The prominent tension in this ZIP is a split between rental and resale measures. Zillow ZORI, the ZIP’s typical observed asking-rent index blended across rental types, is $2,533 per month after a 5.7% year-over-year increase. At that same ZIP, Redfin’s resale measure reports a $524,881 median sold price, 3.7% below a year earlier. The contrast neither links the measures nor identifies an outcome for any property. It instead establishes the report’s central cross-universe question: how much confidence should a reader place in a rising current asking-rent index when the resale median moved the other way? Neither source supplies a matched rent-and-sale observation for the same dwelling.
Scope reconciliation is necessary before comparing those figures. The five-digit label 04106 is both a Zillow ZIP market identifier and a matched Census ZCTA; a ZCTA is a statistical area and is not identical to a USPS delivery ZIP. The ACS five-year median gross rent is $1,812, and it covers occupied renter homes while including selected utilities. The current Zillow index is 39.8% above that survey figure. It is not an alternate quote for a vacant apartment: Zillow measures typical observed asking rent across blended rental types, whereas ACS records a survey measure of occupied renters. Timing, inclusion rules, and statistical uncertainty therefore limit a point-for-point comparison. Each source serves a distinct descriptive purpose.
Bedroom planning adds a third evidence universe. HUD FMR/SAFMR is an administrative, bedroom-specific standard, not asking rent. Scaling ZIP ZORI with the local HUD ladder gives modelled monthly estimates of $1,866, $2,062, $2,533, $3,392, and $3,904 from studio through four bedrooms, respectively. These are modelled estimates, never measured bedroom rents, and simply distribute the all-type ZIP index in the ladder’s proportions. The HUD standard remains administrative; it does not convert the scaled figures into listing comparables or establish a particular unit’s current asking rent. It is an organizing benchmark, not a unit sample.
The affordability screen is arithmetic, not advice or an applicant qualification rule. At 30% of income, annualizing the current index produces a required income of $101,320. The matched ZCTA median household income is $86,188, making the asking-rent-to-income screen 35.3%. The contrast is a household-level benchmark, not a statement about any renter’s capacity to pay. In the ACS renter survey, 2,709 renter households reported spending at least that share on rent, a 53.2% burden share. That broad survey incidence cannot prove the burden, terms, or availability of a particular unit.
Housing stock and vacancy offer a separate matched-ZCTA backdrop. Of 12,860 housing units, 630 are vacant, yielding a 4.9% vacancy rate. The named structure categories include 7,506 single-family units and 2,230 units in large multifamily buildings. Vacancy is a status count, not a measure of rents, condition, or turnover at individual addresses. These counts describe stock and status across the statistical area; they do not document lease quality, timing, or availability at an address.
For wider geographic context only, the South Portland city context rent figure is $2,532.57, the Cumberland County context rent figure is $2,445, and the Portland-South Portland, ME metro context rent figure is $2,352. The ZIP reading is essentially aligned with the city context and higher than the county and metro contexts. Those wider areas are named comparisons, not substitutes for ZIP-level asking-rent evidence or the matched ZCTA’s occupied-renter survey. Their broader boundaries further limit address-level inference, and they should not be used as direct property rental comparables.
Looking backward, the ZIP ZORI history through the stated endpoint has 100% coverage across the observed series. Exact same-month change was 5.7% over one year, 4.4% annualized over three years, and 6.4% annualized over five years. The recent direction therefore confirms the longer rising path and exceeds the three-year pace, but it is slower than the five-year pace rather than a clean acceleration. Annualized monthly-return variability was 3.3%, and the maximum drawdown was 2.1%. The transparent national discovery ranks among history-eligible ZIPs are 320 for momentum, 1,987 for stability, and 683 for balance; lower rank is higher. Because the series has measured variability and drawdown, a single current rent snapshot merits measured confidence rather than precision. These are backward-looking measurements, not forecasts or investment recommendations.
Redfin’s direct rolling-three-month ZIP resale observation records 94 homes sold, a median 22 days on market, 58 homes of inventory, and 1.9 months of supply. Its average sale-to-list result is 100.98%, while 48.4% of sales were above list. These are all for-sale liquidity and pricing signals, not rental transactions. Annualized ZIP ZORI divided by the median sold price equals 5.79%, a cross-source screening ratio only and not a measure of property-level economics. The lower resale median alongside the rising asking-rent index and the stated resale supply challenges any simple shared directional reading. The source limits leave concrete property-level checks unresolved: can a live, comparable offering verify its exact address, current advertised rent, bedroom count, utility treatment, lease terms, condition, availability, and the dates behind any sales comparison?