Elgin, IL Building Safety: Fire Sprinkler Requirements (2026)

04, splits residential fire sprinkler requirements by annexation date. For a one- or two-family dwelling or townhouse on land that was within the City of Elgin as of July 11, 2018, the code requires fire sprinkler protection in the basement area only, and that basement system can tie into the domestic water supply without backflow prevention as long as it is a looped system with no dead-ends longer than 2 feet. Four exceptions can eliminate even that basement sprinkler requirement: wood I-joists or open web trusses protected with 1/2-inch gypsum wallboard or equivalent on the floor's underside; wood floor assemblies using dimensional or structural composite lumber at least 2-by-10 nominal or an equivalent approved assembly; additions or alterations to an existing one- or two-family home that never had a sprinkler system; and wood I-joists protected with a factory-applied 'Flak Jacket' or approved equal, though that coating must be reevaluated by a licensed architect or engineer if it has been exposed to activating heat.

Whenever one of those exceptions applies, the general contractor must give the homeowner a signed, city-provided form noting the availability and benefits of a full NFPA 13D-compliant sprinkler system. For land annexed to the City of Elgin after July 11, 2018, there is no basement-only option: the code requires a full fire sprinkler system installed to NFPA 13D, and that system must include backflow protection using a double check valve, unlike the pre-annexation basement systems.