What is inclusionary zoning in AP Human Geography?

For AP Human Geography, inclusionary zoning is defined as a housing policy that requires developers to include affordable units in new residential developments, used as a tool to reduce economic segregation and increase mixed-income housing in growing urban areas. A classic example of inclusionary zoning is Montgomery County, Maryland's MPDU program, which requires 12.5 to 15 percent of units in new subdivisions to be moderately priced.

What is an example of inclusionary zoning?

Washington DC's IZ program is a standard example: most new residential buildings with 10 or more units must set aside 8 to 10 percent of floor area at below-market rents in exchange for a 20 percent density bonus, with units allocated by lottery.

How do inclusionary zoning apartments work for renters?

IZ apartments are regular units in market-rate buildings offered at reduced rents to income-qualified households, usually via lottery. Tenants pay their own rent (there is no ongoing subsidy payment), but the rent is capped based on the unit's AMI tier.

Is inclusionary zoning the same as affordable housing?

No. Affordable housing is the umbrella category. Inclusionary zoning is one mechanism for producing it, specifically by embedding affordable units in private market-rate development rather than through public construction or vouchers.

Is inclusionary zoning mandatory?

Depends on the jurisdiction. DC, NYC (in rezoned areas), and Montgomery County run mandatory programs. Many other cities run voluntary, incentive-based programs. Some states, like Texas, prohibit mandatory IZ entirely.

Does inclusionary zoning lower property values?

Research generally finds little to no effect on surrounding property values. The sharper economic debate is about supply: whether IZ requirements slow overall housing production in markets where the math is already thin.

How is inclusionary zoning different from rezoning or a variance?

Rezoning changes what a parcel's zoning allows, and a zoning variance excuses one property from one requirement. Inclusionary zoning is a policy layer that attaches affordability conditions to development that zoning already permits (or to density granted through rezoning).

Who qualifies for inclusionary zoning units?

Households within the program's income band, typically 50 to 80 percent of AMI for rentals, adjusted for household size. Each program publishes its own limits and certification requirements.

Shovels | What Is Inclusionary Zoning? How It Works and Where It Applies

Inclusionary zoning is a local policy that requires or incentivizes developers to include below-market-rate units in new residential projects. Instead of funding affordable housing directly, the city ties affordability to private development. In other words, to build in designated areas, a share of the units must be affordable. It is one of the most widely adopted and most debated housing tools in the country.

Key Takeaways

Inclusionary zoning (IZ) is a policy requiring or encouraging developers to set aside a percentage of new units at below-market rents or prices.

Mandatory vs. voluntary: mandatory programs require set-asides while voluntary programs trade affordability for density bonuses or other incentives.

Typical set-aside: 10 to 25 percent of units, affordable to households earning 50 to 80 percent of area median income (AMI).

Where it lives: more than 1,000 jurisdictions run IZ programs, with Washington DC, NYC, California, and Maryland among the most established.

Tracking programs: Shovels Decisions captures inclusionary zoning ordinances, amendments, and project approvals from local government meetings nationwide.

What is inclusionary zoning?

Here’s the inclusionary zoning definition in short. It’s a land use policy that links approval of new residential development to the inclusion of affordable units. If a developer builds a covered project, a set percentage of units (the set-aside) must be rented or sold below market rate to income-qualified households for a defined affordability period, often 30 years to permanent.

To define inclusionary zoning precisely, it helps to name what it is not. It is not public housing (the units sit inside private, market-rate buildings), not a housing voucher (the subsidy is built into the unit, not paid to the tenant), and not a change to the zoning map. IZ is an overlay on existing zoning rules, usually triggered by project size: a common threshold is 10 or more units.

Jurisdictions adopted IZ because it produces mixed-income buildings in high-opportunity neighborhoods without direct public spending. The cost is borne by the project, which is also the core criticism. More than 1,000 cities and counties now operate some form of IZ program, concentrated in coastal, high-cost markets.

How inclusionary zoning works

Inclusionary zoning laws vary widely, but every program answers the same five design questions:

Is it mandatory or voluntary? Mandatory programs require set-asides in all covered projects. Voluntary programs offer incentives (extra density, height, reduced parking) in exchange for affordable units. Mandatory programs produce more units while voluntary programs only work where the incentive outweighs the cost.
What is the set-aside? Most programs require 10 to 25 percent of units to be affordable.
Affordable to whom? Programs target households by AMI percentage, commonly 50 to 80 percent for rentals and up to 120 percent for ownership units.
What does the developer get? Density bonuses letting the project build more total units than base zoning allows are the standard offset. Fee waivers and expedited permitting are common perks for developers.
Is there an escape hatch? Many programs allow in-lieu fees (paying into a housing fund instead of building units) or off-site construction. Generous in-lieu options tend to shrink on-site production.

For renters and buyers, inclusionary zoning apartments are typically allocated by lottery through the local housing agency, with income certification required at lease-up or sale.

Inclusionary zoning programs by city and state

Washington DC

DC runs one of the strongest mandatory programs in the country. The DC inclusionary zoning program requires 8 to 10 percent of residential floor area in most new projects of 10 or more units to be set aside for households earning 50, 60, or 80 percent of median family income (MFI) in exchange for a 20 percent density bonus.

Units are distributed through DHCD's IZ lottery. Applicants must complete an IZ orientation class first, and the affordability restriction is permanent. Expanded IZ Plus requirements apply in certain upzoned areas.

New York City

NYC's Mandatory Inclusionary Housing (MIH) program, enacted in 2016, applies when land is rezoned to allow more residential density and covers new buildings above 10 units or 12,500 square feet.

Approval options require 20 to 30 percent of residential floor area to be permanently affordable at average AMIs from 40 to 115 percent. Because MIH triggers on rezoning rather than on all development, its footprint grows neighborhood by neighborhood.

California

California authorizes IZ statewide and pairs it with a mandatory density bonus law (Gov. Code section 65915). The law states that projects that include affordable units are entitled to density increases, concessions, and reduced parking. Hundreds of California cities layer local IZ ordinances on top, making it the state with the most programs.

Florida

Florida historically left IZ to local option, and programs exist in cities and counties across the state. The Live Local Act (2023) reshaped the landscape by preempting some local requirements while granting density and height bonuses to qualifying affordable projects. Interested developers should check both the local ordinance and state preemption rules.

Maryland

Montgomery County's Moderately Priced Dwelling Unit (MPDU) program, in effect since 1974, is one of the first inclusionary zoning programs in the country. It’s also the model that many other counties copied.

It requires 12.5 to 15 percent MPDUs in developments of 20 or more units in exchange for a density bonus of up to 22 percent. Roughly 4,000 units remain under price controls today, and the county produced an average of more than 300 new MPDUs a year over the past decade.

Shovels Decisions extracts these zoning actions from meeting records nationwide, so you can track where inclusionary requirements are tightening, where density bonuses are expanding, and which projects are moving through approval.

Does inclusionary zoning work?

The honest answer: it depends on design and market strength.

The case for IZ is that it produces affordable units in high-opportunity neighborhoods where subsidized construction rarely happens, creates mixed-income communities, and costs the public little directly. Programs in strong markets with density bonuses, like Montgomery County's, have produced thousands of units over decades.

The case against comes from economists who note that IZ acts as a tax on new construction. If requirements are set too high without offsetting incentives, developers build less, build elsewhere, or pass costs to market-rate buyers and renters, which can worsen overall affordability. Research findings are mixed overall: studies of well-designed programs show modest or no effect on supply, while studies of aggressive mandates in weak markets show measurable slowdowns.

The design consensus: IZ works best as one tool among several, with meaningful density bonuses, realistic set-asides, and requirements calibrated to what local land economics can absorb.

How to find and qualify for inclusionary zoning housing

For households looking for an IZ unit, the process is similar in most cities:

Find the program. Search your city or county housing department for "inclusionary zoning" or "affordable dwelling unit" programs.
Check income limits. Programs publish AMI-based limits by household size. You typically need to fall within a band (for example, 50 to 80 percent of AMI), not just below a ceiling.
Complete any required orientation. DC, for example, requires an IZ orientation class before entering the lottery.
Enter the lottery and register for buildings. Most cities run centralized portals where you register once and apply to specific buildings as units open.
Certify income at selection. Expect to document income, assets, and household composition before signing a lease or purchase contract.

Tracking inclusionary zoning ordinances, rezonings, and housing decisions across markets? Shovels Decisions turns local government meeting records into structured data. Contact us to learn more.

Frequently Asked Questions

What is inclusionary zoning in AP Human Geography?: For AP Human Geography, inclusionary zoning is defined as a housing policy that requires developers to include affordable units in new residential developments, used as a tool to reduce economic segregation and increase mixed-income housing in growing urban areas. A classic example of inclusionary zoning is Montgomery County, Maryland's MPDU program, which requires 12.5 to 15 percent of units in new subdivisions to be moderately priced.
What is an example of inclusionary zoning?: Washington DC's IZ program is a standard example: most new residential buildings with 10 or more units must set aside 8 to 10 percent of floor area at below-market rents in exchange for a 20 percent density bonus, with units allocated by lottery.
How do inclusionary zoning apartments work for renters?: IZ apartments are regular units in market-rate buildings offered at reduced rents to income-qualified households, usually via lottery. Tenants pay their own rent (there is no ongoing subsidy payment), but the rent is capped based on the unit's AMI tier.
Is inclusionary zoning the same as affordable housing?: No. Affordable housing is the umbrella category. Inclusionary zoning is one mechanism for producing it, specifically by embedding affordable units in private market-rate development rather than through public construction or vouchers.
Is inclusionary zoning mandatory?: Depends on the jurisdiction. DC, NYC (in rezoned areas), and Montgomery County run mandatory programs. Many other cities run voluntary, incentive-based programs. Some states, like Texas, prohibit mandatory IZ entirely.
Does inclusionary zoning lower property values?: Research generally finds little to no effect on surrounding property values. The sharper economic debate is about supply: whether IZ requirements slow overall housing production in markets where the math is already thin.
How is inclusionary zoning different from rezoning or a variance?: Rezoning changes what a parcel's zoning allows, and a zoning variance excuses one property from one requirement. Inclusionary zoning is a policy layer that attaches affordability conditions to development that zoning already permits (or to density granted through rezoning).
Who qualifies for inclusionary zoning units?: Households within the program's income band, typically 50 to 80 percent of AMI for rentals, adjusted for household size. Each program publishes its own limits and certification requirements.