Fitchburg, WI Building Safety: Fire Sprinkler Requirements (2026)

Section 44-528(3) sets the residential sprinkler thresholds by building size rather than by a single blanket rule. New multi-family dwellings, apartment buildings, townhouses, condominiums, hotels, motels, dormitories, fraternities, and sorority houses (any place of abode except a one- or two-family dwelling) fall under it. A new residential building with three interior stories or less, or no more than four living units, only needs sprinklers in its basements, crawl spaces, stairways, and corridors. Once a building exceeds three stories or holds more than four living units, it must be protected by an automatic sprinkler system throughout, regardless of construction type.

One- and two-family dwellings are carved out of the mandate entirely: section 44-528(3)(b) and the exceptions list in section 44-529(3) both confirm sprinklers are not required in one- and two-family homes. But the exemption is not a free pass if an owner chooses to install one anyway. Section 44-528(3)(b)(1) requires any sprinkler system voluntarily installed in a one- or two-family dwelling to meet NFPA 13D, the standard written specifically for one- and two-family dwellings and mobile homes, and section 44-525 repeats that split, sending everything else to the stricter commercial NFPA 13 standard.

Section 44-530 adds a fallback for smaller buildings in areas without municipal water: they must be built to structurally support a sprinkler system, with 90 days to actually install one once municipal water becomes available.