Data Sources
Every number used in HomeCostClarity tools comes from a named public source. Most data is updated automatically - the timestamps below show when each dataset was last refreshed.
State averages are used where county or ZIP-level data is unavailable. For the best results, enter your ZIP code in any tool that supports it - this unlocks county-level property tax rates, MSA-level appreciation data, risk-adjusted insurance estimates, and local utility cost tiers.
Mortgage and Lending
30-year fixed mortgage rate
Source: Freddie Mac Primary Mortgage Market Survey via FRED
Updated: weekly
Last refreshed: 2026-07-05
Fallback used: no
Next scheduled refresh: Every Monday 6am UTC
Updated weekly. The rate shown across all tools is the Freddie Mac Primary Mortgage Market Survey rate, which is the most widely cited benchmark for US residential mortgages.
Uses the most granular local source currently available in HomeCostClarity; falls back gracefully when live refresh is unavailable.
Conforming loan limits by county
Source: FHFA Annual Conforming Loan Limit Announcement
Updated: annual
Last refreshed: 2026-07-05
Fallback used: no
Next scheduled refresh: First Monday of December 9am UTC (FHFA publishes each November)
Updated annually each December. Determines whether a loan is conforming or jumbo for each specific county.
Uses the most granular local source currently available in HomeCostClarity; falls back gracefully when live refresh is unavailable.
Home Prices and Market Data
County median home prices
Source: Zillow Research - Zillow Home Value Index (ZHVI) by County
Updated: monthly
Last refreshed: 2026-07-05
Fallback used: no
Next scheduled refresh: First Monday of each month 7am UTC
Updated monthly. Zillow Home Value Index (ZHVI) for the median-priced home tier by county.
Uses the most granular local source currently available in HomeCostClarity; falls back gracefully when live refresh is unavailable.
Home price appreciation by state
Source: FHFA House Price Index - All-Transactions by State
Updated: quarterly
Last refreshed: 2026-07-05
Fallback used: no
Next scheduled refresh: First Monday of March, June, September, December 8am UTC
Updated quarterly. FHFA All-Transactions House Price Index - state level.
Uses the most granular local source currently available in HomeCostClarity; falls back gracefully when live refresh is unavailable.
Home price appreciation by metro area (MSA)
Source: FHFA House Price Index - All-Transactions by MSA/CBSA
Updated: quarterly
Last refreshed: 2026-07-05
Fallback used: no
Next scheduled refresh: First Monday of March, June, September, December 8am UTC
Updated quarterly. FHFA All-Transactions House Price Index - Metropolitan Statistical Area level. More precise than state averages for buyers in major metros.
Uses the most granular local source currently available in HomeCostClarity; falls back gracefully when live refresh is unavailable.
Normalized FHFA HPI appreciation assumptions
Source: Federal Housing Finance Agency House Price Index
Updated: quarterly
Last refreshed: 2026-07-06
Fallback used: no
Next scheduled refresh: First Monday of March, June, September, December 8am UTC
Used by planning calculators for local appreciation assumptions. HomeCostClarity tries metro first, then state, then national fallback. FHFA HPI is a weighted repeat-sales index of single-family home price changes.
Normalized FHFA HPI appreciation assumptions; falls back from ZIP/county/metro to state to national when local data is unavailable.
Property Taxes
Property tax rates by state
Source: Tax Foundation / Lincoln Institute of Land Policy
Updated: annual
Last refreshed: 2026-07-05
Fallback used: no
Next scheduled refresh: Manual - updated each January when Tax Foundation publishes
Updated annually. Effective tax rates - actual taxes paid as a percentage of home value - are more meaningful than nominal statutory rates.
Uses checked-in fallback data when live refresh is unavailable; verify important decisions with official local sources.
Property tax rates by county
Source: Tax Foundation / Lincoln Institute of Land Policy county data
Updated: annual
Last refreshed: 2026-07-05
Fallback used: no
Next scheduled refresh: Manual - updated each January
Updated annually. County-level effective rates for major US counties, covering approximately 90% of the US population.
Uses the most granular local source currently available in HomeCostClarity; falls back gracefully when live refresh is unavailable.
Insurance
Homeowners insurance premiums by state
Source: National Association of Insurance Commissioners (NAIC)
Updated: annual
Last refreshed: 2026-07-05
Fallback used: no
Next scheduled refresh: Manual - updated each spring when NAIC publishes
Updated annually. Average annual premium for a standard HO-3 homeowners policy.
Uses checked-in fallback data when live refresh is unavailable; verify important decisions with official local sources.
Natural hazard risk tiers by ZIP code
Source: FEMA National Risk Index
Updated: annual
Last refreshed: 2026-07-05
Fallback used: no
Next scheduled refresh: Manual - updated when FEMA publishes NRI updates
Updated annually. Risk tiers derived from FEMA National Risk Index composite hazard scores - covering flood, hurricane, tornado, wildfire, and other natural hazards.
Uses the most granular local source currently available in HomeCostClarity; falls back gracefully when live refresh is unavailable.
Utilities
Residential utility costs by state
Source: U.S. Energy Information Administration (EIA) - Residential Energy Consumption
Updated: monthly
Last refreshed: 2026-07-05
Fallback used: no
Next scheduled refresh: First Monday of each month 7am UTC
Updated monthly. Combines EIA electricity retail price data with EIA natural gas distribution survey data. Monthly electricity usage assumptions derived from EIA Residential Energy Consumption Survey (RECS).
Uses the most granular local source currently available in HomeCostClarity; falls back gracefully when live refresh is unavailable.
Utility cost tiers by ZIP code
Source: EIA Form 861 Electric Power Sales, Revenue and Energy Efficiency
Updated: annual
Last refreshed: 2026-07-05
Fallback used: no
Next scheduled refresh: Manual - updated when EIA publishes Form 861 annual data
Updated annually. Within-state utility cost tiers (below/average/above) based on EIA Form 861 electric utility service territory data.
Uses the most granular local source currently available in HomeCostClarity; falls back gracefully when live refresh is unavailable.
Closing Costs and Transfer Taxes
Average closing costs by state
Source: ClosingCorp Annual Closing Cost Study
Updated: annual
Last refreshed: 2026-07-05
Fallback used: no
Next scheduled refresh: Manual - updated each spring when ClosingCorp publishes
Updated annually. Average total closing costs as a percentage of purchase price, sourced from ClosingCorp annual closing cost study.
Uses checked-in fallback data when live refresh is unavailable; verify important decisions with official local sources.
County transfer tax rates - 15 high-variance states
Source: State revenue department statutory transfer tax rates
Updated: as-needed
Last refreshed: 2026-07-05
Fallback used: no
Next scheduled refresh: Manual - transfer tax rates change rarely, check annually
Updated as-needed. Statutory transfer tax rates for NY, PA, IL, MD, NJ, FL, TX, CA, MA, CT, DC, WA, CO, GA, OH - the states where county-level variation is most significant. Sourced from state revenue department websites.
Uses checked-in fallback data when live refresh is unavailable; verify important decisions with official local sources.
About State vs County vs ZIP-Level Data
State-level data is always available for all 50 states and DC. County-level data is available for counties covering approximately 90% of the US population. ZIP-level data - for insurance risk tiers, utility cost tiers, and location lookup - is available for most US ZIP codes. Where more granular data is unavailable, the tool falls back gracefully to the next level up. Every result clearly states which level of data was used.
State-level averages are used where county or ZIP-level data is not available. Actual costs vary significantly by specific city, county, neighborhood, and property. Always verify with local sources before making major housing decisions. HomeCostClarity is an educational tool - not financial, legal, or real estate advice.