AssessCheck

The Maryland Triennial Cycle and the Three-Year Phase-In

Every state on this site reassesses on a cycle. Maryland’s is unusual in two ways: the cycle is run from the state, not the county, and an increase it produces does not reach your taxable assessment all at once — it is phased in over three years by statute.

One-third of the county, every year

Since 1980, Maryland has divided each county (and Baltimore City) into three reassessment regions. SDAT reviews one region per year, so every property is revalued once every three years. The review is a full appraisal: SDAT’s assessors consider recent sales, property characteristics, and neighborhood trends, and they value the property at 100% of market value — the standard every Maryland assessment has used since 2001.

This is different from the "market arrives in a rush" pattern of a six- or eight-year revaluation state like Ohio or North Carolina. In Maryland, no property goes more than three years without a review — but each individual review sees three years of market movement at once, which is precisely why the phase-in exists.

The phase-in: a $30,000 example, straight from the state

The Maryland State Archives’ official description of SDAT uses its own worked example, and it is worth reproducing because it is the arithmetic owners most often misread:

  1. Old value: $200,000 (the phased-in value currently on the books).
  2. New value: $230,000 — a $30,000 increase found by the triennial review.
  3. Year 1: taxable assessment becomes $210,000 — the old value plus one-third of the increase.
  4. Year 2: $220,000. Year 3: $230,000 — the full new value.

What this tells you: if your notice shows a substantially higher value than your current assessment, your next bill reflects only about a third of the change. An owner who sees "$230,000" on the notice and sells the house expecting the tax to jump the full amount has misread the mechanism — the jump arrives in three steps.

What it does not tell you: the phase-in applies to increases only. A decrease takes full effect immediately. And the phase-in is on the taxable assessment, not the market value — SDAT’s records show the full new value from the first year.

How the phase-in interacts with the 10% cap

The phase-in and the homestead credit are two separate limits, and they stack:

In most years the phase-in already holds the increase to about a third of the market change, so the cap does little. But in a hot market — a region where values jumped 25% — the phased-in one-third (~8.3%) still leaves room for the cap to bind on some properties. The two mechanisms together are why a Maryland bill often moves far less than the market did.

The two non-reassessment years are not dead years

In the two years after your region’s review, no new assessment notice arrives — but your right to challenge the value does not pause. Maryland allows a petition for review in any of those years, filed with the Supervisor of Assessments within three years of the last final notice. If you believe the value set at your last review no longer reflects the market — a fire, a demolition, a market turn — the petition is the mechanism, and it is heard at the same first level as a regular appeal. See the appeal ladder for the deadlines.

What this page does not cover

The internal scheduling SDAT uses to sequence the three regions within each county, and any county’s specific reassessment calendar, are published by SDAT and your local office — not restated here. The values on your own Notice of Assessment control for your property.

Sources