Planning and Development - Division of Planning, Zoning and Land Use

Unified Development Ordinance

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The Unified Development Ordinance (UDO) integrates Zoning, Subdivision, and related development regulations into one consolidated ordinance.

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The Unified Development Ordinance (UDO) regulates land use in unincorporated McHenry County: 


The County Board adopted the UDO in October of 2014. The most recent amendments were adopted March 19, 2018.  

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Unified Development Ordinance Overview 

This UDO is the County's key tool for implementing many of the policies contained in the 2030 Comprehensive Plan and the 2030 and Beyond Comprehensive Plan Update. It regulates the use of land, the siting and sizing of new structures, signs, subdivisions, and other development controls.   

Effective Date

The UDO became effective October 22, 2014 . Text amendments to the UDO were adopted January 19, 2016, March 17, 2016, and March 19, 2018.  

Frequently Asked Questions

What is zoning ?
Zoning regulates how land is used, where a structure may locate on a lot, and how tall and large that structure can be. It also regulates other elements of site development, such as accessory structures, temporary uses, parking, landscaping and signs. Zoning regulations are divided into zoning districts, so that use, bulk, yard and development regulations are tailored to the character of the particular zoning district. 

What is subdivision ?
Subdivision regulations provide the rules for dividing up land into buildable lots as well as the rules for street and access design, proper drainage, required utilities, and well and septic design that serve those lots. In addition, the subdivision regulations also contain the regulations for conservation design, which apply to proposed subdivisions that contain and/or abut sensitive natural resource areas. 

What is a Unified Development Ordinance ?
A Unified Development Ordinance combines zoning and subdivision regulations, as well as other County ordinances, such as the sign regulations, into a single ordinance. The UDO is the "rule book" for land development and building within the County. Currently these "rules" are contained in separate ordinances in the County Code. The purpose of combining these and kindred ordinances is to assure consistency among development requirements, make it easier to develop land within the County, and to make sure that the County's review and approval processes are as complete and efficient as possible. The ordinance will also contain cross-references to other County Codes that are not part of the new UDO, such as the Stormwater Management Ordinance, to ensure that the user is aware of all applicable regulations. 

What is the relationship between the Comprehensive Plan and the UDO ?
The UDO is one of the key tools to implement the McHenry County Comprehensive Plan, which includes the 2030 and Beyond Update. The Comprehensive Plan provides mapped and written policy about how land should be managed and how development upon the land should occur. The UDO takes these policies as its base and provides a set of development requirements, generally organized by zoning district, each containing specific regulations key to those policies. A zoning map identifies the location of these districts, thereby specifying the development requirements affecting each parcel of land within the County. 

Does the UDO regulate land within the corporate limits of municipalities within the County ?
No. The UDO regulates only land that is outside of municipal boundaries, generally referred to as unincorporated McHenry County. Municipalities within McHenry County each have their own zoning ordinance and subdivision regulations. 


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