2025/06/25

The "One House Rule": Understanding Your Township's Zoning and the Principal Structure Concept

 

For many homeowners, the dream of building a guest house, converting a garage into an apartment, or simply adding a small cottage to their property seems like a great way to enhance family space, generate extra income, or accommodate aging parents. However, before you start drawing up blueprints, you need to understand a critical component of your township's zoning ordinance: the "principal structure" rule.

In many residential zones, a key regulation stipulates that only one "principal structure" is permitted per lot. This seemingly simple concept can have significant implications for homeowners and potential builders, impacting everything from accessory dwelling units (ADUs) to subdividing property.

What exactly is a "Principal Structure"?

The definition of "principal structure" is the bedrock of this rule. Typically, a principal structure is the primary building on a lot, often the house where the main residential activity occurs. Think of it as the main dwelling unit that establishes the property's residential character. Zoning ordinances usually outline specific characteristics to help identify a principal structure, such as:

  • Size and Purpose: It's typically the largest building on the lot and used primarily for residential purposes.
  • Essential Infrastructure: It generally contains the core utilities and infrastructure, like plumbing, electrical, and heating systems, serving the primary residential use.
  • Original Intent: Often, it's the structure that was originally intended as the primary dwelling when the lot was created.

Why the "One Principal Structure" Rule?

This zoning regulation exists to:

  • Maintain Residential Character: Limiting principal structures helps preserve the character and density of residential neighborhoods, preventing them from transforming into high-density areas.
  • Control Population Density: By restricting the number of dwelling units, the township can effectively manage population density and the strain on local infrastructure and services.
  • Manage Infrastructure Capacity: The rule helps ensure adequate infrastructure, such as roads, sewer systems, and water supply, can support the residential population within a specific zone.
  • Prevent Overcrowding: It prevents the overcrowding of lots, ensuring sufficient space for residents to live comfortably and maintain a reasonable quality of life.

Implications for Homeowners:

Understanding the "one principal structure" rule is crucial before undertaking any construction project. Here are some key considerations:

  • Accessory Dwelling Units (ADUs): While many townships are embracing ADUs to address housing needs, their regulations must comply with the principal structure rule. This often means ADUs are considered accessory to the main dwelling and are subject to strict regulations regarding size, location, and occupancy.
  • Detached Garages and Sheds: These structures are generally considered accessory buildings and not principal structures, but they still need to comply with zoning requirements regarding setbacks, size, and use.
  • Subdivision: If you're considering subdividing your property, this rule dictates that each newly created lot must be able to accommodate a principal structure that complies with all zoning regulations.
  • Converting Existing Structures: Modifying an existing garage or shed into a separate dwelling unit will likely violate the "one principal structure" rule unless it's specifically permitted as an ADU and meets all related criteria.

Before You Build: Consult Your Township

Zoning ordinances can be complex and vary significantly between townships. Therefore, it's absolutely essential to consult with your local zoning department before starting any construction project. They can provide clarification on the specific definition of "principal structure" in your area, explain the applicable regulations, and guide you through the permitting process.

Ignoring the "one principal structure" rule can lead to costly consequences, including fines, stop-work orders, and even the requirement to remove non-compliant structures. By understanding your township's zoning regulations and engaging with local officials, you can ensure your building project aligns with the rules and achieves your desired outcome without running into legal or financial roadblocks.

In conclusion, the "one principal structure" rule is a vital element of many township zoning ordinances. Understanding its purpose and implications is crucial for homeowners to ensure they are building ethically and within the legal framework of their community. So, before you start building, do your research, ask questions, and consult with your local zoning department. Your peace of mind and the integrity of your property depend on it.