.2 percent annual chance flood. The creek begins near Kennesaw Mountain and ends at Lake Allatoona.	Kennesaw page
Allatoona Creek at Stilesboro Road near Acworth	23.90 feet on September 21	USGS: exceeded the 0.2 percent annual chance flood.	water damage restoration in Acworth, GA
Chattahoochee River at Atlanta	28.12 feet on September 21	USGS: the highest stage in 81 years of continuous record at that gauge.	water damage in Cobb County

USGS found that the floods on Sweetwater, Butler and Powder Springs creeks greatly exceeded the estimated 500-year flood, and put the odds of what parts of Cobb and Douglas counties saw at less than 1 in 500 in any given year. On the north side, the agency says the flows on Allatoona, Noonday and Butler creeks raised Allatoona Lake more than 13 feet above full pool.

The Weather Service’s notes for the Austell gauge explain how far creek water can travel from the main channel. At a stage of 20 feet on Sweetwater Creek, it says, Powder Springs, Noses and Olley creeks back up into nearby neighborhoods. The 2009 crest was more than 10 feet above that level.

For the scale of the whole event, the National Weather Service counts more than 20,000 homes, businesses and other buildings with major damage across Georgia, 16,981 of them residences, and says the state’s property damage estimate was eventually raised to $500 million.

It was not a one-off

September 2009 is the flood these gauges are known for, but it is not the only high water in the public records. Four other events show up in the same files.

• July 2005, the remnants of Hurricane Dennis. Noonday Creek reached 16.30 feet late on July 10. Nickajack Creek near Mableton peaked at 16.56 feet on July 11, into the moderate flood range, and Sweetwater Creek near Austell crested at 21.81 feet on July 12.
• September 7 and 8, 2021. The National Weather Service says storms training over the northern Atlanta metro area caused significant flash flooding overnight, with radar estimates of as much as 4 to 5 inches in an hour and about 9 inches in a day just east of Marietta. Sope Creek reached 18.05 feet on September 8, its second-highest peak flow on record, and Rottenwood Creek near Smyrna had its highest recorded flow on that date too, at 14.67 feet, above its 2009 mark.
• Late August 2023. Rottenwood Creek reached 12.27 feet on August 29 and Nickajack Creek 11.95 feet on August 30. FEMA’s flood insurance records hold 22 claims from Smyrna’s two main ZIP codes with loss dates of August 28 to 30, the largest cluster on record for those ZIP codes.
• September 27, 2024, the remnants of Hurricane Helene. Nickajack Creek near Mableton peaked at 15.83 feet, its highest stage since September 2009, and Sweetwater Creek near Austell crested at 14.33 feet the next day.

You do not need a creek to flood

The gauges tell only part of the story. FEMA’s public flood insurance claims data held 129 claims from Smyrna’s two main ZIP codes, 30080 and 30082, when it was checked on October 5, 2026, with records going back to 1981. FEMA coded 66 of them as accumulation of rainfall or snowmelt and 27 as stream, river or lake overflow: about half were rain with nowhere to go, and about one in five was a creek. FEMA notes that this dataset is not an official federal report.

The flood map did not predict them either. Of those 129 claims, 57 were on properties rated in zones X, B or C, which lie outside the mapped Special Flood Hazard Area. Cobb County quotes a wider FEMA figure that points the same way: 40 percent of flood insurance claims filed through FEMA between 2015 and 2019 came from outside high-risk flood areas.

In practice this is the house at the low end of a cul-de-sac, the lot below a neighbor’s driveway, or the street where a culvert plugs with debris during a downpour. The water is shallow and gone in hours, but it has been through yards, roads and drains before it reaches the carpet, and a provider will usually treat what it soaked accordingly.

Who looks after drains and channels in Cobb

A restoration provider deals with the water inside the building. The drain, ditch or pond that sent it there belongs to someone else, and in Cobb County the answer depends on where it sits.

Where the drainage problem is	Who it goes to
Outside the road right-of-way, in unincorporated Cobb	Cobb County Water System, Stormwater Management Division
Inside the road right-of-way	Cobb County Department of Transportation
An open channel or storm drain on private property that was never dedicated to the county	The property owner. The county says its stormwater division is not funded to maintain these.
A detention pond serving a commercial or industrial site	The owner, at the owner’s cost, under Cobb County Code Section 50-112a
Inside a city’s limits	Ask the city which office takes the report; the county offices above cover unincorporated Cobb

The county lists the current numbers for both of its offices on the Cobb County Water System contact page.

A flood claim and a pipe claim go to different policies

The Insurance Information Institute offers a rule of thumb that sorts most cases. Water that comes from the top down, such as rainfall and burst sprinklers, is generally covered by a standard homeowners policy. Water that rises from the ground up is a matter for a flood policy.

That distinction matters before any cleanup starts, because it decides who is asked to pay, what has to be documented and how the water itself is classed. General summaries of the restoration trade’s category system list rising water from rivers or streams among the sources of Category 3 water, the most contaminated class, alongside sewage. Category 3 means more material is removed and less is dried in place.

Rain is not treated the same way by default. On March 16, 2026 the consensus body behind the S500 water damage standard issued a position statement that rain driven in from above and other weather-related water is not automatically Category 3, and that the category has to be based on the conditions actually found at the loss. A roof that leaked in a storm and a living room that took creek water can therefore be two different jobs under two different policies, even when they happened the same night.

The practical step is to tell both the insurer and the provider exactly where the water came from and how high it reached, and to say so before material is thrown out.

Flooded basement cleanup in Marietta and across Cobb

A room below grade floods in ways an upper floor cannot. Runoff comes down a slope and finds the stairwell or a window well, a sump pump stops when the power does, or a floor drain backs up when the pipe it empties into is full. No public source gives the number of basements in Cobb County, but FEMA’s records show they are part of the picture: 35 of the 129 flood claims from the two Smyrna ZIP codes record a finished or unfinished basement or enclosure, and many records leave that field blank.

Calls about a flooded basement in Marietta are handled the same way whether the house is inside the city or carries a Marietta mailing address in unincorporated East Cobb. What changes is the office that issues permits for the repair, which is set out on the page for water damage restoration in Marietta, GA.

FEMA’s rule for pumping a basement

The instinct is to pump a full basement dry as fast as possible. FEMA’s flooded basement fact sheet says not to, and gives a sequence.

1. Mark the breakers that feed the basement and shut that power off before going in.
2. Mark the water level on the wall, then pump the water down one foot.
3. Wait 24 hours and check the mark.
4. If the water has come back up, the ground outside is still saturated and it is too early to continue.
5. Once the level has stayed down, pump out two to three feet of water every 24 hours until the basement is empty.

Once the water is out, the provider typically removes what cannot be cleaned. FEMA’s guidance is that soaked wallboard is cut out to one foot above the water mark, that all wet insulation comes out, and that soaked carpet is discarded; the CDC puts carpet padding on the same list. Bare concrete and block are then washed, disinfected and dried.

Basements also have their own insurance gap. FEMA’s National Flood Insurance Program says its policies do not cover personal property kept in a basement, and do not pay for temporary housing or additional living expenses while the home is repaired. A finished basement full of furniture is the part of a flood loss most likely to fall to the owner.

What a flood restoration job involves

Each independent provider sets its own scope and method, so the order below describes how the work generally runs, not a promise about any one job. Where a federal agency has published guidance on a stage, it is named.

• Inspection and moisture readings. Moisture meters and infrared imaging are the usual tools for finding water behind walls and under floors, since FEMA notes it can sit out of sight in wall cavities, ducts and basements.
• Pumping and extraction. Standing water comes out first, with pumps and wet vacuums, once the electrical supply has been made safe.
• Removal of soaked porous material. Anything that absorbed flood water and cannot be cleaned is cut out and bagged.
• Washing, then disinfecting. The CDC’s step is to wash wet surfaces with hot water and detergent. FEMA is specific about the order: disinfectants are meant for surfaces that have already been cleaned.
• Drying. Dehumidifiers and air movers run until the structure reads dry, with readings taken as the work goes on.
• Mold prevention. Drying fast is the prevention. Where growth has already started, the job changes, as the next section explains.
• Repairs. New insulation, wallboard, flooring and trim go in only after the framing is dry.

What stays and what goes

Material	Usual outcome after flood water	Where the guidance comes from
Drywall and insulation contaminated by floodwater	Removed and discarded, not dried in place	CDC
Soaked wallboard	Cut out to one foot above the water mark and discarded	FEMA
Wet insulation	All of it comes out; only rigid insulation can be disinfected, dried and put back	FEMA
Mattresses, carpet, carpet padding, rugs, upholstered furniture	Thrown away when they cannot be cleaned and completely dried within 24 to 48 hours	CDC and the joint federal mold guide
Furniture made of pressed particle material	Treated as porous: when in doubt, it goes	FEMA
Ceiling tiles	Discarded and replaced	EPA and FEMA
Wood studs and framing	Cleaned, then dried; counted as dry below 15 percent moisture content	FEMA; flood cleanup guide linked by Georgia DPH
Solid wood furniture and other hard surfaces	Washed and kept	FEMA

Age changes the demolition. EPA warns that older homes may contain asbestos or lead in their building materials, which matters before walls, ceilings or flooring are torn out. Census Bureau estimates put about 5 percent of Cobb County’s housing units, roughly 16,300 homes, before 1960, and in the City of Austell the share is about 14 percent.

For the rebuild, FEMA recommends water-resistant materials in rooms that may flood again: tile, stone, sealed concrete, galvanized or stainless hardware and waterproof wallboard. That is a conversation to have with the provider and the insurer before the walls are closed.

Timing and mold after a flood

The federal agencies agree on the clock. FEMA says mold colonies can start to grow on a damp surface within 24 to 48 hours, and the joint guide from the CDC, EPA, FEMA, HUD and NIH says a flooded home that was not dried within 24 to 48 hours should be assumed to have mold growth.

Drying has its own published figures. FEMA says a wet or contaminated area usually takes two to three days to dry completely and that rebuilding should wait until then, while HomeAdvisor’s guide, updated June 17, 2026, estimates around five days for a water-damaged home depending on the damage. Those are general figures from those sources. Neither this site nor any provider can say how long a given house will take before readings are taken in it.

One instruction surprises people: once mold is visible, do not run fans. FEMA’s guidance is that fans can spread existing mold, so the approach shifts from drying to containment and removal, which is covered under mold remediation in Cobb County.

Flood insurance, stated correctly

FEMA puts it in one sentence: most homeowners insurance does not cover flood damage. Cobb County tells its residents the same thing, and the City of Powder Springs states that a homeowner’s policy does not cover flood losses. Cover for rising water comes from a separate flood policy, most often through the National Flood Insurance Program.

• The wait. An NFIP policy takes effect 30 days after purchase. FEMA’s exceptions are a policy bought while making, increasing, extending or renewing a mortgage, and a one-day wait when a property has been newly mapped into a high-risk zone and the policy is bought within 12 months of the map change.
• The limits. For a home, $250,000 for the building and $100,000 for contents, bought as two separate coverages.
• Mold. NFIP policies do not cover mold damage, so a policyholder is expected to do everything possible to stop it growing and spreading.
• The requirement. Georgia’s Environmental Protection Division says owners of property in a Special Flood Hazard Area in a participating community must buy flood insurance if they have a mortgage from a federally regulated or insured lender.

FEMA’s own list of what a flood policy covers and leaves out is on its FloodSmart coverage page.

Community discounts across Cobb County

Communities that go beyond the minimum floodplain rules earn their policyholders a premium discount through FEMA’s Community Rating System. FEMA says each class improvement is worth a further 5 percent for properties in the Special Flood Hazard Area, starting from 5 percent at class 9. The classes below are the ones that could be confirmed from public records.

Community	Rating class	What the record shows
Unincorporated Cobb County	Class 7	The county says residents receive a 15 percent discount. FEMA’s record shows 15 percent inside the Special Flood Hazard Area and 5 percent outside it.
City of Marietta	Class 7	FEMA’s Community Status Book, in its report dated October 5, 2026, shows 15 percent.
City of Austell	Class 5	25 percent for policyholders inside the Special Flood Hazard Area, per the city and FEMA’s list effective October 1, 2026.
City of Powder Springs	Class 6	The rating the city gives on its own flood protection page.
City of Smyrna	None listed	FEMA’s record shows no class for the city.
City of Kennesaw	None listed	FEMA’s table shows no class for the city.
Cities of Acworth and Mableton	Not confirmed	Ask your insurance agent which community rating applies to the address.

A class can change at any review and the discount depends on the policy, so treat the table as a reason to ask your agent the question, not as a quote.

Documenting a flood claim

• Photograph and video the damage before anything is moved. FEMA asks for photos and video of damaged property.
• Record the make, model and serial number of appliances and electronics.
• Keep samples of damaged carpet, flooring and curtains. FEMA says items that pose a health risk can be thrown away once they are documented.
• Contact the insurer at once, but do not wait for the adjuster before removing wet and moldy materials. That advice comes from the flood cleanup guide the Georgia Department of Public Health links to.

How to check your flood zone

Cobb County’s flood maps page sends residents to the FEMA Flood Map Service Center at msc.fema.gov and tells them to enter 13067C in the FEMA ID box to find the county’s flood risk products. The county also offers its own floodplain search tool on that page. Marietta points its residents to the Georgia DFIRM map viewer, the state flood map site that Georgia’s Environmental Protection Division also names for property-specific lookups.

Zone on the map	What it means
A and AE	Inside the Special Flood Hazard Area: land covered by the flood with a 1 percent chance in any year. The county calls it an area at high risk of flooding.
X, shaded	Between the limits of the 1 percent and the 0.2 percent annual chance floods.
X, unshaded	Above the level of the 0.2 percent annual chance flood.

No zone letter on the map means a property cannot flood. The Smyrna claim records above include 57 claims on properties rated outside the hazard area, and the 2009 flood passed the 0.2 percent level at gauge after gauge.

For live levels, the National Weather Service runs gauges with published flood stages on two south Cobb creeks. On Sweetwater Creek near Austell the stages are 8 feet for action, 10 for minor flooding, 13 for moderate and 17 for major. On Nickajack Creek near Mableton they are 8, 10, 16 and 21 feet, and the Weather Service notes that parts of Nickajack Park begin to flood at 10 feet and water has entered several homes by 18.

Permits and the 50 percent rule

Repairing a flooded house in a mapped floodplain is regulated work. Cobb County says all development in the floodplain requires a permit and directs owners to the Division of Development and Inspections in its Community Development agency. It also explains the federal test for substantial damage: when the cost of restoring a building equals or exceeds 50 percent of its fair market value before the damage, elevation is the only retrofitting method allowed.

The cities inside the county apply their own versions, and the differences are in how the costs are counted.

Jurisdiction	What its published rule says
Unincorporated Cobb County	Permit for all development in the floodplain. At 50 percent of pre-damage market value, elevation is the only retrofit allowed.
City of Marietta	If redevelopment costs reach 50 percent of the primary structure’s fair market value over any 10-year period, a property already in the floodplain must be brought up to code.
City of Austell	Substantial improvement is counted cumulatively over a twelve-year period, against 50 percent of market value.
City of Powder Springs	The city says permits are required for any flood damage repair work on a home.

For Smyrna, Kennesaw, Acworth and Mableton, ask the city’s building office before work starts. A provider can describe the repair, but the permit decision belongs to the office that issues it, and the owner should confirm it directly.

What flood restoration costs

Water Damage Cobb County has no prices. The provider you are connected with inspects the loss and prices it, and what moves the number is predictable: the area that got wet, how deep the water was, how contaminated it is, how long it stood, how much material has to come out and how much is rebuilt afterward.

The published figures below are context, each from the source named beside it.

Figure	Amount	Source and what it is
National average, water damage restoration	$3,868	HomeAdvisor, updated June 17, 2026. A national estimate, not a Cobb County price.
Typical national range	$1,383 to $6,369	HomeAdvisor, same date. Its full range runs from $450 to $16,000.
Black water (Category 3) cleanup	About $7.50 a square foot	HomeAdvisor, same date, against about $3.50 for clean water and $5.25 for gray water.
One inch of water in a home	More than $25,000 in damage	Cobb County’s flood insurance page.
Flood insurance building payments, late August 2023, Smyrna ZIP codes 30080 and 30082	About $5,100 to about $93,600 across 18 payments; median near $18,800	Arithmetic on FEMA’s public claim records. These are insurance payments, not contractor prices.

The Smyrna payments are the nearest thing to local evidence, and their spread is the useful part: the same few days of storms in the same two ZIP codes produced payments more than eighteen times apart. A flood job is priced on what is found in the house.

Renters, landlords and businesses

In a rented home the building is the owner’s to insure and repair, and the tenant’s belongings are the tenant’s own. The City of Powder Springs makes the point on its flood protection page: renters in a flood zone can insure their belongings. A renter standing in water should tell the landlord or property manager first, because a provider needs the consent of whoever is entitled to authorize work on the building.

The service connects landlords, property managers and businesses as well as homeowners. Commercial owners in unincorporated Cobb carry one further duty worth knowing after a flood: under County Code Section 50-112a, the detention pond or other stormwater facility serving a commercial or industrial site is the owner’s to maintain at the owner’s expense.

Checking the provider, and what happens when you call

Floods bring strangers to the door. The Georgia Attorney General’s storm alerts tell homeowners to avoid door-to-door offers of home repair work, and warn against any contractor who asks for full payment up front, takes only cash or refuses to give a written contract. The City of Powder Springs gave its residents the same warning about door-to-door repair sales in its 2024 flood notice.

Every provider reached through this site is independent, and it is the owner’s job to verify them. Ask for proof of insurance and a written contract, and ask who holds the license for the rebuild: the Attorney General’s office says general contractors, electricians, plumbers and heating and air conditioning contractors must be licensed in Georgia. An offer to pay your insurance deductible can, according to the same office, be the sign of a scam.

Georgia’s price gouging law applies during a state of emergency declared by the Governor, and only to the goods and services the Governor identifies. Outside a declared emergency, the protection is a written price agreed before work begins.

The call itself is free. It connects you with a participating independent provider that serves the area, and you decide whether to hire them. Many participating providers offer emergency response after hours, but availability depends on the provider and the demand at the time, which in a flood can be heavy, and no arrival time is promised here.

Questions people ask