How Are Property Taxes Calculated in Charleston in 2026?

South Carolina calculates property taxes by applying an assessment ratio to fair market value, four percent for an owner-occupied primary residence and six percent for a second home or rental, then applying the local millage rate. Millage is set annually by the county, city, and school district, so bills differ across Charleston, Berkeley, and Dorchester counties.

Property tax in South Carolina is not a single flat percentage of a home's price the way some other states calculate it. The process runs in two steps. First, the county assessor's office determines the property's fair market value and applies an assessment ratio to arrive at the assessed value: four percent of fair market value for a legal residence, meaning an owner-occupied primary home with the exemption applied for, and six percent for a second home, rental, or other non-owner-occupied residential property. That ratio alone means two identical houses can have very different tax bills if one is an owner's primary residence and the other is a rental or vacation property.

Second, that assessed value is multiplied by the millage rate, which is not one number but a stack of rates set separately by the county, the city or town, and the local school district, adjusted annually. Because Charleston, Berkeley, and Dorchester counties each set their own rates, and cities and towns within them add their own layer on top, the same assessed value produces a different final bill depending on exactly which town and school district the property sits in, Mount Pleasant versus Summerville versus North Charleston, for example. A legal residence also receives an exemption from the school operating portion of the millage, which is one reason confirming your legal residence status with the assessor matters.

Rates change from year to year and are not the same across every jurisdiction even within the tri-county area, so quoting a specific millage figure here would be wrong for most of the homes reading it. The reliable way to get your actual number is to contact the county assessor and auditor's office for the property's specific address, Charleston, Berkeley, or Dorchester, and ask for the current assessed value and millage. Most county offices post current-year rates and assessment appeal deadlines directly, and that is the only source worth trusting over an estimate.

For buyers, this matters at the offer stage: a property tax estimate should always be pulled for the exact address and exact use, primary residence or not, rather than assumed from a neighboring town's rate or a national estimate. For owners planning to sell, it is worth confirming your legal residence assessment is correctly applied before listing, since a rental-rate assessment that should have been corrected to legal residence status is a fixable expense a buyer will ask about.

Brian Beatty routinely points Charleston-area clients to the correct county assessor's office for their specific address rather than guessing, because the tri-county structure here makes a one-size answer unreliable.