Zero Lot Line: What It Means and Rules in 5 Codes

A zero lot line is a property line with no setback: the house is built right up to it, so one side yard is zero feet wide. A zero lot line home usually sits on one side line and keeps one wider yard on the other. Most codes we read put a maintenance easement on the neighboring lot.

This guide is written by Pillar, which makes land research software. We checked the source text used here on November 15, 2026. Every Miami-Dade and Austin rule below comes from the eLaws copies of those codes. We could not open the official publisher, Municode, to confirm them. Codes change and carry conditions we don't repeat. This is general information, not legal advice, so confirm the rules for your lot with the local planning and building departments and a licensed professional in your state.

What is a zero lot line?

Sacramento County's zoning code defines zero lot line as "A design which allows a residential structure to be constructed up to one of the interior side property lines of a parcel."

A setback is the open yard zoning requires between a building and a lot line. A zero lot line layout removes one. Hopkinsville, Kentucky, states the reason in its zero lot line section: "By placing the dwelling against one of the property lines, permitting the outdoor space to be grouped and utilized to its maximum benefit."

The term covers three building forms in the codes we read:

• A detached house on one side line. It touches no other building and has one usable side yard.
• Attached pairs. Two homes share a wall on the lot line. Sacramento County calls this a halfplex: a two-unit building "where each dwelling unit is located on a lot that may be separately owned or conveyed."
• Attached homes with a zero setback on both sides. Hopkinsville's attached-dwelling provision allows a zero setback on both interior side lines. The same section separately requires at least 10 feet between dwellings on adjacent lots, so ask the city how it applies the two to an attached proposal.

The term describes where a building sits, not who owns the land. Miami-Dade County and Hopkinsville both require each dwelling to be on its own individually platted lot.

How do zero lot line rules work? Five codes side by side

These five codes come from five states. Each entry gives where the layout is allowed, the yard on the other side, the spacing between buildings, the easement on the neighbor's lot and the limits on openings in the wall.

• Miami-Dade County, Florida. In the eLaws copy of the county code, Section 33-284.42 says a zero lot line development of up to six units per net acre, for one-family dwellings only, may be permitted in the RU-1Z, RU-2, RU-TH, RU-3, RU-3M, RU-4, RU-4A, RU-4L and RU-4M districts without a public hearing once the Department approves the site plan and the article's other conditions are met. Section 33-284.43 puts the dwelling, or part of it, on one interior side line with a zero setback and requires at least 10 feet on the other side. A unit at the end of a row need not sit on the zero line where it could not be placed on a separate zero lot line without attaching it to an adjacent unit. It must then be at least 10 feet from the residence on the adjacent zero lot line lot. The adjacent lot carries a "perpetual four-foot wall-maintenance easement," kept clear of structures other than walls and fences. The wall on the line "shall have no windows, doors, air-conditioning units, or any other type of openings," with three listed exceptions: atriums or courts enclosed by three walls of the dwelling, with a solid wall at least 8 feet high on the zero lot line built of the same material as the unit's exterior walls; windows at least 6 feet above "the finished floor level of any floor adjacent to the wall below the window"; and windows on a building wall perpendicular to the zero lot line, or windows at least 10 feet from the property line. Confirm the current text in the official code on Municode.
• Norfolk, Nebraska. City Code Sec. 27-104 allows zero lot lines for single-family detached houses in District R-2 (text last amended by a November 20, 2023 ordinance). The opposite side yard is 14 feet, "In no case shall there be less than fourteen (14) feet between buildings," and the adjoining lot provides a 5-foot easement "for maintenance, repair, and roof drainage." On openings: "There shall be no openings in a wall on a zero lot line."
• Hopkinsville, Kentucky. Section 158.061 permits zero lot line developments by right in the R-3, R-4 and R-5 districts and by conditional use permit in the EST-1, R-1 and R-2 zones. A detached house goes on one interior side line and keeps at least 10 feet on the other. Dwellings on adjacent lots must be at least 10 feet apart. Detached dwellings get a perpetual 4-foot wall-maintenance easement on the adjacent lot. The wall on the line has no windows, doors, air conditioning units or other openings, except an atrium or court enclosed by three walls of the dwelling, with a solid wall at least 8 feet high on the zero lot line built of the same material as the unit's exterior walls.
• Inglewood, California. In the R-1Z One-Family/Zero-Lot-Line zone, a house may sit on one side lot line, or within 5 feet of it, if the zero side abuts the open side yard or rear yard of another R-1Z lot. The opposite, open side yard must be at least 10 feet wide, with no accessory structure in it. An easement on the abutting lot must give the owner access "to maintain, repair or improve the exterior portion of the structure located upon the zero side yard." The article states no width. No openings are allowed in an exterior wall "located upon or oriented towards the zero side yard," except an alcove or atrium recessed behind a solid wall at least 8 feet high.
• Austin, Texas. The eLaws copy of Land Development Code § 25-4-232, on small lot subdivisions, says "A lot may have one zero lot line." Combined side yard setbacks may not be less than 7 feet, and structures on adjoining lots must be at least 7 feet apart, except for a patio or patio cover. A wall "built adjacent to a zero lot line or within three feet of a common side lot line must be solid and opaque and may not contain an opening." The section requires a maintenance easement in the dominant side yard and a use easement in the subordinate side yard, and states no width for either. Confirm the current text on Municode.

Where these codes state a figure, the open side runs from a combined 7 feet (Austin) to 14 feet (Norfolk). The easement is 4 feet in Miami-Dade and Hopkinsville and 5 feet in Norfolk. Inglewood and Austin state no width. None of these figures is a national standard.

What is a zero lot line maintenance easement?

A wall on the line can only be reached from the neighbor's land. The maintenance easement is the recorded right to go there to maintain it. Like any easement, it is a right to use someone else's land for a stated purpose.

The codes above say where the easement must be written down:

• On the plat. Miami-Dade requires that the plat "indicate the zero lot lines and easements appurtenant thereto." Norfolk says "The zero lot line and easements shall be established on the subdivision plat." See how to read a plat map.
• In the deeds. Miami-Dade's easement "shall be shown on the plat and incorporated into each deed transferring title to the property."
• In recorded restrictions. Austin will not record a small lot subdivision plat unless a Declaration of Covenants, Easements, and Restrictions or similar document has been approved by the city attorney, recorded and referenced on the plat. It must provide for the maintenance and use easements. Read it like any deed restriction.
• In a separate recorded agreement. West Sacramento, California lets interior setbacks along lines adjoining other private lots be waived by a zero lot line agreement approved in writing by the City and the adjoining owner and recorded on the chain of title of both properties. Among its conditions, "Where the setback is reduced to less than three feet, a maintenance access easement of five feet in width shall be provided on the adjoining property." Norfolk also requires a recorded party wall agreement before a certificate of occupancy when a zero lot line is used for a detached house. It must "set terms for maintenance and upkeep of the entire structure and individual units including color, materials and access for maintenance and repairs."

A code requirement does not prove an easement was recorded for a given lot. The recorded documents set what the neighbor may do.

Can a zero lot line house have windows on the lot line wall?

Usually not. Zoning is the first reason. All five codes above ban or tightly limit openings in the wall on the line.

The building code is the second. Residential codes regulate exterior walls by fire separation distance. The 2021 International Residential Code, a model code, defines it as the distance from the building face to the closest interior lot line, to the centerline of a street, alley or public way, or to an imaginary line between two buildings on the lot. A wall on a side lot line has a distance of zero.

A model code is law only where a state or city adopts it, often with changes. Take Minnesota. Its residential code incorporates the 2018 edition with state amendments, including replacement tables for section R302.1. In Table R302.1(1) of Minnesota Rules, part 1309.0302, a wall that is not fire-resistance rated needs at least 5 feet of fire separation distance. The rated-wall row, which starts at 0 feet, calls for "1 hour," tested "with exposure from both sides." Openings in walls are "Not allowed" at less than 3 feet, limited to 25 percent of wall area at 3 feet and unlimited at 5 feet. Section R302.1 of the 2018 code applies Table R302.1(2) instead to dwellings "equipped throughout with an automatic sprinkler system installed in accordance with Section P2904." A footnote to Minnesota's version of that table allows further reductions in subdivisions where all dwellings have that system and "the adjoining lot provides an open setback yard that is 6 feet or more in width on the opposite side of the property line." Section R302.1 also lists exceptions, including walls "perpendicular to the line used to determine the fire separation distance" and "Walls of individual dwelling units and their accessory structures located on the same lot."

Ask the local building department which edition, amendments and exceptions apply to a wall, eave or vent on the line.

Zero lot line vs townhouse, duplex and condo

Zero lot line is about where the wall sits. The other terms describe the building or the ownership.

• Townhouse. The 2021 International Residential Code defines a townhouse unit as "A single-family dwelling unit in a townhouse that extends from foundation to roof and that has a yard or public way on not less than two sides." Sacramento County's term is single-family attached: "An attached dwelling unit entirely within a separate, privately owned lot," where the property line "must follow the common wall of adjoining units." As we read it, a townhouse on its own lot is zero lot line on each shared wall, while a detached zero lot line house shares no wall.
• Duplex. Sacramento County defines a duplex as a building for two households, each in a separate dwelling unit, "on one lot." Where each unit is on its own lot, the county's term is halfplex.
• Condominium. A condominium is a form of ownership, not a building shape. Florida Statutes § 718.103 defines it as ownership "comprised entirely of units that may be owned by one or more persons," with "an undivided share in common elements" attached to each unit. What a unit includes is "specified in the declaration."
• Patio home. The codes we read do not define it. Check the plat to see where the lot lines fall.

Zero lot line pros and cons

Pros

• One usable yard instead of two strips. In Norfolk, a standard detached house on an interior R-2 lot has 7-foot side yards, and the zero lot line version has 14 feet on one side.
• Less land per house. Hopkinsville's first stated purpose is "The more efficient use of land, as compared with the typical single-family development, making available needed housing at a more affordable cost."

Cons

• Privacy and light. The openings rules leave the wall on the line mostly blank, and the open yard faces the neighbor's blank wall.
• Drainage. Miami-Dade allows roof overhangs to extend up to 24 inches into the easement, but the roof must be designed so runoff "is limited to the easement area." Norfolk's easement covers roof drainage by name.
• Fences. Miami-Dade and Hopkinsville keep the easement clear of structures but except walls and fences, so those sections do not ban a fence there. The neighbor's access right remains, so read the recorded easement and restrictions before building one.
• Additions. Inglewood caps lot coverage at 50 percent and bars accessory structures in the open side yard. Anything built in the easement strip can become an encroachment.
• A neighbor's say over your wall. In Miami-Dade the wall must be "maintained in its original color and treatment unless otherwise agreed to in writing by the two (2) affected lot owners."

Buying or developing zero lot line land

Lot yield. Removing one setback does not by itself add lots. In Norfolk's R-2 district the minimum lot is 40 feet wide and 4,000 square feet for both a standard detached house and a zero lot line house. On an interior lot with 7-foot side yards the house can be 26 feet wide (40 − 7 − 7). With a zero lot line it can be 26 feet wide (40 − 14 − 0). The lot count is the same. Only the yard changes.

Yield rises when the code pairs the layout with smaller lots. Miami-Dade sets a 4,500-square-foot, 45-foot-wide minimum for zero lot line lots on sites zoned RU-1Z, and requires two lots of at least 5,000 square feet for each lot under 5,000. For example, lots of 4,500, 5,000 and 5,000 square feet average 4,833 square feet by our arithmetic, about nine lots per acre of lot area. But Section 33-284.42 allows only six units per net acre without a public hearing. Test lot size, lot width and the density cap. Where the base district has no such option, ask the planning department whether a planned unit development can vary the side setback. Our R1 zoning guide compares standard single-family setbacks in ten codes.

What to read before an offer

1. The recorded plat. Find which side of each lot is the zero line and where the easement falls.
2. The easement terms. Width and purpose: maintenance, drainage, roof overhang, footings.
3. The restrictions. Declarations and party wall agreements can set wall color and maintenance terms. Inglewood's R-1Z article says nothing in the chapter precludes additional limits imposed by a homeowners association.
4. A survey. Ask a licensed surveyor to locate the wall, roof overhangs and fences relative to the line and the recorded easement, and give them the plat, easement documents and title commitment. What a boundary survey must show varies by state, so confirm the scope covers those features.
5. The title commitment. Compare its listed easements and exceptions with the plat.

Building or adding on the line. Confirm the zoning district allows a zero setback on that side. Without that, a wall on the line needs relief such as a variance. Then confirm the wall rating and opening limits with the building department, have a surveyor stake the line, and confirm the neighbor-side easement is recorded.

Pillar's property search shows parcel boundaries with acreage, zoning and land use on the parcel record. It does not show recorded easements or wall locations. Those come from the plat and a survey.

Quick answers

Is a zero lot line home the same as a townhouse? No. A townhouse is attached to its neighbors. A zero lot line home can be detached, with one wall on the line and an open yard on the other side.

Can my neighbor come into my yard to fix their wall? If a maintenance easement is recorded on your lot, yes, for the purposes it states. The five codes above require 4 or 5 feet where they state a width.

Can I build a fence on a zero lot line? It depends on the recorded easement and local code. Miami-Dade and Hopkinsville allow walls and fences in the easement strip.

Can I put a window in the wall on the lot line? Usually not. The five zoning codes above ban or limit openings there, and Minnesota's Table R302.1(1) does not allow openings at less than 3 feet of fire separation distance.

How do I know if a lot is zero lot line? Read the recorded plat and the zoning district's rules, then compare with a survey. See how to find property lines.