The East Bay Municipal Utility District, which provides water to 1.3 million customers around Berkeley and Oakland in California, will lead municipal borrowers today with a $400 million Build America bond sale. The utility, which plans to offer 30-year bonds, is rated Aa2 by Moody’s Investors Service and AA by Fitch Ratings, each the third-highest rank, and AAA by Standard & Poor’s, the top grade. Hawaii and the Las Vegas airport previously this week sold almost $1 billion in Build America Bonds, whose taxable interest costs are 35 percent federally subsidized.