Islamorada Transmission Main Replacement Project

One of our most important projects to-date has begun in Islamorada. 

Meet Precious, our modern marvel system mascot. She will be with you every step of the way to explain the project details and provide updates as they become available. When you see Precious, you know innovation is in progress!


What are we doing? 

In April 2023, we began installing a new transmission main to replace the existing, original main that’s approximately 40-years-old.

Click here for more info on the Islamorada Transmission Main Replacement Project Work Plan.

What’s a transmission main? 

The transmission main carries your drinking water from the water treatment plant to your faucet.

Why does it have to be replaced? 

Because clean drinking water is a MUST. As pipes age, they become more susceptible to corrosion, leaks, storm surge, and other effects.

Why is this project a modern marvel? 

Get ready, we are about to geek out here. 

The new, 36-inch diameter cathodically protected steel water main will be installed via open-cut trench installation. Cathodically protected means the pipe will be protected from corrosion. In the keys we have aggressive soils and subterranean tidal flows that submerge and expose the pipeline to corrosive conditions, and this will ensure the pipe’s not compromised. 

The project also includes connection to existing mains and master taps. New transmission mains will also be installed at the Teatable Relief and Whale Harbor bridge crossings via horizontal directional drill (HDD). This means the transmission main will be underwater, so it will be protected from high winds and storm surges.

Where is the new transmission main going? 

The new transmission main is approximately four miles long. It will begin near MM 79.5 and continue north along US-1 in Islamorada to just south of Whale Harbor Channel near MM 84.

What traffic impacts are expected?

Crews will be working 24/7 Monday through Friday. 

  • One northbound and one southbound lane will remain open along US 1 for the duration of the project.
  • The bayside portion of the Heritage Trail will be closed, but a crosswalk to the ocean side of the trail will be maintained through March 2024.
  • Bike lanes will remain accessible.

When will the project be completed?

The project will be completed in February 2025 however traffic impacts are expected to lessen after March 2024.

How much will this project cost?

The Islamorada transmission main replacement project will cost approximately $42 million, with $35 million funded by grants and $7 million funded through low-interest loans.