New Inclusionary Zoning Tool Available for NAHB Members

Economics
Published

Combating the housing affordability crisis requires comprehensive strategies at the federal, state and local levels to reduce building costs, boost supply and empower home buyers with a mix of housing choices. One strategy that many communities have adopted is inclusionary zoning (IZ) — local government ordinances that require a certain percentage of new residential construction to be sold or rented at below-market rates.

IZ is often adopted under the assumption that it is a simple, expedient method to address affordable housing. However, IZ is far more complicated, and there is conflicting evidence on the extent to which IZ discourages development, raises the price of market-rate homes, creates adequate affordable housing supply, or encourages economic opportunity.

Some evidence over the past decade has shown IZ to be an ineffective tool at promoting affordable housing as it acts as a tax on housing and shifts costs either to market-rate renters and home buyers, or causes developers to build elsewhere.

NAHB has created an empirical tool, the Inclusionary Zoning Calculator Tool, which aims to supplement these conflicting policy studies with concrete data of how IZ requirements impact development choices, including whether or not a developer proceeds on a project. The IZ Calculator Tool uses a sample developer's pro forma as the template, and allows the end user to input and manipulate certain variables to show how different incentives and cost inputs may be used to create an economically feasible development.

NAHB's IZ Calculator Tool comprises two Excel spreadsheets designed to show the effects of IZ on the pro forma for a development consisting of homes built for sale:

  • Acquisitions, Development and Construction (AD&C) Calculator Tool: AD&C has inputs and requires cost data for development of lots and construction of housing units.
  • Acquisition and Development (AD) Calculator Tool: AD has inputs and requires data for the development of lots only.

Both spreadsheets allow the user to input acquisition and development costs (A&D version), and one of the tools give you the added control of inputting housing unit construction costs (AD&C version). Both versions start with a sheet of general instructions containing links to each page that requires inputs from the user.

The tool can be used by developers, local governments and other stakeholders with an interest in increasing the supply of affordable housing.

To access the tool, and other resources, visit nahb.org.

Subscribe to NAHBNow

Log in or create account to subscribe to notifications of new posts.

Log in to subscribe

Latest from NAHBNow

Environmental Issues

May 30, 2025

NAHB Members Provide Final Recommendations for New WOTUS Rule

NAHB members concluded their participation in multiple “waters of the United States” (WOTUS) listening sessions with strong showings in Washington, D.C., and Salt Lake City. In total, 12 NAHB members and four staff members from NAHB and state home builder associations (HBAs), representing 11 states, provided oral statements at listening sessions.

Workforce Development

May 30, 2025

Statement from NAHB Chairman Buddy Hughes on DOL Decision to Pause Job Corps Center Operations

NAHB Chairman Buddy Hughes issued the following statement after the Department of Labor announced it was pausing Job Corps center operations nationwide.

View all

Latest Economic News

Economics

May 30, 2025

Multifamily Absorption Moves Lower for New Apartments

The percentage of new apartment units that were absorbed within three months after completion continued to trend lower, according to the Census Bureau’s latest release of the Survey of Market Absorption of New Multifamily Units (SOMA).

Economics

May 29, 2025

Treasury Yield Increase Drives Mortgage Rates Higher in May

Mortgage rates continued their upward trend in May due to market volatility triggered by fiscal concerns and weaker U.S. Treasury demand. According to Freddie Mac, the average 30-year fixed-rate mortgage rose to 6.82% — a 9-basis-point (bps) increase from April. The 15-year fixed-rate mortgage increased by 5 bps to 5.95%.

Economics

May 28, 2025

Aging-in-Place Remodeling Work Fell While Familiarity and Receptiveness Remain High

Only 56% of professional remodelers undertake projects designed to allow homeowners to Age-in-Place (AIP), according to results from NAHB’s Q1 2025 Remodeling Market Index (RMI) survey.