Multi-family property, such as an apartment building, usually needs a multi-family residential district like R-3, R-4 or RM, and many cities also allow apartments in mixed-use zones. The district's density limits, not its name, decide how many units a lot can hold.
New to zoning types? Read what residential zoning means and what it allows.
R - Residential
or
MU - Mixed-Use
Is a multi-family property allowed in Columbus?
Open the Columbus zoning map to find a property's zoning district, then check what that district allows.
Check zoning in Columbus, OH →Multi-family zoning is a residential district where buildings with several separate dwelling units are allowed, usually three or more. Codes name these districts in different ways, but most sort them by density.
| Tier | Common names | Typical buildings |
|---|---|---|
| Low-density multi-family | R-3, RM-1, MF-1 | Triplexes, fourplexes, townhouses, small garden apartments |
| Medium-density | R-4, RM-2, MF-2 | Two- to four-story apartment buildings |
| High-density | R-5, RH, MF-3 | Mid-rise and high-rise apartments |
The labels change from city to city, so the district's use table and density rules matter more than the name. Our residential zoning guide explains how these tiers fit with single-family districts.
Multi-family zoning requirements are mostly about how much building the lot can hold. Codes use one or more of these tools:
The tightest rule wins. If a code asks for 1,000 square feet of lot area per unit, for example, a 20,000 square foot lot tops out at 20 units, even if the height limit would fit more. The floor area ratio calculator helps you test a site.
Multi-family housing isn't limited to residential districts. Many cities allow apartments in mixed-use zones, often above ground-floor shops, and some allow them in downtown or general commercial zones. A commercial lot can sometimes be a faster path to apartments than rezoning residential land, but these districts may require ground-floor retail or limit units on the street level.
For zoning, multi-family is a residential use, even when one company owns and rents every unit. For building codes, apartment houses are their own occupancy, Group R-2 under the International Building Code, which covers buildings with more than two dwelling units. That brings stricter fire and exit rules than a house.
The business side is different. Larger apartment buildings are usually bought, financed and appraised as commercial real estate, based on the rent they produce. So a property can be residential on the zoning map and commercial to a lender.
Parking minimums are often set per unit or per bedroom, and on tight sites they can cut the unit count more than density does. Many cities have lowered or dropped parking minimums near transit, so check the current code rather than an old rule of thumb. The parking calculator gives a first estimate.
Some cities have inclusionary zoning, which requires a share of new units to be rented or sold below market, often in exchange for extra density. Projects of any real size also go through site plan review, which can cover traffic, utilities, drainage and building design. Our affordable housing zoning guide covers density bonuses in more detail.
For smaller buildings, compare the rules for a triplex or duplex.
Single-family zoning usually allows one detached home per lot. Multi-family zoning allows buildings with several units, at densities the code sets for each district. Our single-family home zoning guide explains that side.
Usually yes. Higher-density residential zones often allow lower-density housing too, though some codes set a minimum density that a duplex on a large lot might not meet.
Often, yes. Small group homes are commonly allowed in residential zones, and larger ones may need a conditional use permit. Federal fair housing law also limits how cities can restrict homes for people with disabilities.
Look at your city's zoning map for districts labeled RM, MF, R-3 or higher, along with mixed-use districts. A commercial real estate broker or the planning department can also point you to sites that allow apartments.