County Laws & Code

Complete County Code
The complete county code is maintained by Municipal Code Corporation, the nation's leading codifier.

This online document is updated bimonthly. In order to keep pace with changes to Chapter 40 of the county Code, an up to date copy of this chapter is made available below. Also, selected chapters are available below in PDF format.

Unified Development Code
Chapter 40 of the county Code is the primary guide to development within New Castle County. The Unified Development Code (UDC) establishes standards, procedures, and minimum requirements, consistent with the Comprehensive Development Plan.

The code regulates and controls the following:
  • Creation and administration of zoning districts
  • General development of real estate in the unincorporated areas of New Castle County
  • Planning and subdivision of lands
  • Use, bulk, design and location of land and buildings
Building Code
New Castle County has adopted, with amendments, the following codes:
  • International Building Code, 2015 edition
  • International Residential Code, 2015 edition
  • International Existing Building Code, 2015 edition
  • International Swimming Pool and Spa Code, 2015 edition

Additionally, the Department will enforce of the following codes on their respective effective date listed.

        International Energy Conservation Code 2012 – now being enforced

        International Mechanical Code, 2015 edition – August 1, 2015

        International Fuel Gas Code, 2015 edition – August 1, 2015

        International Plumbing Code, 2015 edition – August 1, 2015

All projects submitted on or after June 1, 2015 will be reviewed using the new regulations.  To receive additional extension between June 1, 2015 and August 31, 2015, the contractor or design professional must request the extension in writing and demonstrate the hardship for transitioning to the 2015 codes.

 The NCC amendments for the building code are available for download on the County’s website.  See for the administrative and adopted code amendment sections.  Code books are available for purchase through various vendors, including the International Code Council’s website at  New Castle County also has code books available for purchase.

Property Maintenance Code
Chapter 7 of the New Castle County code deals with property maintenance and enforcement.