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?
","findings":[{"body":"Zillow’s ZIP asking-rent index is $2,533, while the matched ZCTA’s ACS five-year median gross rent is $1,812. The 39.8% spread should be treated as a source-universe and timing difference: ZORI is a blended typical asking-rent index, whereas ACS covers occupied renter homes and selected utilities. Neither figure is a quoted rent for a specific available unit.","title":"Asking-rent index exceeds the occupied-renter survey measure"},{"body":"HUD’s local bedroom ladder produces modelled monthly estimates of $1,866 for a studio, $2,062 for one bedroom, $2,533 for two bedrooms, $3,392 for three bedrooms, and $3,904 for four bedrooms. They scale ZIP ZORI; HUD FMR/SAFMR itself is an administrative standard. These are not measured bedroom rents or listing-level comparables.","title":"Bedroom figures are HUD-scaled modelled estimates"},{"body":"The complete observed history shows 5.7% one-year growth, compared with 4.4% annualized over three years and 6.4% over five years. Annualized monthly-return variability was 3.3%, with a 2.1% maximum drawdown. That confirms an upward longer-run history, although the recent pace is below the five-year result. All measures are backward-looking, not forecasts.","title":"Recent rent growth continues, but does not exceed the five-year pace"},{"body":"Redfin’s direct rolling three-month ZIP resale observation recorded a $524,881 median sale price, down 3.7% year over year, along with 1.9 months of supply and a 100.98% average sale-to-list ratio. These are for-sale indicators, not rental data. The 5.79% annualized-rent-to-price screen is a cross-source ratio only; it does not quantify the economics of a particular property.","title":"Resale signals create a directional tension with asking rent"}],"risks":["The matched ZCTA and Zillow ZIP share the 04106 label, but a ZCTA is a statistical area rather than a USPS delivery ZIP, so address geography needs confirmation.","ACS rent, income, occupancy, vacancy, and burden figures are ZCTA five-year survey estimates. They may differ from live listings, newly signed leases, and the status of a particular building or household.","The HUD-scaled bedroom ladder preserves local bedroom proportions but is not measured rent. Unit size, utility treatment, lease terms, and current advertised availability remain separate checks for any address.","Redfin’s rolling resale metrics provide no rental transaction evidence, and the annualized-rent-to-price screen lacks expenses, financing, taxes, physical condition, and property-specific lease information needed for a property assessment."],"qa":[{"a":"Zillow ZORI represents a ZIP-level typical observed asking-rent index blended across rental types. ACS median gross rent is a five-year survey of occupied renter homes that includes selected utilities. Because they have different populations, timing, and construction, the $2,533 and $1,812 values should be compared as context rather than treated as competing quotes for one unit.","q":"Why are the Zillow and ACS rent figures different?"},{"a":"Each value is a modelled monthly ZIP estimate created by scaling the all-type Zillow index using local HUD bedroom proportions. It is not a measured studio or bedroom-specific asking-rent sample. HUD FMR/SAFMR is an administrative standard, so neither its value nor the scaled estimate establishes what any currently offered dwelling will rent for.","q":"What does the bedroom ladder measure?"},{"a":"The $101,320 figure simply annualizes the ZIP asking-rent index and divides it by 30%. It is a mathematical screening convention, not financial advice, a recommendation, or an applicant qualification rule. The ACS burden statistic instead reports the share of surveyed renter households spending at least that share, with no determination about any specific lease.","q":"Does the 30% required-income figure qualify an applicant?"},{"a":"History records a rent index that rose at different annualized rates over one, three, and five years, with measured variability and drawdown. Redfin records rolling three-month for-sale transactions and marketing signals. The rising rent index and lower resale median are a genuine directional tension, but they cannot be combined into a causal conclusion, a forecast, or property-level economics.","q":"How should the history and resale signals be read together?"}],"sources":[{"key":"apartment_list_time_on_market","name":"Apartment List Time on Market — listing liquidity","release":"Apartment List 2026-07","pulledAt":"2026-08-08","url":"https://www.apartmentlist.com/research/category/data-rent-estimates"},{"key":"apartment_list_vacancy","name":"Apartment List Vacancy Index — rental vacancy","release":"Apartment List 2026-07","pulledAt":"2026-08-08","url":"https://www.apartmentlist.com/research/apartment-list-vacancy-index-methodology"},{"key":"census_zcta_facts","name":"Census ACS five-year — ZCTA housing and income","release":"ACS 2024 5-year ZCTA","pulledAt":"2026-08-08","url":"https://api.census.gov/data/2024/acs/acs5.html"},{"key":"hud_zip","name":"HUD USPS crosswalk and Small Area FMRs — ZIP rent fallback","release":"ZIP-CBSA 2025Q4 + SAFMR FY2026","pulledAt":"2026-07-26","url":"https://www.huduser.gov/portal/datasets/usps_crosswalk.html"},{"key":"realtor_county","name":"Realtor.com Economic Research — county listing inventory","release":"county inventory 2026-06","pulledAt":"2026-07-28","url":"https://www.realtor.com/research/data/"},{"key":"redfin","name":"Redfin Data Center — inventory, days on market, and price cuts","release":"metro tracker through 2026-05-01","pulledAt":"2026-07-26","url":"https://www.redfin.com/news/data-center/"},{"key":"redfin_zip","name":"Redfin Data Center — ZIP resale activity and supply","release":"ZIP rolling 3 months through 2026-06-30; updated 2026-07-03","pulledAt":"2026-08-12","url":"https://www.redfin.com/news/data-center/"},{"key":"zillow_county","name":"Zillow ZHVI and ZORI — county values and rents","release":"county ZHVI/ZORI 2026-06","pulledAt":"2026-07-26","url":"https://www.zillow.com/research/data/"},{"key":"zillow_zori","name":"Zillow ZORI — metro market rents","release":"Metro_zori_uc_sfrcondomfr_sm_sa_month.csv","pulledAt":"2026-07-26","url":"https://www.zillow.com/research/data/"},{"key":"zillow_zori_city","name":"Zillow ZORI — city market rents","release":"zillow_zori_city.csv","pulledAt":"2026-07-29","url":"https://www.zillow.com/research/data/"},{"key":"zillow_zori_zip","name":"Zillow ZORI — ZIP market rents","release":"ZORI ZIP 2026-06","pulledAt":"2026-08-08","url":"https://www.zillow.com/research/data/"}],"history":[{"period":"2021-02-01","rent":1781.909564},{"period":"2021-03-01","rent":1766.32026},{"period":"2021-04-01","rent":1804.185796},{"period":"2021-05-01","rent":1799.041508},{"period":"2021-06-01","rent":1853.587461},{"period":"2021-07-01","rent":1891.769082},{"period":"2021-08-01","rent":1950.98271},{"period":"2021-09-01","rent":1965.337488},{"period":"2021-10-01","rent":1976.927406},{"period":"2021-11-01","rent":1987.197822},{"period":"2021-12-01","rent":2025.765333},{"period":"2022-01-01","rent":2051.126376},{"period":"2022-02-01","rent":2059.716373},{"period":"2022-03-01","rent":2077.133564},{"period":"2022-04-01","rent":2083.973147},{"period":"2022-05-01","rent":2147.675797},{"period":"2022-06-01","rent":2171.237073},{"period":"2022-07-01","rent":2206.720301},{"period":"2022-08-01","rent":2201.113802},{"period":"2022-09-01","rent":2209.754935},{"period":"2022-10-01","rent":2209.801561},{"period":"2022-11-01","rent":2184.26661},{"period":"2022-12-01","rent":2166.999578},{"period":"2023-01-01","rent":2172.01602},{"period":"2023-02-01","rent":2210.367138},{"period":"2023-03-01","rent":2220.635325},{"period":"2023-04-01","rent":2231.655369},{"period":"2023-05-01","rent":2217.224751},{"period":"2023-06-01","rent":2225.878648},{"period":"2023-07-01","rent":2235.873945},{"period":"2023-08-01","rent":2230.934615},{"period":"2023-09-01","rent":2214.631463},{"period":"2023-10-01","rent":2187.881061},{"period":"2023-11-01","rent":2204.259246},{"period":"2023-12-01","rent":2209.958425},{"period":"2024-01-01","rent":2246.775487},{"period":"2024-02-01","rent":2250.123444},{"period":"2024-03-01","rent":2259.040668},{"period":"2024-04-01","rent":2254.402942},{"period":"2024-05-01","rent":2249.05732},{"period":"2024-06-01","rent":2248.318413},{"period":"2024-07-01","rent":2237.104304},{"period":"2024-08-01","rent":2260.845012},{"period":"2024-09-01","rent":2289.815312},{"period":"2024-10-01","rent":2328.729251},{"period":"2024-11-01","rent":2345.799254},{"period":"2024-12-01","rent":2376.610107},{"period":"2025-01-01","rent":2379.53334},{"period":"2025-02-01","rent":2366.7942},{"period":"2025-03-01","rent":2362.512385},{"period":"2025-04-01","rent":2370.826204},{"period":"2025-05-01","rent":2389.626386},{"period":"2025-06-01","rent":2395.286382},{"period":"2025-07-01","rent":2410.48227},{"period":"2025-08-01","rent":2413.534235},{"period":"2025-09-01","rent":2417.414656},{"period":"2025-10-01","rent":2421.42264},{"period":"2025-11-01","rent":2426.791643},{"period":"2025-12-01","rent":2425.387399},{"period":"2026-01-01","rent":2426.094897},{"period":"2026-02-01","rent":2450.47469},{"period":"2026-03-01","rent":2472.103498},{"period":"2026-04-01","rent":2492.580863},{"period":"2026-05-01","rent":2509.605133},{"period":"2026-06-01","rent":2532.574074}],"historySummary":{"pointCount":65,"firstPeriod":"2021-02-01","latestPeriod":"2026-06-01","coverageMonths":65,"coverageRatio":1,"changes":{"1":{"years":1,"startPeriod":"2025-06-01","endPeriod":"2026-06-01","startRent":2395.286382,"endRent":2532.574074,"change":0.0573157736092369,"cagr":0.0573157736092369},"3":{"years":3,"startPeriod":"2023-06-01","endPeriod":"2026-06-01","startRent":2225.878648,"endRent":2532.574074,"change":0.13778622939555696,"cagr":0.04396728922443405},"5":{"years":5,"startPeriod":"2021-06-01","endPeriod":"2026-06-01","startRent":1853.587461,"endRent":2532.574074,"change":0.36630945519759317,"cagr":0.0644121291253732}},"maxDrawdown":-0.021464932809528214,"annualizedVolatility":0.03253917699132494,"consecutiveReturnCount":64}}