The promising 20-year old, who made 28 appearances for the Washington club this season, will train with the Baggies for an informal stint from Monday and is looking forward to improving his game.
"It's a good opportunity to train and get better, take in the Premier League atmosphere," Hamid said. "I'm just going to work hard."
Hamid is still under contract at DC but his agent Chris Megaloudis says it was a great opportunity which United have given their blessing to.
"The opportunity presented itself," he said. "It's good for everyone.
"Someday Bill will have an opportunity to play overseas and this is a chance for him to see what it's like and for clubs to get to know him."