WASHINGTON, July 14 (Reuters) - A sweeping overhaul of the U.S. healthcare system to be announced on Tuesday in the U.S. House of Representatives will include a surtax on millionaires of 5.4 percent, congressional sources said.

The tax rate is higher than the 3 percent surtax lawmakers had been discussing earlier and would be imposed on those making more than $1 million a year, the sources said.