Major Water‑main Break at MM 91 Floods U.S. 1, Slows Traffic

A major water main failure at mile marker 91 in Tavernier sent water spilling across Old Highway and U.S. 1, slowing northbound and southbound traffic and producing localized flooding on the roadway, the Monroe County Sheriff’s Office said. Lane restrictions were in place as crews and first responders worked to keep traffic moving.

The Miami Herald's David Goodhue reported the break occurred "around 11:30 a.m. Saturday" during late-morning traffic on Feb. 21, 2026. KeysNews described the Florida Keys Aqueduct Authority's water main as having ruptured late Saturday morning near MM 91, just north of where FKAA has been conducting a pipeline replacement project, and said the break was spilling water onto the highway as repairs began.

FKAA began on-site repair work Saturday afternoon, and KeysNews reported that FKAA posted Sunday: "Repairs were made to the 30-inch main. A back pump operation was completed and the water main was restored to normal flow at 12:30 a.m." KeysNews also advised that "Motorists were advised to use caution." The KeysNews post does not specify the calendar date tied to the 12:30 a.m. timestamp.

The ruptured pipe is identified in local reports as a 30-inch main; the FKAA replacement program in the area has been installing 36-inch-diameter steel pipes since 2023. KeysWeekly traces that replacement work from Tea Table Relief at MM 79.5 northward, noting crews placed more than 10 miles of new transmission main in the last three years and that "each mile of new pipe costs $10 million." Construction-related traffic controls already in place in the Tavernier corridor included a one-lane shutdown between the southern end of Tavernier Creek Bridge and Ocean Boulevard, posted speeds of 35 mph through the work zone, and scheduled left-turn blocks and flagger/police assistance at plaza exits during overnight windows.

The rupture occurred about 4 miles north of Founders Park, where the Upper Keys Rotary Club was holding its Giant Nautical Flea Market Saturday and Sunday; KeysNews noted that the annual event "slows traffic through Islamorada," compounding congestion in the Upper Keys during the weekend incident. The Monroe County Sheriff's Office confirmation that both northbound and southbound travel on U.S. 1 was affected came as FKAA crews worked to clear water and restore the line.

Several key details remain unreported by agencies: no source so far has said whether potable water customers experienced service interruptions or boil-water advisories, and no official cause for the pipe rupture has been provided. Local officials have not reported injuries or property damage in available accounts. The incident spotlights the scale of FKAA's multimillion-dollar replacement effort and leaves outstanding questions about cause, customer impacts, and any effect on the project schedule that FKAA and Monroe County have not yet addressed.