Irving, TX Environmental Rules: Stormwater Management (2026)

Chapter 51 of Irving's Code of Civil and Criminal Ordinances, adopted by Ordinance 2025-11145 on August 28, 2025, sets citywide standards for managing post-development stormwater runoff. Section 51-3 makes the property owner responsible for installing all stormwater management improvements, and any system dedicated to the city must follow plans and specifications approved by the City Engineer; once accepted for dedication, no additional fill or structural alteration is allowed over it. Where drainage originates upstream and passes through a lot, or originates on the lot itself, the owner bears responsibility for improvements needed to handle it.

Section 51-4 sets the design storm frequency by drainage area size in Table 51-A: a 25-year storm event for drainage areas under 100 acres, a 50-year event for 100 to 640 acres, and a 100-year event for anything larger. Computations for whether a subdivision will flood, and the sizing of drainage facilities, must follow the North Central Texas Council of Governments' Integrated Stormwater Management (NCTCOG-iSWM) design criteria. Drainage channels must use natural banks and slopes where possible, with concrete lining allowed only when the City Engineer or City Council finds it necessary for an infill site under the Comprehensive Plan or where a grass-lined channel cannot handle offsite runoff velocities.

Owners must demonstrate that the fully-developed 100-year storm stays within the right-of-way, drainage easements, and road low points. Section 51-19 requires an operations and maintenance plan with every development submittal, naming who is responsible for inspecting and maintaining permanent stormwater controls for the life of the structures, the funding source for long-term maintenance, and copies of any maintenance agreements.