Mayor Bill de Blasio said on Wednesday that he was going to add $305 million to New York City’s capital budget to speed up work on Water Tunnel No. 3 so that it would be able to serve Brooklyn and Queens.

The money will pay for construction of two deep shafts in Maspeth, Queens, that will connect with the tunnel, which is virtually finished. When the work is done, the five million people who live in the two boroughs will have a robust supply of water other than Tunnel No. 2, which was built in 1936.

The mayor’s announcement came just hours after The New York Times reported that his administration last year had removed all money to pay for the tunnel and had also replaced the announced 2021 deadline for completion with a commissioner’s “guess” that it would be ready for service sometime in the mid-2020s.

Those actions and statements, the mayor said, had been misunderstood as postponing the work. “There are times when my team does not do a good job of explaining something,” he said.