A burst water main caused flooding Tuesday afternoon on a portion of the eastbound Bay Bridge inside the Treasure Island Tunnel, leading to the brief closure of two traffic lanes.The California Pacific Highway Patrol posted on X at 1:43 pm Tuesday that a water main had ruptured inside the Treasure I sland tunnel above eastbound I-80. Eastbound lanes four and five were closed to traffic due to flooding.***TRAFFIC ALERT on I-80 e/b***Due to water main break above, the #4 5 traffic lanes of I-80 e/b (SF/Oakland Bay Bridge) in the Treasure Island tunnel are temporarily closed due to flooding. Caltrans SF Fire are currently on-scene attempting to resolve the incident. pic.twitter.com/Oefx5VkWmy— CHP San Francisco (@CHPSanFrancisco) April 21, 2026 Crews from Caltrans and the San Francisco Fire Department responded to the scene, and all lanes were re-opened 45 minutes later.Drivers were advised to still use caution when driving through the tunnel.The post was updated with the correct day — Tuesday. Apologies for the confusion.Image: CHP/X ...read more read less