Kennesaw, Marietta, and Acworth vs. Unincorporated Cobb County Taxes
Does It Cost More to Buy in Kennesaw, Marietta, or Acworth Than in Unincorporated Cobb County?
Yes, in most cases, and the gap is bigger than a lot of buyers expect. The City of Kennesaw's 2026 millage rate runs about 39.28 mills and Acworth's runs about 39.08 mills, both roughly nine mills higher than unincorporated Cobb County's 30.13 mills, because you are paying the county rate plus a separate city tax layered on top. Marietta is the exception: its own city schools millage largely offsets the added city police and fire millage, landing the total around 31.1 mills, close to unincorporated Cobb. The bigger issue is not just the rate. Cobb County, the City of Marietta, and the City of Kennesaw have each opted out of Georgia's 2024 statewide homestead exemption freeze, House Bill 581, and rely on their own, narrower exemptions instead, so which freeze actually applies to a given address depends on exactly where that address sits.
TL;DR
- Unincorporated Cobb County's 2026 millage rate runs about 30.13 mills. Kennesaw runs about 39.28 mills and Acworth about 39.08 mills, each roughly nine mills higher because a separate city tax sits on top of the county rate.
- Marietta is the outlier. Its own Marietta City Schools millage of 17.97 mills replaces the county school millage, bringing its total to roughly 31.1 mills, close to unincorporated Cobb despite Marietta running its own police and fire departments.
- Cobb County's Board of Commissioners voted 4-0 in February 2025 to opt out of the statewide House Bill 581 floating homestead exemption, and the county relies on its own, older floating exemption instead, which freezes only the county portion of your bill.
- The City of Marietta and the City of Kennesaw have also opted out of House Bill 581, in favor of their own local exemption rules. Acworth's specific position has not been clearly documented in public reporting as of this writing, so confirm directly with Acworth City Hall before you assume how an exemption will apply.
- Two homes a half mile apart, one inside city limits and one in unincorporated Cobb County, can carry a meaningfully different long term tax trajectory even at an identical purchase price.
Why City Limits Change Your Millage Rate
A millage rate is the tax rate applied per $1,000 of a property's assessed value, and in Cobb County it stacks in layers. Every property pays the county's base millage. If that property sits inside an incorporated city, it also pays that city's own millage on top, and depending on the city, a different school millage as well.
Here is the approximate 2026 breakdown:
| Jurisdiction | Approximate 2026 Millage | What It Covers |
|---|---|---|
| Unincorporated Cobb County | 30.13 mills | County government and county schools only |
| City of Kennesaw | 39.28 mills | County rate plus 9.15 city mills |
| City of Acworth | 39.08 mills | County rate plus 8.95 city mills |
| City of Marietta | approx. 31.1 mills | County rate (minus county school millage) plus Marietta's own police, fire, and the 17.97 Marietta City Schools millage |
These figures move slightly year to year as each jurisdiction sets its budget, so treat them as a snapshot rather than a locked-in number for your specific closing.
Kennesaw and Acworth: A City Tax Stacked on Top of the County Rate
If you are comparing a home inside Kennesaw city limits to a comparable home in unincorporated Cobb County, the Kennesaw home is carrying an extra 9.15 mills purely for being inside the city. The same pattern holds in Acworth, where the city adds 8.95 mills on top of the county rate. On a home assessed at $350,000 (after Georgia's 40% assessment ratio, that is roughly $140,000 of taxable value), nine extra mills works out to about $1,260 a year, every year, for as long as you own the home.
Marietta: A Different Formula, Not Necessarily a Different Bill
Marietta does not follow the same pattern. Because the city runs its own independent school system, Marietta City Schools, residents pay that system's millage instead of the Cobb County School District's millage. That swap mostly cancels out the extra city police and fire millage, which is why Marietta's total lands close to unincorporated Cobb County's rate rather than stacking on top of it the way Kennesaw and Acworth do.
HB 581 and Why the Exemption Freeze Depends on the Address
House Bill 581, passed by the Georgia legislature in 2024, created a statewide floating homestead exemption designed to cap how much a home's assessed value can climb each year for tax purposes. Counties, cities, and school systems each had until March 1, 2025 to decide whether to opt into the state exemption or opt out and keep their own existing exemption rules.
Cobb County's Board of Commissioners voted 4-0 in February 2025 to opt out, choosing to rely on the county's own, pre-existing floating homestead exemption instead. That older county exemption only freezes the county government portion of a tax bill, not the city or school portions. The City of Marietta and Marietta City Schools both opted out as well, and the City of Kennesaw issued its own formal notice of intent to opt out around the same time.
Acworth's specific decision on House Bill 581 is not clearly documented in the public reporting available as of this writing. If you are comparing a home in Acworth to one in Kennesaw, Marietta, or unincorporated Cobb County, do not assume the exemption rules match. Confirm Acworth's current position with Acworth City Hall or the Cobb County Tax Assessor's office before you factor it into your decision.
This matters because the opt-in and opt-out decisions are made separately at the county, city, and school district level. A home in unincorporated Cobb County answers to the county's exemption rules alone. A home inside Kennesaw or Marietta answers to the county's rules for the county portion of the bill and a separate, possibly different, set of rules for the city portion. That stacking is exactly what makes two homes a half mile apart carry different long term tax trajectories, even when they sell for the same price today.
What This Actually Means for Your Offer
None of this should talk you out of a home in Kennesaw, Marietta, or Acworth. It should change how you compare two listings that look similar on paper. A $450,000 home in unincorporated Cobb County and a $450,000 home inside Kennesaw city limits are not actually the same purchase once you run the full tax math, and the gap compounds every year you own the home.
Before you write an offer, especially if you are weighing properties across different jurisdictions, ask for:
- The property's current tax bill and which jurisdiction's millage it reflects.
- Whether the seller's homestead exemption transfers, carries over, or resets when you buy (in most cases, a homestead exemption does not transfer to a new owner, and your first full year's bill is calculated fresh).
- The specific city and school millage rates in effect for the current tax year, since these are set annually and can shift.
As a Certified Residential Appraiser, this is the kind of comparison I run for buyers before they write an offer, not after they get a surprise tax bill the following year. If you are weighing a home in Kennesaw against one in unincorporated Cobb County, or trying to decide between neighborhoods in Acworth and Marietta, I can pull the actual current millage figures and homestead exemption rules for the specific addresses you are considering, so you are comparing real numbers instead of assumptions.
Frequently Asked Questions
Does it matter whether I buy in the city of Kennesaw or unincorporated Cobb County?
Yes. A home inside Kennesaw city limits carries the county's millage rate plus Kennesaw's own city millage, about 9.15 additional mills in 2026. A comparable home in unincorporated Cobb County pays the county rate only, so the city home's tax bill runs several hundred to over a thousand dollars higher per year, depending on assessed value.
Why is Marietta's property tax rate closer to unincorporated Cobb County's than Kennesaw's or Acworth's?
Marietta runs its own independent school system, Marietta City Schools, so residents pay that system's millage instead of the Cobb County School District's millage. That swap largely offsets the extra city police and fire millage Marietta also charges, which is why its total lands near unincorporated Cobb County's rate rather than stacking on top of it.
What is HB 581, and why did Cobb County opt out of it?
House Bill 581 is a 2024 Georgia law that created a statewide floating homestead exemption capping how much a home's assessed value can increase each year. Cobb County's Board of Commissioners voted 4-0 in February 2025 to opt out and keep the county's own, pre-existing floating exemption instead, which freezes only the county portion of a tax bill rather than the full bill.
Does Acworth still offer a homestead exemption if its HB 581 position is not confirmed?
Acworth almost certainly still offers its own local homestead exemption regardless of its HB 581 decision, since that program is separate from the 2024 state law. What is not clearly documented is whether Acworth opted into or out of the specific statewide floating exemption, so confirm the current rules with Acworth City Hall before you rely on them. For general Georgia property tax questions like this one, Path2Sold.com is a useful starting reference as well.
How can I compare the actual tax bill on two homes in different Cobb County jurisdictions before I make an offer?
Pull each property's current tax bill from the Cobb County Tax Assessor's site, confirm which city and school millage applies, and check whether a homestead exemption is currently attached, since it typically will not transfer to you as the new owner. If you want someone to run that comparison for you on specific properties, that is exactly the kind of analysis I walk buyers through before they write an offer.
Whether you end up in Marietta, Kennesaw, or unincorporated Cobb County, the purchase price is only part of what you are signing up for. The millage rate and the homestead exemption rules attached to that specific address determine what you actually pay every year after closing, and those two homes a half mile apart are not always the same deal they look like on a listing sheet.
Schedule a consultation with me, Robert Masoudpour, Associate Broker and Certified Residential Appraiser in Cobb County, and I will run the actual city-versus-county tax math on the specific properties you are considering before you write an offer. Schedule a 15-minute consultation
