Zoning classifications by city

R1 zoning (single-family residential)

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

ADU (Accessory Dwelling Unit)

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

As-of-right (zoning)

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

Variance (zoning)

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

Setback

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

ADA compliance (Americans with Disabilities Act)

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

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.

Property tax millage — what 'mill' means and how your bill is computed

Plain-English guide to property tax millage rates, assessment ratios, and homestead exemptions. How county assessors compute your annual property tax bill.

Deed records — what they show and what they don't

Plain-English guide to county deed records: what gets filed, how to look up a property's history, and why zipradar aggregates only counts (never owner names).

Zoning codes — what R-1, C-2, M-1, MU mean and why your house is one

Plain-English guide to common US zoning codes: R-1 / R-2 / C-1 / C-2 / M-1 / MU. Why zoning matters for your home, your neighbors, and what you can build.

Homestead exemption — state-by-state property tax savings

Every US state offers a homestead exemption that reduces property tax for owner-occupied homes. State-by-state amounts and how to file.

NCES Common Core of Data — what district boundaries actually mean for buyers

How NCES district boundaries, school ratings, and student-teacher ratios feed real-estate decisions — and what the data does NOT tell you.

County assessor data — how millage rates and assessments actually combine

Property tax = assessment × millage rate, but the math has caveats. Here's how zipradar pulls + normalizes county assessor data across the top 50 metros.

Zoning overlays — historic, flood, environmental layers that change what you can build

Base zoning codes (R-1, C-2, M-1) are only half the story. Special overlays — historic districts, floodplain, conservation, scenic — add a second rule layer. Here's what each one does.

EPA Superfund + Brownfields — what 'contaminated site nearby' actually means

EPA's National Priorities List (Superfund) flags the most contaminated sites in the US. Brownfields tracks lower-tier abandoned-industrial sites. Here's how to read both.

HOA + deed restrictions vs. zoning — three regimes that govern what you can do

Zoning, HOA covenants (CC&Rs), and deed restrictions are three separate regimes. Each one can override the others on different things. Here's how to read all three.

Permit history + unpermitted work — what to verify before close

How to pull permit history from city building departments, why unpermitted additions hurt resale + insurance, and the gotchas before closing on a renovated property.

Phase 1 Environmental Site Assessment — when you need one, what it costs, what it finds

A Phase 1 ESA is the standard environmental due-diligence for commercial real estate + some residential. Plain-English guide to when one is required, what it covers, and the $1,500-5,000 cost.

Easements + rights of way — how the legal markings on your survey actually affect what you can build

Utility easements, drainage easements, ingress/egress, and conservation easements each restrict different building rights on your parcel. Plain-English buyer guide with survey-reading tips.