A penalty goal was the only difference between the two sides on Saturday.
Adam Moffat was the man responsible for giving away the penalty, rolling under Olmes García in the 36th minute and gifting RSL a chance to take the lead.
Alvaro Saborio made no mistake from the spot, and Salt Lake took the 1-0 lead into the break.
Houston had a few chances to climb back level in the second half, but RSL held firm and took all three points.
With the win RSL climbs four points clear at the top of the West.