Retiring in South Dakota: nothing on the state side, so the property bill and the federal return are the work

Social Security, pensions, IRA and 401(k) withdrawals, Roth conversions, military and government retirement pay, interest, dividends and capital gains: South Dakota taxes none of it, because the state has no individual income tax of any kind. There is no return on which to report retirement income and no credit or exclusion to claim, since there is nothing to exclude it from. The two places a South Dakota retiree’s income still matters are the federal return, which taxes all of it exactly as it would anywhere, and the county treasurer’s office, where the income limits on the over-65 assessment freeze and the senior refund are set low enough that a large IRA withdrawal in the wrong year can cost a homeowner that year’s relief.

The practical consequence is that a retiree who moves here from a state with an income tax does not get a simpler federal return. The 1040 is the same. What goes away is the second return, and with it the state withholding on the pension, the state estimated payments and the state-level retirement exclusions that may have mattered. What arrives is a set of property tax applications, each with an April or July deadline, and each with an income test that counts Social Security.

What South Dakota does not tax

The 2025 federal law’s $6,000-per-person senior deduction for 2025 through 2028 is a federal deduction; it has no South Dakota counterpart and needs none.

The federal return is the whole return

A South Dakota retiree files Form 1040 and stops. The paperwork that follows a retiree from another state does not know this. Pension administrators and IRA custodians withhold state tax for the state on file, and a custodian that has a Minnesota or Iowa address in its system will keep withholding for that state after a move to Sioux Falls until told otherwise. The fix is a new Form W-4P for periodic pension payments and Form W-4R for one-time withdrawals, with the state election set to none. Old-state tax withheld after the move comes back only on that state’s part-year return.

Federal withholding becomes the only withholding, and it is easy to let lapse. A household living on Social Security, an IRA and a brokerage account owes federal estimated payments when the balance after withholding will exceed $1,000; the safe harbors are 100% of last year’s tax, 90% of this year’s, or 110% of last year’s for higher incomes. The simplest South Dakota fix is withholding on the RMD: tax withheld from a December IRA withdrawal is treated as paid evenly through the year. The mechanics are in Estimated payments.

On Schedule A, the state and local tax deduction is property tax plus sales tax, since there is no state income tax to deduct. The sales tax figure comes from the IRS optional tables for the household’s income, size and local rate, plus the actual tax on a vehicle or other large purchase (verify treatment of the 4% motor vehicle excise tax). For most retirees the total is well under the 2026 standard deduction of $32,200 joint or $16,100 single, plus the additional amount for age 65 and the senior deduction, so most take the standard deduction and the property tax saves nothing on the federal return. That is worth knowing before paying a property tax bill early to “get the deduction.”

The federal items that still bite

Taxation of Social Security. Up to 85% of benefits are taxable federally when provisional income, which is adjusted gross income plus tax-exempt interest plus half of Social Security, exceeds $34,000 single or $44,000 joint; 50% above $25,000 and $32,000. Those thresholds have not been indexed since they were set, and the 2025 law did not change them; it added the senior deduction instead. A South Dakota retiree gets no state relief from this because there was never a state tax to relieve. See How Social Security is taxed.

IRMAA. Medicare Part B and Part D premiums for 2028 are set from the 2026 return’s modified adjusted gross income, and the first surcharge begins at $109,000 single and $218,000 joint for 2026 premiums. A large Roth conversion, a capital gain on a farm sale, or an inherited IRA distribution in 2026 can push a couple into a higher premium bracket for all of 2028. The address does not matter; the income does. See IRMAA.

Roth conversions. With no state tax, a conversion in South Dakota costs the federal tax alone, which makes converting in a low-income year between retirement and age 73 cheaper here than in a taxing state. The two cautions are IRMAA, above, and the property tax programs, below: a conversion raises federal AGI, and federal AGI plus Social Security is the income the county counts for the assessment freeze. A retiree near the freeze limit should size the conversion with the limit in mind, or convert in a year the freeze is not needed.

What South Dakota gives seniors instead

The age breaks are on the property tax bill, administered by the county treasurer and the Department of Revenue, and each one has to be applied for. In the order a homeowner is likely to meet them:

At any age: the owner-occupied classification. One application, by March 15, with the county director of equalization. It taxes the home at the owner-occupied school general fund levy, $2.518 per $1,000 of taxable value for taxes payable in 2026 and $0.669 for 2027, instead of $5.211 and $4.867. It is the most valuable item on this list, and it is not age-tested. A retiree who bought a South Dakota home and never filed it is paying the rental rate.

At 65, or on disability: the assessment freeze. The home’s full and true value stops rising for tax purposes while the owner qualifies, so the market can move and the taxable value does not. For 2026 the limits are household income under $56,595 for a one-person household or $66,885 for a household of two or more, and a home worth less than $514,500 (unless already on the program); the limits are indexed each January 1 and the 2027 figures are to come. Income is federal adjusted gross income plus any other income, including Social Security payments. The owner must have owned an owner-occupied single-family home and been a South Dakota resident for five years (unless on the freeze last year) and lived in the house at least 200 days of the prior year. Apply every year by April 1 with the county treasurer, on form PT 38.

At 65, or on disability, with low income: the Sales and Property Tax Refund. For 2025 taxes, claimed between May 1 and July 1, 2026, the income limit was $17,215 for a person living alone and $23,265 for a household. The applicant must have been a South Dakota resident all of the prior year and 65 by January 1 of that year, or disabled. The refund returns a share of the sales tax paid, or for a homeowner a share of the property tax, on a sliding scale by income (verify current schedule; the property tax refund has run up to 35% single and 55% household). It is filed with the Department of Revenue’s Tax Refund Office in Pierre, not the county, and a renter can claim the sales tax portion. The 2027 limits are to come.

At 70: the homestead deferral. A homeowner 70 or older, or a surviving spouse, with income and residency under the program’s limits (the Department’s 2025 presentation showed income under $17,949 single and $22,436 household (verify 2026 figures)), can defer the property tax entirely. The tax is not forgiven: it accrues as a lien, with interest at 4% (verify), and is paid when the home is sold or transferred. A participant cannot also take the Sales and Property Tax Refund. Apply by April 1 with the county treasurer, form PT 38C.

The disabled veteran exemption, the paraplegic exemptions and the municipal reduction that only Rapid City has adopted are covered, with the deadlines and the forms, in Property tax relief in South Dakota.