Property Tax and the Territorial Tax System in Tumon, Guam

Real Property Tax: The Rates and the Assessed-Value History

Guam's real property tax is levied annually at 0.0972% of a parcel's assessed land value and 0.3889% of its assessed improvement value, according to the Guam Department of Revenue and Taxation's own published structure. Those headline rates look genuinely low next to most mainland US property tax rates, but the number that actually determines a bill is the percentage of appraised value the Legislature currently applies as 'assessed value' -- and that percentage has moved before. Guam's Office of Public Accountability documented the assessed-value rate shifting from 70% up to 90%, briefly to 100%, and back down to 90% as of 2016. That means the effective tax burden on an unchanged appraised value can rise or fall through legislative action alone, independent of the local real estate market -- a genuinely different dynamic than a fixed-millage mainland system, and one worth asking the Department of Revenue and Taxation about directly for the current rate before treating an old tax bill as a reliable estimate.

This page did not find a confirmed, current combined real property tax bill for a representative Tumon condo or resort-strip parcel -- condo unit assessments in a dense hotel-district corridor like Tumon can differ meaningfully from a standalone single-family parcel's assessment method, and this research did not independently verify how Guam's Department of Revenue and Taxation assesses individual condominium units within a larger resort structure. Confirm the specific assessment method and current bill for any Tumon unit directly with the Department before making an offer.

Guam's 'Mirror' Income Tax: A Federal Code, a Territorial Filing

Under federal law (48 U.S.C. § 1421i, and Internal Revenue Code Section 935), Guam is authorized to impose an income tax that is structurally identical to the federal Internal Revenue Code, with 'Guam' substituted everywhere the statute says 'United States.' In practice, this means Guam residents' income tax obligations follow the same brackets, deductions, and general mechanics as the federal system a mainland taxpayer would recognize, but the actual filing goes to the Guam Department of Revenue and Taxation, using forms that are close replicas of IRS forms, rather than to the IRS itself. This is a real, structural, and genuinely distinctive feature of Guam's tax relationship with the rest of the United States -- it is neither a state income tax system nor a foreign tax system, but a mirrored federal system administered entirely at the territorial level.

This page does not state current specific tax brackets, standard deduction amounts, or filing thresholds for Guam's mirror system, since those track federal changes over time and this research did not independently verify the currently applicable year's specific figures at a level this page is comfortable stating as settled fact. A tax professional licensed to handle Guam mirror-code filings -- not a generic mainland-only CPA -- should be consulted for actual filing obligations, since the mirror system carries real Guam-specific administrative quirks beyond simply using federal numbers.

Why the Mirror System Matters for a Buyer, Specifically

For a buyer relocating to Guam full-time, or a mainland resident buying a Tumon investment property while remaining a mainland taxpayer, the mirror system creates a genuinely important residency and sourcing question: which jurisdiction is owed tax on which income depends on Guam-specific residency and income-sourcing rules that differ from how a simple two-state move would work on the mainland. This page does not attempt to resolve individual sourcing questions -- they depend on a buyer's specific residency status, income sources, and whether the income is Guam-source or mainland-source -- and strongly recommends engaging a tax professional with specific Guam mirror-code experience before assuming a mainland tax strategy transfers cleanly.

The Business Privilege Tax Sits Alongside, Not Instead Of, Income Tax

Separate from both the real property tax and the mirror income tax, Guam levies a Business Privilege Tax (BPT) at 5% of gross receipts, effective since June 1, 2018 (up from 4%) -- this is the renamed successor to what Guam previously called its Gross Receipts Tax. Rental of real property is explicitly included in taxable gross income under Guam's business tax law, meaning any owner renting a Tumon property, whether short-term or long-term, faces BPT exposure on the rental income itself, in addition to any income tax owed on net profit under the mirror system. This site's Real Cost of Ownership and Vacation Rental Investment pages cover the BPT's practical impact on a rental pro forma in more depth.

What This Page Does Not State as Settled Fact

This page states Guam's real property tax rates and the assessed-value percentage history as sourced fact, and it states the existence and basic mechanics of the mirror income tax system and the 5% Business Privilege Tax as sourced fact. It does not state a specific current combined tax bill for any actual Tumon property, current federal-mirror income tax brackets or deduction thresholds for the applicable tax year, or how condominium unit assessments specifically are calculated within Tumon's resort-strip buildings, because none of those were independently confirmed at a level this page is comfortable stating as current, settled fact. It also does not offer tax-planning advice regarding residency status, income sourcing between Guam and the mainland, or Guam-specific tax credits or exemptions that may apply to a specific taxpayer's situation.

Who to Actually Ask

For current, binding numbers: the Guam Department of Revenue and Taxation (guamtax.com) is the authoritative source for both real property tax assessments and mirror income tax filing requirements. For a specific purchase, a Guam-licensed real estate attorney and a tax professional with direct Guam mirror-code filing experience are the right people to confirm exact current numbers and any residency-specific tax exposure before closing -- not a generic mainland tax preparer unfamiliar with the territorial system, and not an assumption carried over from a different US state's property tax experience.