Can I build here? Check any lot in seconds

Type the address of a lot or a house you might tear down. We check official public data live and tell you who issues the permits, whether it sits in a FEMA flood zone, whether it can use public sewer, and which builders work there.

Why the mailing address misleads

Much of Northern Virginia uses postal town names that aren’t governments. A house with a McLean, Great Falls, Annandale or Oakton address is in unincorporated Fairfax County, and many homes with a Falls Church or Alexandria mailing address are in Fairfax County too, not the independent cities. The permit office, zoning rules and fees follow the jurisdiction, not the post office. The checker uses the U.S. Census Bureau’s address file to find the county and any incorporated town or city the lot is actually in.

Some lots answer to two governments. The Town of Vienna, the Town of Clifton, the Town of Leesburg and the Chevy Chase municipalities in Maryland each have their own approvals on top of the county’s building permit. The result tells you when that applies and links to the official page.

Flood zones

The checker asks FEMA’s National Flood Hazard Layer about the exact point. Zones starting with A (such as AE) are the Special Flood Hazard Area, where flooding has a 1% chance in any year. Building there brings extra rules, and lenders usually require flood insurance. Shaded Zone X is the 0.2% annual chance area; unshaded Zone X is minimal risk. A large lot can cross zone lines, so open the FEMA map for the whole parcel before you buy.

Public sewer or septic

• Fairfax County: we check the county’s Approved Sewer Service Area map. Inside it, a home must connect where a sewer main is within 300 feet. Outside it, public sewer generally isn’t available and you should plan on septic, which needs suitable soil and space.
• Montgomery County, Maryland: we read the water and sewer category the county assigns to every property. Category 1 is existing community service; categories 4 and 5 are planned for the future; category 6 generally means a well and septic.
• Elsewhere: we point you to the right utility or permit office to ask.

What it doesn’t check

Zoning district and setbacks, Resource Protection Areas, easements, covenants, tree rules, slopes and soils all shape what you can build. Use our lot checklist for those, and ask a builder for a feasibility review before you buy. Several builders we list offer one.

Sources

• U.S. Census Bureau Geocoder: https://geocoding.geo.census.gov/geocoder/
• FEMA National Flood Hazard Layer and Flood Map Service Center: https://msc.fema.gov/portal/search
• Fairfax County, connecting to the public sewer system: https://www.fairfaxcounty.gov/publicworks/wastewater/connecting-public-system
• Montgomery County DEP, water and sewer service area categories: https://montgomerycountymd.gov/DEP/water/water-supply-wastewater/service-area-categories.html

Data checked live each time you search. We don’t save the address you type.