Rent pressure is the clearest current tension in 94121, which is both Zillow’s ZIP market identifier and the matching Census ZCTA label. Zillow’s June 2026 ZIP ZORI, a typical observed asking-rent index blended across rental types, is $3,781 per month, up 17.2% from the same month a year earlier. Applying a 30% required-income screen to that index produces $151,240 a year, above the matched ZCTA’s ACS median household income of $133,358. That arithmetic screen places the index at 34.0% of that median; it is not advice, an applicant-qualification rule, or evidence of what any household pays. It does establish a useful separation between a current asking-rent measure and household-income context.
Comparison with the Census figure should not flatten that separation. The matched Census ZCTA’s ACS 2024 five-year survey places median gross rent at $2,363, and the current Zillow index equals 160.0% of that figure. ACS describes occupied renter homes over a five-year survey window and median gross rent includes selected utilities, whereas ZORI is a contemporaneous asking-rent index. A ZCTA is a statistical area used by Census and is not identical to a USPS delivery ZIP, even when it matches the label. The divergence therefore is source, timing, coverage, and definition context—not proof that like-for-like units changed by that amount.
Bedroom figures need an equally narrow reading. Scaling the ZIP ZORI by the local HUD ladder produces modelled monthly estimates of $2,607 for a studio, $3,123 for one bedroom, $3,781 for two, $4,830 for three, and $5,006 for four bedrooms. These are modelled estimates, not measured bedroom rents. The local HUD two-bedroom fair-market-rent standard is $3,604; HUD FMR/SAFMR is an administrative, bedroom-specific standard rather than an asking-rent observation. It supplies the scale of the model only, so the ladder cannot establish an advertised rent, utilities, condition, or unit mix for a particular listing. In particular, the matched two-bedroom figure reflects index scaling, not a direct two-bedroom rental sample.
Backward-looking history strengthens the case that the latest movement is unusually fast relative to the ZIP’s own longer path. The series has 100% coverage through its stated June endpoint. Exact same-month annualized changes were 17.2% over one year, 8.4% over three years, and 6.5% over five years. Thus, the recent direction confirms the longer rising path rather than breaking from it, but its pace accelerates markedly over the shortest window; none is a forecast or an investment recommendation. At 3.4%, annualized monthly-return variability indicates that individual monthly changes were not uniformly flat. Separately, the 11.1% maximum drawdown documents a materially larger historical retreat from a prior peak. Full coverage supports confidence that these are observed measures, yet acceleration and that drawdown limit the confidence deserved by a single current-rent snapshot. The transparent national discovery ranks among history-eligible ZIPs are 24 for momentum, 2,156 for stability, and 477 for balanced, where lower rank is higher.
Area comparisons position the ZIP between named wider benchmarks, but none replaces the ZIP series. San Francisco city, at city scope, has a rent context of $4,401; San Francisco County, at county scope, also has a rent context of $4,401; and the San Francisco-Oakland-Berkeley, CA metro, at metro scope, is $3,301. The ZIP’s current index sits below the named city and county contexts but above the named metro context. These are wider-geography context values, not local rental comps, and the county or metro figures do not alter the ACS ZCTA survey, HUD standard, or ZORI definition already used above. Scope is especially important when comparing an index with housing or income measures.
Survey housing composition adds a different constraint to the rent screen. The matched ZCTA estimates 19,777 housing units and a 7.9% vacancy rate; renters occupy 56.1% of occupied homes. Among renter households, 3,944 of 10,222, or 38.6%, are reported as rent burdened at 30% or more. The stock counts include 7,427 single-family units and 944 units in large multifamily structures. These ACS stock, tenure, vacancy, and burden aggregates describe the survey area, not real-time listings. They neither identify whether a vacancy is a rentable unit at a given price nor show that an individual renter or unit experiences the area-wide burden.
Resale, however, shows a brisk but separate for-sale signal. In Redfin’s direct rolling-three-month ZIP resale observation, median sold price was $2,257,490 and rose 19.1% year over year. The observation recorded 92 homes sold, a 14-day median marketing time, 113 active listings, an inventory count of 15 homes, and 0.5 months of supply. Average sale-to-list was 121.2%, and 79.9% of homes sold above list. Those are resale transactions and listings, not rental transactions or rental comps. The annualized ZORI divided by this median price is 2.01%, a cross-source screening ratio only—not a cap rate, net return, expected return, or property yield. Positive resale price movement directionally echoes the accelerating rent history, but the income screen challenges treating either market signal as a simple affordability conclusion.
Several boundaries remain decisive. ZORI does not supply property-specific bedroom observations, ACS does not update to the asking-rent month, HUD does not measure asking rent, and Redfin does not describe rental transactions. A property-level file would need the advertised rent and date, bedroom count, included utilities, lease term, concessions, current availability, and whether any cited sale is a genuinely comparable resale rather than merely a ZIP observation. It should also confirm the address’s geographic assignment and separate monthly rent from utilities. The published aggregates can frame those checks, but cannot resolve them or establish what a particular household qualifies for. Which verified unit-level terms remain after those source boundaries are applied?
","findings":[{"body":"Zillow’s June $3,781 asking-rent index increased 17.2% from the same month a year earlier. A 30% arithmetic screen converts that index to $151,240 of annual income, versus the matched ZCTA ACS median household income of $133,358. This is a comparison of a current asking-rent index and a survey income median, not a household qualification standard or a record of individual payments.","title":"Current asking rent outpaces the income screen"},{"body":"Through the June endpoint, ZORI’s same-month change is 17.2% over one year, compared with 8.4% across three years and 6.5% across five. That ordering identifies acceleration within a positive longer path. Complete coverage makes the history observable, but the variability measure of 3.4% and the prior 11.1% drawdown argue against assuming that today’s observation is a durable level.","title":"The rent path is accelerating but not smooth"},{"body":"ACS reports a five-year median gross rent for occupied renter homes, with selected utilities included, while ZORI captures a typical asking-rent index. Their numerical difference cannot be converted into a listing premium without unit-level matching. The ZCTA is a statistical Census area rather than a USPS delivery ZIP, adding a geographic boundary limit to the timing and definition differences.","title":"ACS and ZORI answer different rent questions"},{"body":"Redfin’s rolling three-month observation gives direct ZIP for-sale evidence, including fast marketing, limited supply, above-list outcomes, and a higher median sold price. It is not a rental sample. The 2.01% annualized ZORI-to-price calculation can organize a cross-source screen, but it is not a cap rate, property yield, net return, or forecast.","title":"Resale strength is a separate market signal"}],"risks":["The ZCTA’s matching label does not make it a USPS delivery geography, and the ACS five-year survey can differ from the ZIP asking-rent index in boundaries, timing, unit coverage, and utility treatment.","HUD standards and ZORI-scaled bedroom figures are not observed listings; actual bedroom rents may differ with unit condition, lease terms, included utilities, concessions, and availability that the packet does not identify.","History records prior index movement, including a historical drawdown, rather than future rent paths; complete coverage reduces missing-data concern but does not remove snapshot, revision, or definition risk.","Redfin reports a rolling ZIP resale sample, not rental transactions or property operating results. Its price signals and rent-price screening ratio cannot establish comparable sales, unit economics, or outcomes for a specific property."],"qa":[{"a":"ZORI is a typical current observed asking-rent index blended across rental types. ACS median gross rent is a five-year survey statistic for occupied renter homes and includes selected utilities. Because the matching ZCTA is statistical rather than a USPS delivery ZIP, the two results differ in geography, timing, population, and definition.","q":"Why can ZORI exceed ACS gross rent?"},{"a":"Each bedroom figure is a modelled estimate generated by scaling ZIP ZORI with the local HUD ladder. HUD FMR/SAFMR is administrative and bedroom specific, not observed asking rent. The results therefore do not verify the advertised rent, included utilities, physical condition, or lease terms of an individual unit.","q":"Are the bedroom figures observed rents?"},{"a":"The history measures prior index behavior through the endpoint. The shorter-horizon increase is faster than the longer-horizon changes, while monthly-return variability and a past drawdown show that the path was not perfectly smooth. Complete coverage supports observation quality, but none of these backward-looking measures predicts future rents.","q":"Does accelerating history forecast future rent growth?"},{"a":"Redfin’s percentage comes from annualizing ZIP ZORI and dividing by the ZIP median sold price observed in a rolling resale period. It crosses rental and for-sale sources solely as a screen. It excludes operating expenses, financing, taxes, property condition, and actual lease terms, so it cannot be labeled a yield or return.","q":"What does the ZORI-to-price screen measure?"}],"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":"2020-01-01","rent":2978.260041},{"period":"2020-02-01","rent":2973.104382},{"period":"2020-03-01","rent":3052.40061},{"period":"2020-04-01","rent":3027.794688},{"period":"2020-05-01","rent":3000.576108},{"period":"2020-06-01","rent":2949.232704},{"period":"2020-07-01","rent":2903.617308},{"period":"2020-08-01","rent":2876.922095},{"period":"2020-09-01","rent":2836.448848},{"period":"2020-10-01","rent":2809.008667},{"period":"2020-11-01","rent":2750.130246},{"period":"2020-12-01","rent":2714.089366},{"period":"2021-01-01","rent":2719.188106},{"period":"2021-02-01","rent":2732.349669},{"period":"2021-03-01","rent":2736.960257},{"period":"2021-04-01","rent":2728.480145},{"period":"2021-05-01","rent":2749.268174},{"period":"2021-06-01","rent":2758.883688},{"period":"2021-07-01","rent":2783.141227},{"period":"2021-08-01","rent":2791.831111},{"period":"2021-09-01","rent":2817.870338},{"period":"2021-10-01","rent":2836.225813},{"period":"2021-11-01","rent":2872.555138},{"period":"2021-12-01","rent":2861.775276},{"period":"2022-01-01","rent":2830.587837},{"period":"2022-02-01","rent":2867.197899},{"period":"2022-03-01","rent":2865.03894},{"period":"2022-04-01","rent":2914.748271},{"period":"2022-05-01","rent":2881.867131},{"period":"2022-06-01","rent":2926.028165},{"period":"2022-07-01","rent":2931.266241},{"period":"2022-08-01","rent":2940.755126},{"period":"2022-09-01","rent":2922.107505},{"period":"2022-10-01","rent":2933.82609},{"period":"2022-11-01","rent":2925.195922},{"period":"2022-12-01","rent":2975.533333},{"period":"2023-01-01","rent":2989.712559},{"period":"2023-02-01","rent":2984.712068},{"period":"2023-03-01","rent":2976.272008},{"period":"2023-04-01","rent":2958.732151},{"period":"2023-05-01","rent":2979.133155},{"period":"2023-06-01","rent":2966.085121},{"period":"2023-07-01","rent":2976.895979},{"period":"2023-08-01","rent":2973.482982},{"period":"2023-09-01","rent":2982.538191},{"period":"2023-10-01","rent":2976.360575},{"period":"2023-11-01","rent":3009.321698},{"period":"2023-12-01","rent":3031.423255},{"period":"2024-01-01","rent":3057.007437},{"period":"2024-02-01","rent":3023.554436},{"period":"2024-03-01","rent":3028.09809},{"period":"2024-04-01","rent":3009.254346},{"period":"2024-05-01","rent":3051.099608},{"period":"2024-06-01","rent":3045.803672},{"period":"2024-07-01","rent":3065.302592},{"period":"2024-08-01","rent":3054.294539},{"period":"2024-09-01","rent":3059.995985},{"period":"2024-10-01","rent":3085.175286},{"period":"2024-11-01","rent":3103.766643},{"period":"2024-12-01","rent":3110.540193},{"period":"2025-01-01","rent":3117.995234},{"period":"2025-02-01","rent":3125.166698},{"period":"2025-03-01","rent":3162.012902},{"period":"2025-04-01","rent":3209.425334},{"period":"2025-05-01","rent":3228.559208},{"period":"2025-06-01","rent":3224.673902},{"period":"2025-07-01","rent":3239.470269},{"period":"2025-08-01","rent":3288.454631},{"period":"2025-09-01","rent":3327.241706},{"period":"2025-10-01","rent":3356.548107},{"period":"2025-11-01","rent":3379.12954},{"period":"2025-12-01","rent":3410.581606},{"period":"2026-01-01","rent":3453.088814},{"period":"2026-02-01","rent":3534.20047},{"period":"2026-03-01","rent":3578.215519},{"period":"2026-04-01","rent":3632.551996},{"period":"2026-05-01","rent":3677.638191},{"period":"2026-06-01","rent":3780.544974}],"historySummary":{"pointCount":78,"firstPeriod":"2020-01-01","latestPeriod":"2026-06-01","coverageMonths":78,"coverageRatio":1,"changes":{"1":{"years":1,"startPeriod":"2025-06-01","endPeriod":"2026-06-01","startRent":3224.673902,"endRent":3780.544974,"change":0.1723805534740237,"cagr":0.1723805534740237},"3":{"years":3,"startPeriod":"2023-06-01","endPeriod":"2026-06-01","startRent":2966.085121,"endRent":3780.544974,"change":0.2745908562210815,"cagr":0.08423544181168463},"5":{"years":5,"startPeriod":"2021-06-01","endPeriod":"2026-06-01","startRent":2758.883688,"endRent":3780.544974,"change":0.3703169113086582,"cagr":0.06503579299480222}},"maxDrawdown":-0.11083448315783162,"annualizedVolatility":0.034223547431877284,"consecutiveReturnCount":77}}