South Carolina Boat Property Tax Calculator: Ratios and 2027 Cut

The South Carolina boat property tax is calculated with a single formula: fair market value × assessment ratio × millage rate ÷ 1,000. For most recreational boats on 2026 tax bills, the assessment ratio is 10.5 percent of fair market value. A state law passed in the 2025–2026 session phases that ratio down toward an effective 6 percent between 2027 and 2029, so what you owe next year and the year after depends partly on when the bill is issued.

The Three Numbers You Need

Everything about your bill comes down to three inputs. Get each one and the math takes a minute.

Fair Market Value

The South Carolina Department of Revenue values boats and outboard motors using NADA marine appraisal guides, now published under the J.D. Power brand.¹ The value reflects your vessel’s condition as of the end of the prior year, and the Department of Revenue and Department of Natural Resources update personal property values annually, so your assessed value can move from year to year even if the boat hasn’t changed.² Boats and motors valued at $500 or less are exempt from property tax entirely.³

Assessment Ratio

State law assigns a percentage that determines how much of your boat’s market value is actually taxed. The percentage depends on how the vessel is classified. Most recreational boat owners use 10.5 percent.

Millage Rate

Millage is the tax rate per $1,000 of assessed value, and it varies by county and tax district. Two identical boats in different parts of the state can produce very different bills on millage alone. Your County Auditor can give you the exact rate for your address, and many counties publish current millage tables online.

Assessment Ratios by Boat Type

South Carolina Code Section 12-43-220 sets three ratios that matter for watercraft:

Recreational boats are assessed at 10.5 percent of fair market value. This covers the vast majority of privately owned vessels, including fishing boats, ski boats, pontoons, and personal watercraft like jet skis.⁴
Commercial fishing, tugboat, and pilot boats are assessed at 5 percent under the same statute.⁴
A boat that serves as a primary or secondary residence can qualify for a 6 percent ratio under Section 12-37-224. The vessel generally must have permanent built-in facilities for sleeping, cooking, and bathing. Owners apply through the County Auditor and usually provide documentation such as interior photographs or manufacturer specifications.

The residential classification can make a real difference. On a $100,000 boat, an assessed value of $6,000 instead of $10,500 saves hundreds of dollars a year depending on your millage. If your boat lacks a permanent galley, a dedicated head, or a fixed sleeping berth, it won’t qualify.

Working the Math

Take a recreational boat with a fair market value of $30,000 in a district with a millage rate of 250.

Assessed value: $30,000 × 10.5% = $3,150
Convert millage: 250 ÷ 1,000 = 0.250
Tax owed: $3,150 × 0.250 = $787.50

If that same boat qualified as a secondary residence at 6 percent, the assessed value drops to $1,800 and the tax comes to $450, a savings of $337.50 for the year. For a commercial fishing boat valued at $50,000 in the same district, 5 percent produces a $2,500 assessed value and a $625 bill. A district with a millage rate of 150 instead of 250 would cut any of these figures substantially.

The 2027 Watercraft Tax Cut

H.3858, enacted in the 2025–2026 session, phases in a property tax cut for watercraft starting January 1, 2027.⁵ The new law exempts 42.8571 percent of a watercraft’s fair market value from property tax, which effectively drops the assessment ratio from 10.5 percent to 6 percent once fully in effect. For 2026 tax bills, the old rules still apply.

The exemption phases in over three years:⁵

Tax year 2027: one-third of the exemption, roughly 14.29 percent of fair market value exempt
Tax year 2028: two-thirds of the exemption, roughly 28.57 percent exempt
Tax year 2029 and beyond: the full 42.8571 percent exemption, bringing the effective ratio to 6 percent

Boats already classified as a primary or secondary residence under Section 12-37-224 do not get an additional reduction, since they already sit at 6 percent.⁵ Some counties have already adopted a local ordinance under Section 12-37-220(B)(38)(b) that exempts 42.75 percent of watercraft value; that local option is repealed on January 1, 2030 once the state-level exemption is fully in place. If your county already offers the local version, your 2026 bill may already reflect a lower effective rate, so check with your County Auditor.

When the Bill Is Due

Watercraft property tax in South Carolina doesn’t follow a single statewide deadline. Since 2020, boat registrations renew annually, and the property tax bill is tied to your registration renewal month. Your renewal month is printed on the decal. For a newly titled boat, that month is set by your purchase date; buy in June, and the tax comes due each June from then on. The registration renewal fee is included on the property tax notice, so you handle both in one payment.⁶

If you owned the boat on December 31 preceding the current tax year, you owe the full year’s bill even if you sell it partway through.² If you dispose of the boat before paying, you still owe taxes from the date of purchase through the month you cancel the title and registration with SCDNR.⁷

Penalties for Paying Late

Under Section 12-45-180, delinquent bills pick up penalties in three rounds:⁸

3 percent if taxes are unpaid by January 16 or 30 days after the notice was mailed, whichever is later
An additional 7 percent if still unpaid by February 2
An additional 5 percent if still unpaid by March 17

Those three rounds add up to 15 percent on top of the original bill, and processing, posting, and advertising fees can be added as collection proceeds. There’s also a title problem: you cannot transfer the title on a watercraft with outstanding taxes, and knowingly selling a boat with unpaid taxes is a misdemeanor punishable by a fine up to $1,000 and up to 30 days of imprisonment.³

Appealing the Valuation

If the value assigned to your boat looks too high, file a valuation appeal with your County Auditor before the tax due date.⁷ Some counties take appeals online; others require paper or in-person filing. The auditor’s office generally responds within 30 days by mail. If the appeal succeeds before you pay, you’ll get an adjusted bill; if you already paid, expect a refund from the treasurer’s office in four to six weeks.

An approved appeal doesn’t stick. You have to file a new appeal each year if the valuation remains higher than you believe is accurate.⁹ Filing does not extend your payment deadline either, so if you want to avoid penalties while the appeal is pending, pay the bill as issued and take the refund if you win.

Military Exemption

Active-duty service members whose home of record is outside South Carolina are exempt from personal property taxes on boats, outboard motors, and personal watercraft like jet skis while stationed in the state. Apply through your County Auditor with supporting documentation. The exemption is good for one tax year, so you reapply each year you remain stationed here.¹⁰ Applications typically go in by mail, fax, email, or in person. If your home of record is South Carolina, this exemption does not apply.

Paying the Bill and Keeping Your Registration Current

Payment goes through the County Treasurer, not SCDNR. Most counties have an online portal that accepts credit cards with a processing fee, and mail-in checks or money orders are also accepted at the address on the notice.

The paid receipt matters beyond confirmation. If you buy a boat that’s already titled in South Carolina, you pay property taxes at the county tax office before SCDNR will transfer the title, and your registration application, titles, bill of sale, and other paperwork have to travel with the paid receipt. For out-of-state purchases or new boats from a dealer, SCDNR handles the initial titling and registration first, and your county bills you afterward. Boats documented with the U.S. Coast Guard rather than state-registered still owe personal property taxes to the county of residence if the county determines the vessel is taxable.⁶

1
South Carolina Department of Revenue. Casual Excise
2
County of Lexington. Personal Property Tax
3
Dorchester County, SC. Boats, Motors and Watercraft Property Tax
4
South Carolina Legislature. South Carolina Code 12-43-220
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South Carolina Legislature. 2025-2026 Bill 3858 – Taxation on Boats
6
SCDNR. Boating – Title and Register a Watercraft or Outboard Motor
7
Horry County SC.Gov. Boats and Watercraft
8
South Carolina Legislature. South Carolina Code Title 12 Chapter 45 – Section 12-45-180
9
Beaufort County Auditor. Looking to Appeal the Value of a Documented Vessel Tax Bill
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Oconee County, SC. Military Exemptions