Marietta, GA Property Tax Rate: Millage, Exemptions & Appeals

The combined property tax rate inside Marietta’s city limits is 31.122 mills for the 2025 tax year, which works out to about $31.12 for every $1,000 of assessed value.¹ Georgia assesses residential property at 40% of fair market value, so a home the county appraises at $400,000 has an assessed value of $160,000 and a gross tax bill of roughly $4,980 before any homestead exemptions are applied.

Where the 31.122 Mills Goes

Three separate taxing authorities set rates independently and then stack on your single bill. For 2025:

City of Marietta: 4.692 mills, split between 2.867 for general operations and 1.825 for bonded debt¹
Cobb County general fund: 8.46 mills, unchanged since 2018²
Marietta City Schools: 17.97 mills, held at that level for more than 25 years with only brief exceptions¹

Schools alone account for well over half of the total. One quirk works in Marietta residents’ favor: because the city runs its own fire department, properties inside city limits do not pay the 2.97-mill Cobb County fire district levy charged in unincorporated areas.¹ That is why Marietta’s 31.122-mill total ends up close to the 30.13 mills owed in unincorporated Cobb, even with the extra city levy added in.

Commercial properties in the Downtown Marietta Development Authority or the Gateway Marietta Community Improvement District pay small additional assessments on top of that.³ Residential homeowners generally pay the standard rate.

A Marietta mailing address does not necessarily mean the property sits inside the city. Addresses in 30060, 30062, and 30064 can fall in either incorporated Marietta or unincorporated Cobb County, and the taxing jurisdiction follows the parcel boundary, not the zip code. The millage rate and school district change with it.

Calculating Your Actual Bill

Georgia law fixes the assessed value of residential property at 40% of fair market value, which the Cobb County Board of Tax Assessors determines annually from comparable sales, property characteristics, and market conditions.⁴⁵ One mill equals $1 per $1,000 of assessed value.⁶

Working through a $400,000 home:

Fair market value: $400,000
Assessed value (40%): $160,000
Millage rate: 31.122
Gross tax: $160,000 × 0.031122 = $4,980

The quick formula: divide total millage by 1,000, multiply by assessed value. That gives you the gross figure. Most owner-occupants will see a lower number on their actual bill once homestead exemptions are applied.

Exemptions That Lower What You Actually Pay

Exemptions are the biggest lever a Marietta homeowner has, and plenty of eligible residents never file. Nothing is automatic, and every exemption requires that the home be your primary residence.

Basic Homestead

Two baseline exemptions apply to any owner-occupant regardless of age. The state standard homestead exemption reduces assessed value by $2,000 for county and school tax purposes.⁷ The Cobb County basic homestead exemption adds a $10,000 reduction in the county general and county school general categories.⁸ They stack.

Marietta’s Floating Homestead Exemption

Marietta offers a reassessment relief exemption, often called a floating homestead exemption, which protects city homeowners from tax increases driven by rising values. When a reassessment pushes your home’s value up, the exemption in the bond, cemetery, and city tax categories grows by the same amount, freezing taxable value in those categories at the level it was when you first qualified.⁹ It applies only to the city portion of the bill, not county or school.

Senior Exemptions

Marietta homeowners aged 62 or older qualify for a school tax exemption on the Marietta City Schools levy with no income requirement. You need to be the owner-occupant and at least 62 by January 1 of the tax year, and the exemption covers up to one acre of land.¹⁰ Since the schools levy is the largest single piece of your bill, this one matters most for qualifying seniors.

Additional state-level senior exemptions exist for homeowners 62 or older with combined household income of $10,000 or less (an additional school tax exemption) and for homeowners 65 or older at the same income threshold (a $4,000 reduction in state, county bond, and fire district taxes).⁷⁸ That income cap includes Social Security, so fewer people clear it than expect to.

Disabled Veterans

Qualifying disabled veterans can receive an exemption of up to $121,812 (the 2025 indexed amount) from county, municipal, and school property taxes, with the figure adjusted annually by the U.S. Secretary of Veterans Affairs.¹¹ The exemption passes to an unremarried surviving spouse or minor children who continue living in the home. Value above the exemption threshold remains taxable.

Filing

The standard filing deadline is April 1. Georgia recently extended the window, so you can now apply through the end of your 45-day period to appeal your annual notice of assessment, which typically arrives in early June.⁷ Miss the extended window and you lose the exemption for the full tax year with no retroactive fix. File through the Cobb County Tax Commissioner’s office with proof of ownership and residency; seniors should bring age documentation such as a driver’s license or birth certificate.⁹

When Bills Arrive and When Penalties Hit

Cobb County mails property tax bills by August 15, and payment is due October 15. A payment that arrives after October 15 triggers an immediate 5% penalty on the unpaid balance plus monthly interest until the account is paid.¹² Partial payments help, since the penalty only applies to whatever remains unpaid on the due date.¹³

You can pay online through the Cobb County Tax Commissioner’s website by credit card or electronic check (convenience fees apply), by mail, or at the secure drop box at the Cobb County West Park Government Center. If your mortgage escrows taxes, confirm your lender actually disbursed the payment before the due date. Federal rules require servicers to conduct an annual escrow analysis, but it runs on the lender’s schedule, not necessarily in time to catch a missed October payment.¹⁴

Accounts still unpaid after October 15 receive a 30-day late notice and eventually become subject to levy and tax sale.¹⁵ Georgia law gives the original owner at least 12 months after a tax sale to redeem the property before the purchaser can begin foreclosing the right of redemption.¹⁶

Appealing the Assessed Value

The millage rate is fixed, but the assessed value is not. If the Board of Tax Assessors values your home higher than you think it should, you have 45 days from the mailing date of your annual notice of assessment to file a notice of appeal.¹⁷ Notices typically mail in early June. Miss the window and the value stands for the year.

Residential appeals usually go to the county board of equalization, though private arbitration is available, and non-homestead properties valued above $500,000 can appeal to a hearing officer.¹⁷ The board must schedule a hearing within 15 days of receiving your notice. The strongest appeals bring recent comparable sales, an independent appraisal, interior and exterior photos showing actual condition, and documentation of any errors in the assessor’s records such as wrong square footage, lot size, or year built.

One provision gives homeowners real leverage: once an appeal is filed, the assessor’s office has 180 days to respond. If it fails to respond within that period, the value you asserted in your appeal becomes the official assessed value for the year.¹⁷

1
Cobb County Tax Commissioner. 2025 Millage Rates
2
Cobb County. Cobbs Board Approves FY26 Budget and 2025 Millage
3
City of Marietta. Property Tax
4
Justia Law. Georgia Code 48-5-7 – Assessment of Tangible Property
5
Georgia Department of Revenue. Property Tax Valuation
6
Georgia Department of Revenue. Property Tax Millage Rates
7
Georgia Department of Revenue. Property Tax Homestead Exemptions
8
Cobb County Tax Commissioner. Cobb County Homestead Exemptions
9
City of Marietta. Exemptions
10
City of Marietta. City of Marietta Residents Must File Homestead and School Tax Exemptions
11
Georgia Department of Veterans Service. Disabled Veteran Homestead Tax Exemption
12
Cobb County Tax Commissioner. Property Overview
13
Georgia Department of Revenue. Penalty and Interest Rates
14
Consumer Financial Protection Bureau. Escrow Accounts
15
Cobb County Tax Commissioner. Delinquent Taxes
16
Justia Law. Georgia Code 48-4-45 – Notice of Foreclosure of Right to Redeem
17
Justia Law. Georgia Code 48-5-311