The draw moves Vancouver (7-6-13; 34 points) level on points with Portland in the race for the final playoff spot in the Western Conference, while DC (14-8-5; 47 points) increase their lead over Sporting KC to five points in the East.
Vancouver made more changes to their starting line-up and also their formation this week, going to a 4-4-2 diamond.
Right back Steven Beitashour hobbled out of training on Thursday and was replaced by South African Ethen Sampson, making his first MLS appearance. Kekuta Manneh dropped to the bench and Sebastian Fernandez came back into the starting line-up, this time as a striker to partner Darren Mattocks.
Vancouver took the game to DC early, with a very attacking line-up moving the ball about well without creating too many real chances.
Mattocks had a great chance to give Vancouver the lead 12 minutes in, having two attempts at finishing a cross into the six yard box, but ended up blasting high and over.
The game suddenly exploded into a chancefest in the final 15 minutes of the half.
Kendall Waston just failed to get his head onto a Pedro Morales free kick in the 31st minute, before Fabian Espindola had two great opportunities to give DC the lead.
The Argentine fired a fierce long range shot which David Ousted had to tip over in the 36th minute and followed that up by blasting over from the edge of the six yards box minutes later, when he only had Ousted to beat.
Mattocks finished the half by forcing two saves from Bill Hamid, but once again Vancouver couldn't take their chances and the teams went into the half scoreless.
The second half was a more cagey affair.
The Whitecaps threatened briefly at the start and Jordan Harvey came close with a flying header but that was it from either side until the 84th minute, when substitute Kekuta Manneh sent the ball across goal but Mattocks couldn't get on the end of it.
And that was it. Neither team looked like they were going to win the game, but Vancouver will be the ones most disappointed to just pick up a point.
FINAL SCORE: Vancouver Whitecaps 0 - 0 DC United
ATT: 18,116
VANCOUVER: David Ousted; Ethen Sampson (Sam Adekugbke 54), Andy O'Brien, Kendall Waston, Jordan Harvey; Matias Laba, Mauro Rosales (Mehdi Ballouchy 69), Russell Teibert, Pedro Morales; Sebastian Fernandez (Kekuta Manneh 69), Darren Mattocks [subs Not Used: Paolo Tornaghi, Nicolas Mezquida, Erik Hurtado, Omar Salgado]
DC: Bill Hamid; Sean Franklin, Bobby Boswell, Steve Birnbaum, Taylor Kemp; Nick DeLeon, Perry Kitchen, Davy Arnaud, David Estrada (Lewis Neal 70); Fabian Espindola, Luis Silva (Kyle Porter 84) [subs Not Used: Joe Willis, Kofi Opare, Alex Caskey, Jared Jeffrey]