Glossary

SDWIS (Safe Drinking Water Information System)

EPA's federal database of every community water system, its violations, lead-and-copper sampling, and treatment data.

Operated by the EPA, SDWIS aggregates compliance data reported by states under the Safe Drinking Water Act. Each community water system (CWS) appears with a unique PWSID identifier, its served population, and its violation history.

Updated quarterly. zipradar federates SDWIS at /topic/water-quality/ — showing the dominant CWS per ZIP, last 3 years of violations, and lead-copper results.

LCRR (Lead and Copper Rule Revisions)

EPA's 2024 update tightening lead-pipe inventories, sampling procedures, and trigger thresholds for action by water systems.

The Lead and Copper Rule Revisions require every water system to publish a service-line inventory by October 2024 identifying lead, galvanized-requiring-replacement, non-lead, and unknown lines.

The rule lowers the lead trigger level to 10 µg/L (down from 15 µg/L action level under the original rule) and mandates replacement of identified lead lines within 10 years.

PWSID (Public Water System ID)

Federal 9-character identifier assigned to every regulated US community water system (state code + 7-digit number).

Every public water system carries a PWSID. zipradar uses PWSID as the join key between SDWIS violation records and the geographic ZIPs each system serves.

Tier 1 violation (acute health-based)

Most-serious water-quality violation requiring 24-hour public notice — coliform/E. coli, nitrate exceedance, chlorine dioxide exceedance.

EPA classifies violations into Tier 1 (acute health, 24-hour public notice), Tier 2 (chronic health, 30-day notice), and Tier 3 (monitoring/reporting, annual notice). Tier 1 events appear with red flags on zipradar.

Service line inventory (SLI)

Mandatory LCRR catalog identifying every water service line as lead, galvanized-requiring-replacement, non-lead, or unknown.

Required for every US public water system as of October 2024. Updated annually. Used by lenders + insurers to assess remediation cost on home transactions.

FIRM (Flood Insurance Rate Map)

Official FEMA map showing flood-zone designations + base flood elevations for the 1% annual-chance flood for every US property.

FIRMs are the binding regulatory documents for NFIP flood insurance + lender flood-determination requirements. Updated by FEMA via map-revision projects, often in 5-10 year cycles.

BFE (Base Flood Elevation)

Elevation in feet above sea level that water reaches in a 1% annual-chance flood — the number that drives NFIP premium rating.

BFE applies in A, AE, AH, AO, V, VE flood zones. Lowest-floor elevation relative to BFE determines premium tier under NFIP Risk Rating 2.0.

LOMA (Letter of Map Amendment)

Official FEMA decision removing a structure from a Special Flood Hazard Area when natural ground elevation is at or above BFE.

Free to apply. Issued by FEMA after submission of an Elevation Certificate showing ground elevation. Successful LOMA = no mandatory NFIP coverage requirement on a federally-backed mortgage.

NFHL (National Flood Hazard Layer)

FEMA's authoritative GIS dataset combining all current FIRMs into a single nationwide flood-hazard layer.

Updated continuously. NFHL is the primary source zipradar federates for /topic/flood-zone/.

WHP (Wildfire Hazard Potential)

USDA Forest Service 5-step landscape-level wildfire-hazard score — Class 1 (very low) through Class 5 (very high).

Updated annually. Reflects landscape conditions (fuel load, climate, terrain), NOT property-specific factors like defensible space or roof material.

Defensible space

Maintained zone (typically 100 feet) around a structure where fuels are reduced to slow wildfire spread.

California PRC §4291 + similar laws in OR, CO, WA require Zone 0 (0-5 ft, hard surfaces only), Zone 1 (5-30 ft, lean clean green), Zone 2 (30-100 ft, reduced fuel).

ICC-500 (storm shelter standard)

International Code Council standard for tornado + hurricane safe rooms — wind speeds, debris loading, anchorage.

Pairs with FEMA P-361 design guidance. Required for FEMA Hazard Mitigation Grant Program rebates on home shelters in Plains states.

AQI (Air Quality Index)

EPA's 0-500 scale converting pollutant concentrations into a single index — Good (0-50) to Hazardous (301+).

Calculated for 5 pollutants: ozone, PM2.5, PM10, CO, NO2, SO2. The reported AQI is the maximum across pollutants. Live + historical via EPA AirNow.

PM2.5 (fine particulate matter)

Airborne particles 2.5 microns or smaller — small enough to enter lungs + bloodstream; primary wildfire-smoke health driver.

Sources: combustion (cars, power plants), wildfires, dust. EPA NAAQS 24-hr standard: 35 µg/m³ (revised 9 µg/m³ annual mean in 2024 update).

Ground-level ozone (O₃)

Secondary pollutant formed when nitrogen oxides + volatile organics react in sunlight — peaks summer afternoons.

Distinct from stratospheric ozone (good ozone). Ground-level ozone triggers asthma + reduced lung function. EPA standard: 70 ppb 8-hour.

UCR (Uniform Crime Reporting)

FBI program collecting standardized crime statistics from local agencies — historically Part I + II offenses; now NIBRS-based.

Originated 1930. As of 2021, UCR transitioned to NIBRS as the data backbone. Crime Data Explorer surfaces normalized per-capita rates.

NIBRS (National Incident-Based Reporting System)

Incident-level FBI crime database — 52 offense categories, victim/offender demographics, multi-offense per incident.

Replaces summary UCR. Provides far richer detail but adoption is uneven across local agencies; some report incomplete years.

CCD (Common Core of Data)

NCES annual census of every public elementary + secondary school in the US — enrollment, demographics, finance, locale.

Released annually. zipradar federates CCD at /topic/schools/ for school-by-ZIP coverage with locale + enrollment + Title I status.

SABS (School Attendance Boundary Survey)

NCES geographic dataset mapping the catchment boundary of every public elementary, middle, and high school in the US.

Used to determine which school a given residential address is zoned for. Updated biennially.

Title I (Elementary and Secondary Education Act)

Federal program providing supplemental funding to schools with high concentrations of low-income students.

Title I status appears in CCD records. Used as a proxy signal for student-population economic profile when zipradar surfaces school metadata.

EPA Radon Zone 1

EPA's highest-priority radon zone — counties with predicted average indoor radon ≥4 pCi/L (the action level).

Mapped in 1993 baseline; updated by states with newer surveys. Zone 1 counties span CO, IA, KS, KY, MN, MT, ND, NE, OH, PA, SD, WY + many others.

pCi/L (picocuries per liter)

Standard US unit for indoor radon concentration. EPA action level: 4 pCi/L; mitigation considered: 2-4 pCi/L.

Long-term test (90+ days) is the recommended method for real-estate decisions. Short-term tests (2-7 days) are screening only.

Millage rate (mill levy)

Property tax rate expressed as dollars of tax per $1,000 of assessed value. 1 mill = $1 per $1,000.

Total property tax = millage × (assessed value / 1,000). Set by overlapping taxing districts: school, county, municipal, special-service.

Homestead exemption

State-law tax break reducing property tax on a primary residence — varies wildly state-by-state.

Texas: $100k school-tax exemption. Florida: $50k + Save Our Homes 3% cap. California: Prop 13 acquisition-value caps. Most other states: $5-25k modest reductions.

Mello-Roos Community Facilities District

California special tax district funding new infrastructure (schools, roads) via additional property-tax assessment for 20-40 years.

Common in newer California subdivisions (post-1982). Adds $1,000-$5,000+ to annual property tax bills. Disclosed at sale via Mello-Roos statement.

Deed of trust

3-party security instrument (borrower, lender, trustee) used in lieu of mortgages in 30+ US states.

Trustee holds title until loan is paid; non-judicial foreclosure path. zipradar surfaces deed-recording activity at ZIP-rollup level (never individual owner names).

Title insurance

One-time-premium policy protecting against undiscovered defects in property title — owner's policy + lender's policy distinct.

Owner's policy: optional, protects equity, lasts as long as you own. Lender's policy: required by mortgage, covers loan balance only.

R1 zoning (single-family residential)

Most-restrictive residential zoning — single-family detached only, minimum lot size, minimum setbacks.

Variants: R1-6, R1-8, R1-10 etc. (number = minimum lot size in thousands of sq ft). Modern reform: many cities now permit ADUs in R1 by right.

ADU (Accessory Dwelling Unit)

Secondary independent dwelling on a single-family parcel — granny flat, in-law unit, garage conversion, detached cottage.

California SB 9 + AB 68 + similar Oregon, Washington, NY laws now mandate by-right ADU permits in most R1 zoning — fundamentally altering single-family character.

HOA deed restriction (CC&R)

Private covenant in subdivision deeds restricting use, appearance, or occupancy — often stricter than public zoning.

Conditions, Covenants, and Restrictions (CC&Rs) bind every owner. Run with the land. Can override more permissive zoning (e.g., HOA bans ADU even where city allows).

NSOPW (National Sex Offender Public Website)

DOJ-operated portal aggregating state + tribal + territorial sex-offender registries into a single search interface.

zipradar deep-links to NSOPW search results by ZIP — never caches personal records. Users complete searches on the official DOJ site.

YMYL (Your Money or Your Life)

Google's content category for pages where misinformation could harm a user's finances, health, or safety — held to higher quality standards.

Pages on real estate, health, and safety qualify. zipradar publishes only public-records data with primary-source citations + visible 'Last verified' dates per Google E-E-A-T guidance.

E-E-A-T (Experience, Expertise, Authoritativeness, Trust)

Google's quality framework for content evaluation — Experience added to EAT in December 2022.

Operationalized via author bylines, methodology pages, primary-source citations, contact information, transparent dates of last review.

IndexNow

Open protocol (Microsoft + Yandex) letting websites notify search engines of URL changes immediately, bypassing crawl-delay.

Supported by Bing, Yandex, Seznam, DuckDuckGo. zipradar pings IndexNow on every deploy via scripts/indexnow-ping.mjs.

Elevation Certificate (EC)

FEMA-mandated survey documenting a building's lowest-floor elevation relative to BFE — required for lowest NFIP premium tier.

Completed by a state-licensed land surveyor. Cost: $400-$900. Required by lenders for properties in A, AE, AH, V, VE flood zones to qualify for accurate Risk Rating 2.0 pricing.

NFIP (National Flood Insurance Program)

FEMA-administered federal flood-insurance program — only widely-available source of residential flood coverage in the US.

Standard homeowners policies exclude flood. NFIP fills the gap for participating communities (those that adopt FEMA floodplain-management standards). Coverage cap: $250k structure + $100k contents.

Risk Rating 2.0 (rolled out 2021-2023) replaced legacy zone-only pricing with parcel-level granular pricing.

WUI (Wildland-Urban Interface)

The geographic zone where homes meet undeveloped wildland vegetation — highest wildfire-property-loss risk.

Defined by USGS + USFS. Roughly 1/3 of US homes (44 million) sit in WUI. WUI residents face the brunt of recent California, Oregon, Colorado catastrophic-fire losses.

Insurance carriers increasingly use WUI classification + parcel-level WHP for underwriting decisions.

FRAP (CAL FIRE Fire and Resource Assessment Program)

California's authoritative wildfire-hazard-zone mapping program — feeds Fire Hazard Severity Zone (FHSZ) classifications.

FHSZ tiers: Moderate, High, Very High. Drives California PRC §4291 defensible-space requirements + insurance carrier underwriting.

NAEP (National Assessment of Educational Progress)

Federally-administered student assessment — the 'Nation's Report Card' — math + reading scores by grade + state.

Administered every 2 years to 4th + 8th graders nationally + selected high-schoolers. Different from state-administered tests; used for cross-state comparison.

Title III (English language acquisition)

ESEA federal funding stream for English-language-learner programs in K-12 schools.

Title III status appears in CCD records. Used as a signal of school's English-learner population concentration.

Easement

Recorded right of one party to use another's land for a specific purpose — utility, access, conservation, etc.

Common types: utility easements (power, water, sewer), access easements (driveway/road), conservation easements (preserve open space, often tax-deductible). Disclosed at title search.

Encumbrance

Any claim or restriction on a property's title that may diminish its value — liens, easements, deed restrictions, encroachments.

Title insurance protects against undisclosed encumbrances. Buyer review of preliminary title report (PTR) before close is critical.

Lien

Legal claim against property to secure debt — mortgage liens, mechanic's liens, tax liens, judgment liens.

Liens recorded in county records. Mortgage lien is the most common; mechanic's liens (unpaid contractors) often surprise sellers at closing. Senior liens paid first at sale.

As-of-right (zoning)

Land use permitted by zoning code without requiring a discretionary review, variance, or special exception.

If a use is as-of-right, the local building department issues a permit on application. Non-as-of-right uses require zoning-board review (variance, special permit, conditional use).

Variance (zoning)

Discretionary zoning-board approval relaxing a specific rule (setback, height, lot coverage) for a specific parcel.

Variance applications require demonstrating 'unnecessary hardship' or unique parcel conditions. Public hearing usually required. Granted variances are recorded against the deed.

Setback

Minimum distance a building must sit from a lot line — front, side, rear setbacks defined per zoning district.

Common R1 setbacks: 25 ft front, 5-10 ft side, 20 ft rear. Encroachments require variance. Setbacks shape neighborhood character + light/air access.

FHFA conforming loan limit

Annual maximum mortgage-loan amount eligible for purchase by Fannie Mae or Freddie Mac — varies by county.

2025 baseline: ~$766k single-family; high-cost-area limit ~$1.15M. Loans above are 'jumbo' — different rates + underwriting. The county limit influences home-price ceiling.

Post-FIRM (post-Flood-Insurance-Rate-Map)

Buildings constructed AFTER the community's first FIRM was issued — built to floodplain-compliant standards by code.

Post-FIRM properties get NFIP rates based on actual elevation difference from BFE. Pre-FIRM properties (older buildings) often get grandfathered rates that may be cheaper than flat-elevation pricing.

BDC (Broadband Data Collection)

FCC's 2022-onward replacement for Form 477 — collects ISP coverage data at the location level instead of census-block level.

Output is the National Broadband Map at broadbandmap.fcc.gov. Updated semi-annually. Public can challenge ISP-reported coverage via the BDC challenge process.

AFDC (Alternative Fuels Data Center)

DOE-operated authoritative directory of every public EV charger + alternative fuel station in the US.

Searchable map at afdc.energy.gov/stations. Filterable by connector type (J1772/CCS/CHAdeMO/Tesla NACS), charging level (L1/L2/DCFC), network, and access (24/7 vs limited).

Updated weekly via partnership with PlugShare + station operators.

Level 2 EV charging

240V EV charging — ~25-40 miles range/hour. Standard for home installation + most public chargers (workplaces, retail).

Hardware: ~$400-$900. Electrician install: ~$400-$2,500. Federal IRA Section 30C tax credit covers 30% up to $1,000 through 2032.

DCFC (DC Fast Charging) / Level 3

50-350 kW EV charging — 10-80% charge in 18-40 minutes. Highway corridors + paid stations only.

Tesla Supercharger, Electrify America, EVgo, ChargePoint Express are major networks. Connector: CCS for most non-Tesla; Tesla NACS becoming standard in 2026.

Walk Score

0-100 walkability index from Walk Score (Redfin) — measures distance to amenities + intersection density + block length.

90-100 Walker's Paradise. 70-89 Very Walkable. 50-69 Somewhat Walkable. 25-49 Car-Dependent. 0-24 Car-Dependent.

Doesn't account for hills, weather, sidewalk quality, or safety. Verify with on-foot visit.

Transit Score

0-100 index measuring distance to + frequency of public-transit lines (bus, light rail, heavy rail, ferry).

Frequency matters more than mere presence. City averages: NYC 84, SF 80, Boston 74, Chicago 65, DC 71, Seattle 60, LA 53.

NTNM (National Transportation Noise Map)

DOT/BTS map combining highway + rail + aviation noise into a 0-90+ dB color-coded nationwide layer.

Updated annually. Color thresholds: <50 dB residential-acceptable, 50-60 dB suburban-typical, 65-75 dB high (highway-adjacent), 75+ dB unacceptable for residential.

DNL (Day-Night Average Sound Level)

FAA + EPA standard for cumulative airport noise — 24-hour average dB with 10 dB nighttime penalty (10pm-7am weighted higher).

65 dB DNL is the FAA threshold for 'noise-impacted' residential property under Part 150.

NEM (Noise Exposure Map)

FAA-required Part 150 map showing 65 dB DNL contour around an airport — properties inside are formally noise-impacted.

Resale impact: properties inside 65 dB DNL contour sell 8-15% below comparable properties outside the contour.

Starlink (rural broadband fallback)

SpaceX low-earth-orbit satellite internet — 50-200+ Mbps with ~30-50ms latency, available in most US locations excluding heavy obstructions.

Hardware: ~$400-$600 dish. Service: ~$120/mo standard residential. Most-cited fallback for rural addresses with no fiber/cable/fixed-wireless option.

FEMA Map Service Center (MSC)

Authoritative FEMA portal for ordering parcel-level FIRM panels + flood-determination certificates + LOMA applications.

Free FIRMette downloads available. Letter of Map Amendment (LOMA) applications + Elevation Certificate uploads happen here.

IRA Section 30C (Alternative Fuel Refueling Property Credit)

Federal tax credit covering 30% of EV charger install cost (up to $1,000 residential) through 2032 in eligible census tracts.

Eligible tracts: low-income communities + non-urban areas (covers most US ZIPs not in dense metropolitan cores). Residential cap: $1,000. Commercial cap: $100,000.

CCA (Community Choice Aggregation)

Community-level electricity-sourcing program where local government negotiates renewable supply on behalf of residents.

Common in CA, NY, MA, IL, OH, NJ. Defaults customers into the program; opt-out preserves utility-default service. Often offers cleaner-mix or lower-cost rates than incumbent utility.

DOI (Department of Interior — public lands)

Federal department managing 480 million acres of public land via BLM, NPS, USFWS, BIA. Adjacent property values affected by access + grazing rights.

Properties bordering BLM land have public-access easements. National Park / monument adjacencies often boost values 10-25%. Tribal-trust land complications require disclosure.

ALTA Survey

Standardized boundary survey accepted by lenders + title insurers nationally — boundary lines, encroachments, utilities, easements per ALTA/NSPS table A.

Costs $400-$2,500 depending on parcel size + complexity. Required for commercial transactions; recommended for residential when title questions exist (boundary disputes, easement claims).

Cap rate (capitalization rate)

Investment-property valuation metric: net operating income ÷ purchase price. Lower cap rate = higher price relative to income.

Typical residential rentals: 4-8%. Class-A multifamily: 4-5%. Tertiary markets: 7-10%. Used to compare property investment yields independent of financing.

1031 exchange (like-kind exchange)

IRS provision allowing deferral of capital-gains tax when investment property is exchanged for another investment property within 180 days.

Strict rules: identify replacement within 45 days, close within 180 days, qualified intermediary required. Primary residences NOT eligible (separate Section 121 exclusion applies).

Section 121 (capital gains exclusion)

IRS exclusion: $250k single / $500k married of capital gains on sale of primary residence if owned + occupied 2 of last 5 years.

Doesn't roll over — use it or pay. Limited to once every 2 years. Reduces by partial-period if not full 2 years lived.

Schedule C (NFIP add-on coverage)

NFIP optional policy adding contents, basement, or building-code-upgrade coverage on top of standard policy.

Standard NFIP: $250k structure + $100k contents. Schedule C ICC adds up to $30k for code-required elevation/demolition after declared flood event. Often unused; ask for it.

Transformer capacity (electrical service)

Local utility's incoming transformer max load — limits how much electrical service a property can support without upgrade.

Old subdivisions often have 60-100 amp service; modern requirements (EV charging + heat pump + induction) need 200-400 amp + new transformer. Utility upgrades cost $5,000-$25,000+ if transformer needs replacement.

Septic system (on-site wastewater)

Self-contained wastewater treatment for properties without public sewer — typically tank + leach field + soil percolation.

Lifespan: 25-40 years. Replacement: $5,000-$25,000+ depending on soil conditions + system size. Inspection mandatory at sale in many states. Failure to maintain = environmental violation + costly remediation.

Perc test (percolation test)

Soil-permeability test required by health department before installing septic system or building on undeveloped land.

Measures rate water drains through soil. Failed perc = no septic = unbuildable in many counties. Cost: $200-$1,500. Always done before purchase of undeveloped lots.

ADA compliance (Americans with Disabilities Act)

Federal accessibility requirements for commercial properties + multi-family rentals — ramps, doorways, parking, restrooms.

Title III applies to public accommodations + commercial facilities. Multi-family rentals built post-1991 = FHAA accessibility requirements. Title II = state/local government buildings.

HVAC zoning

Multi-zone climate control allowing different temperatures in different parts of the home — 2-zone, 3-zone, 4-zone systems common.

Reduces energy cost 20-40% vs single-zone. Adds $1,500-$5,000 to install. Zone count is a real-estate listing claim worth verifying — false zones (one thermostat, multiple registers) common.

FHA Loan (Federal Housing Administration)

Federal-insured mortgage with 3.5% down for FICO 580+ and 10% down for FICO 500-579. Mortgage Insurance Premium (MIP) for life of loan unless 10%+ down.

2026 county loan limits: $498k (low-cost) to $1.15M (high-cost). HUD.gov has the lookup. FHA-approved appraiser required. Stricter property condition requirements than conventional.

VA Loan (Department of Veterans Affairs)

Federal-backed mortgage with 0% down for qualified veterans, active military, surviving spouses. NO mortgage insurance.

Funding fee: 1.4-3.6% (waived for disabled veterans). No income limit. Minimum Property Requirements (MPRs) include working heat, water, no peeling lead paint pre-1978. Can stack with state DPA.

USDA RD Loan (Rural Development)

Federal 0% down loan for properties in eligible rural areas with income capped at 115% of area median.

eligibility.sc.egov.usda.gov has address-level eligibility lookup. Many suburban areas surprisingly qualify. 1% upfront guarantee fee + 0.35% annual MIP equivalent.

MCC (Mortgage Credit Certificate)

Federal tax credit on mortgage interest paid — converts a portion of mortgage interest deduction into a dollar-for-dollar credit.

Issued by state housing finance agencies (HFAs). Typical: 20-30% credit rate on interest paid. Must be applied for at time of loan origination. Stacks with FHA/VA/USDA + state DPA.

Tax-deed state

State where county tax sales transfer the property DEED directly to highest bidder (vs. tax-lien states which sell only the lien).

~22 states are tax-deed: AK, AR, CA, CT, DE, ID, KS, ME, MA, MI, NV, NH, NM, NY (some counties), NC, OK, OR, RI, TX (mixed), UT, VA, WA. Buyer takes possession with redemption period 0-1 years typical.

Tax-lien state

State where county tax sales sell only the LIEN; investor earns interest on back-tax balance until owner redeems.

~28 states are tax-lien: AL, AZ, CO, FL, GA, IL, IN, IA, KY, LA, MD, MS, MO, MT, NE, NJ, ND, OH, SC, SD, TN, VT, WV, WI, WY. Interest rates 8-36% statutory. Foreclosure to deed allowed after 1-3 year redemption window if no payment.

Redemption period

Statutory window after a tax sale (or foreclosure) during which the original owner can pay back debt + interest to recover the property.

Tax-lien states: typically 1-3 years. Tax-deed states: typically 0-12 months (some none). IRS has 120-day federal redemption right on parcels with federal tax lien at time of sale.

WBGT (Wet Bulb Globe Temperature)

Heat-stress measurement combining air temp + humidity + solar radiation. Used by military + sports for outdoor-activity safety thresholds.

More accurate than Heat Index for outdoor work. OSHA + military thresholds: ≥85°F WBGT = caution; ≥90°F = high risk; ≥95°F = work-rest cycles required.

Heat pump

Reverse-cycle HVAC system that both heats AND cools — moves heat from outside to inside (or vice versa) instead of generating it.

2024 was first year heat-pump sales exceeded gas-furnace sales in US. IRA Section 25C tax credit covers 30% up to $2,000 for residential heat-pump installs. Cold-climate (CCHP) variants work efficiently to -15°F. Backup heat-strip recommended for severe-cold zones.

IRA Section 25C (Energy Efficient Home Improvement Credit)

Federal tax credit for energy-efficiency upgrades — 30% up to $1,200 annual cap on insulation/windows + $2,000 on heat pumps + $150 on home audit.

Through 2032. Stacks with state utility rebates. Upgrades include heat pumps, heat-pump water heaters, induction stoves, panel upgrades supporting electrification, biomass stoves. Form 5695 on tax return.

Certificate of Occupancy (CO)

City-issued document confirming a building has passed all final inspections and is legally occupiable.

Required after new construction + significant remodels + change-of-use (residential to commercial, etc.). Most jurisdictions issue per-unit. Lenders + insurers may require CO before closing. Permit pulled but no CO = work unfinished or failed inspection.

Structural engineer letter / report

Licensed structural engineer's professional opinion on a building's load-bearing systems — required for non-standard renovations + post-disaster + insurance disputes.

Cost: $400-$2,500 depending on scope. Required for: removed bearing walls (retrofit verification), foundation cracks of concern, post-fire/flood/earthquake sale, alterations affecting load path. Often requested by insurers before issuing/renewing policy on older homes.

WOTUS (Waters of the United States)

EPA + Army Corps of Engineers' definition of which water bodies fall under Clean Water Act jurisdiction — affects what counts as a regulated wetland on your parcel.

WOTUS scope has been redefined multiple times since 2015 (Obama → Trump → Biden → 2023 Sackett v. EPA Supreme Court ruling). Current rule (post-Sackett, May 2024): only wetlands with continuous surface connection to traditional navigable waters qualify. Isolated wetlands → no federal jurisdiction.

Why it matters for buyers: parcels with seasonal wet areas may or may not require a Section 404 permit before grading/filling. State wetland rules often broader than federal. Check your state environmental agency in addition to USACE.

CSA (Conservation Soil Assessment) / NRCS Soil Survey

USDA Natural Resources Conservation Service's free per-parcel soil-type map — critical for septic design, foundation type, agricultural use, and erosion risk.

Free via the NRCS Web Soil Survey (websoilsurvey.sc.egov.usda.gov). Returns: soil series name, drainage class, depth to bedrock, depth to water table, slope class, hydrologic group, prime farmland flag, and engineering ratings for foundations + septic.

Why it matters: a property in a 'severe' rating for 'dwellings without basements' often needs an engineered foundation. 'Severe' for septic = expensive alternative systems ($15-40k vs $5-10k conventional). Check before unconditional offer.

Tax abatement

Temporary partial or full property-tax reduction granted by a local government to incentivize development, renovation, or use — typically 5-20 years.

Common forms: PILOT (payment in lieu of taxes), 421-a (NYC residential), historic-rehab abatements, enterprise-zone abatements, brownfield-cleanup abatements. Buyer due-diligence: confirm remaining abatement years + reset trigger (sale often resets) + post-abatement tax estimate.

Hidden cost: abatement-end property-tax shock can be 3-5× the prior bill, breaking mortgage affordability assumptions. Always model the post-abatement carrying cost before purchase.

421-a / 421-g (NYC tax exemptions)

New York City residential tax-abatement programs that reduce property tax on qualifying new-construction (421-a) or commercial-to-residential conversion (421-g) for up to 35 years.

421-a closed to new applicants in 2022; existing certificates honored until expiration. Replacement: Affordable Neighborhoods for New Yorkers (ANNY) program, June 2024. 421-g (lower Manhattan) sunset for new applicants in 2006.

Why it matters: NYC condos and rentals with active 421-a often have artificially low monthly cost during the abatement; expiration triggers a 20-100% tax-bill jump. Check the NYC Department of Finance tax bill before offer; ask for the post-expiration estimate.

MLS 'coming soon' status

Listing status preceding 'active' on the local Multiple Listing Service — sellers expose to MLS members but defer photos/showings, typically 7-21 days.

Used to build buyer-list interest before going active. NAR rule change (2020 Clear Cooperation Policy): listings entered into the MLS must go 'active' within 1 business day of any public marketing.

For buyers: 'coming soon' inventory is visible to your agent's MLS feed before it hits Zillow/Redfin/Realtor.com — ask your agent to set up an MLS direct-feed alert. First-mover advantage matters in fast markets.

FEMA NFIP / IRMA / RiskRating 2.0

Federal flood-insurance program. Risk Rating 2.0 (Oct 2021+) priced policies on per-property risk (elevation, distance to water, rebuild cost) instead of FEMA flood zone alone.

Old policy: pricing driven by FEMA flood-zone designation (Zone A/AE/VE = expensive; Zone X = cheap). New policy: pricing on full risk profile, capped 18% increase/year. Some inland properties saw rates 2-4× higher than under old methodology.

Why it matters: a property in low-risk zone X can still carry a premium under RR2.0 if it sits at low elevation or near a stream. Always pull NFIP quote BEFORE offer; don't assume zone = price.

LOMR (Letter of Map Revision)

FEMA's formal revision of a flood map after a physical change (levee, channel modification, fill, or new survey data) that affects the BFE or zone designation.

Distinct from LOMA (Letter of Map Amendment): LOMA is for a single property already shown incorrectly; LOMR revises the FEMA Flood Insurance Rate Map (FIRM) itself for a defined area, often after engineering work like a new levee or channel widening.

Why it matters: a recently issued LOMR can change zone X to AE (or vice versa) for an entire neighborhood. Buyers in flood-prone metros should ask their agent whether any LOMR is pending or recently effective for the property's census tract.

FHFA House Price Index (HPI)

Federal Housing Finance Agency's quarterly + monthly index of US single-family home prices, calculated from millions of repeat sales + refinance transactions of mortgages backed by Fannie Mae/Freddie Mac.

Released quarterly (national + state + MSA) with monthly national updates. Most reliable price-trend dataset because it's repeat-sales-based (controls for property quality + size) and covers ~80% of US conforming-mortgage market.

Why it matters: when you read 'home prices up 5.2% YoY', most credible figures come from FHFA HPI or Case-Shiller. zipradar uses FHFA HPI as the state-level price-trend anchor referenced on /state/[state]/ pages.

EAB (Emerald Ash Borer) quarantine

USDA APHIS regulatory quarantine for the invasive beetle Agrilus planipennis. Counties under quarantine cannot move ash wood or nursery stock; affects firewood transport + landscape value.

First detected in Detroit area in 2002; now in 36+ states. APHIS lifted the federal quarantine in January 2021 but states maintain their own programs. EAB has killed an estimated 40+ million ash trees in North America.

Why it matters for buyers: parcels with mature ash trees in quarantine zones face removal costs ($1,500-$5,000 per dead tree) + replanting + HOA aesthetic concerns. Check your state's department of agriculture quarantine map.

Vapor intrusion (VI)

Migration of volatile organic compounds (VOCs) from contaminated groundwater or soil into the indoor air of an overlying building — a recognized exposure pathway at Superfund + brownfield sites.

EPA's 2015 Vapor Intrusion Technical Guide formalized the pathway. Common contaminants: TCE (former dry cleaners), PCE (industrial degreasing), benzene (gas station spills). Mitigation: sub-slab depressurization ($3,000-$10,000) + indoor air monitoring.

Why it matters: parcels within 100ft of certain Superfund/brownfield sites need a Phase 2 ESA with soil-gas sampling specifically for VI risk. Cross-reference EPA's vapor-intrusion-affected sites list before buying near industrial-zoned land.

AMI (Area Median Income)

HUD's per-metro median household income figure, recalculated annually. Used to determine eligibility for FHA loan-limit overlays, Section 8 vouchers, USDA loans, LIHTC affordable-housing, and many state down-payment-assistance programs.

HUD publishes AMI annually for each MSA + non-metro county area. Programs reference percentages: '80% AMI' = the income-eligibility ceiling for most affordable-housing units. Family-size-adjusted (4-person AMI is the baseline; lower for smaller households).

Why it matters: first-time-homebuyer programs (state HFA loans, down-payment-assistance grants) almost always cap eligibility at 80%-140% AMI. Verify your household's AMI percentage on HUD's calculator before assuming eligibility.

DST (Delaware Statutory Trust) 1031 replacement

Pre-packaged real-estate investment vehicle qualifying as 'like-kind' property under IRS §1031 — lets a property seller defer capital-gains tax by rolling proceeds into a DST instead of buying replacement property directly.

Common exit for landlords selling a single rental who don't want to manage another property but want to defer the $50k-$500k+ capital-gains tax bill. DST sponsors aggregate accredited investors into institutional-grade properties (multifamily, industrial, medical). Typical hold: 5-10 years.

Why it matters: knowing DSTs exist changes the math on selling a rental near retirement age. Always consult a CPA + 1031 qualified intermediary before relying on this — the 45/180-day deadlines and accredited-investor requirements are strict.