Chester County Courthouse

Why do inspectors reference the Authority Having Jurisdiction? Why don’t we just say something “is not to code” when we observe something that is, well, not to some code? Here’s why, with the necessary background.

Code models

The International Building Code (IBC) is the core model that defines the base regulations and minimum standards for residential and commercial buildings. All States follow the IBC. If that was all there was to it, all buildings would be good, and life for a home inspector or commercial inspector would be simple. However, the IBC is intended to be adopted to accommodate laws and practices for any region. For example, a Florida beach home has to withstand storm surges whereas a California home has to withstand seismic activity. Both have the IBC at the core, specialized to accommodate regional needs.

There are also code models for other aspects. The National Electric Code (NEC) is a set of standards for electrical systems. Similarly for the International Plumbing Codes (IPC), the National Fire Protection Association (NFPA) and so on. Even Health Departments and Fire Chiefs have a say. Each of these code sets can be amended, and sometimes those amendments contradict each other. Many codes are so elemental that they don’t need to amended.


Think of the jurisdiction as an area, like a State, which has jurisdictions inside it, like Counties, which in turn again have jurisdictions within it like Municipalities or Boroughs or Townships. For example, every Pennsylvania County has a set of codes that extends the State baseline. Within the County, the Township jurisdictions have their set of altered codes. There often are multiple variants for the same code. The jurisdictions are layered like an onion with the IBC at the core.

Authority Having Jurisdiction (AHJ)

The last level of jurisdiction that amended some codes has the authority when it comes to specifics or conflicts of that code. That authority could be a team of people in a large city or a single person in a small town. If a jurisdiction did not amend a specific code, then the previous layer applies and so on. The AHJ has the last word, and that is good.

A judicious home inspector will not use a four-letter word like code because we cannot possibly know how the code varies through the layers of jurisdictions. Hence, we reference the AHJ for implementation specifics.


Chester County Home Inspections operate in multiple jurisdictions without knowing where the lines are drawn. What applies in West Chester does not necessarily apply in Exton or Downingtown. We are based in West Pikeland Township but we cover Bucks, Berks, Delaware and other counties, each with their townships or boroughs and layers of jurisdictions. It is an onion farm, really.

We are knowledgeable in all aspects of the IBC, NEC and IPC in principle, then we apply common sense when something is not within best practices as we encounter them from community to community. Schedule online now, or inquire online, or call or text (484) 212-1600.