ZIP 21740 is both a Zillow ZIP market identifier and a Census ZCTA match; a ZCTA is a statistical area, not identical to a USPS delivery ZIP. The immediate decision question is how a current blended asking-rent signal should be read against household financial, stock, and bedroom-standard evidence that measures different things. In June 2026, Zillow’s ZORI is $1,317 per month, up 3.29% year over year. ZORI is a typical observed asking-rent index blended across rental types, so it establishes a ZIP-wide current benchmark rather than the price, utility package, or availability of a named property. The useful distinction here is between that current market signal and records that describe surveyed occupied homes or administrative program standards.
Stock evidence precedes any availability conclusion. In the ACS 2024 five-year matched ZCTA, the housing inventory totals 27,339 units: 25,276 are occupied and 2,063 are vacant, a 7.5% overall vacancy rate. The structure mix records 19,683 single-family units and 1,276 in the large-multifamily category. Vacancy composition separately lists 479 vacant-for-rent units, 298 vacant-for-sale units, and 231 seasonal units. These are area-level category counts, not a listing feed; the overall rate includes all vacancy reasons, and the for-rent count does not establish that a particular home is currently obtainable, at the ZIP benchmark, or suitable for a particular household.
The financial lens is also confined to the matched ZCTA survey universe. It records 11,290 renter-occupied homes, representing 44.7% of occupied homes, and median household income of $62,873. It records 5,325 renter households spending 30% or more of income on gross rent, an observed burden share of 47.2%. A cross-source arithmetic comparison annualizing the current ZIP index produces a 25.1% asking-rent-to-median-income comparison. A household would need $52,680 in annual income for the current index to equal 30% of income. That required-income screen is arithmetic, not advice, a claim about applicant qualification, or evidence of what any renter pays at a given unit.
Zillow, ACS, and HUD should be read as parallel, not merged, rent universes. The ACS median gross rent is $1,080; it is a five-year survey statistic for occupied renter homes and includes selected utilities. The current ZORI is 21.9% above that median, but the values should not be merged because Zillow measures a current typical observed asking-rent index across rental types. The local FY2026 HUD FMR/SAFMR two-bedroom standard is $1,233, and the ZIP ZORI is 6.8% higher. HUD FMR/SAFMR is an administrative bedroom-specific standard, not asking rent, so it is a calibration input and a separate program benchmark rather than a second market quote.
Bedroom interpretation uses HUD ratios rather than observations of ZIP listings. Scaling the ZIP ZORI through the local HUD ladder produces modelled monthly estimates of $908 for a studio, $1,026 for one bedroom, $1,317 for two bedrooms, $1,816 for three bedrooms, and $2,031 for four bedrooms. The underlying HUD standards are $850, $961, $1,233, $1,700, and $1,901 in the same bedroom order. The two-bedroom model matches the ZIP index by construction. These are modelled estimates, never measured bedroom rents: they translate a ZIP-wide blended index using the local HUD ladder and cannot show a unit’s actual layout, condition, utility treatment, or advertised rent.
Context values situate, but do not redefine, the ZIP signal. The City of Hagerstown context has a $1,442 rent measure and a 56.7% renter share; Washington County context has a $1,444 rent measure and a 33.2% renter share; and the Hagerstown-Martinsburg, MD-WV metro context has a $1,601 rent measure and a 24.4% rent-to-income measure. Each rent context measure is above the ZIP ZORI, while tenure and income-ratio comparisons refer to their named wider scopes. City, county, and metro statistics are contextual only; they cannot be pooled with ZIP/ZCTA results or used to assign the profile of an individual property.
Limits determine the final read: Zillow’s blended current index lacks lease-specific terms; ACS is a ZCTA survey rather than a USPS delivery geography; and HUD is an administrative standard. At the property level, check the actual advertised monthly base rent, bedroom count and floor plan, whether selected utilities are included, all recurring and nonrecurring charges, lease term, availability date, occupancy requirements, and whether the address is within the relevant ZIP delivery area. Confirm how the advertised rent is defined and which listed charges recur throughout the lease. Those checks identify the offered terms without assuming that a ZIP index, a survey burden, a vacancy count, or a modelled estimate describes that unit directly.