Kelyn Rowe scored in the 63rd minute and Raul Ruidiaz added a second in the fourth minute of stoppage time as the Sounders set the league record for most consecutive games unbeaten at 13.
Story of the match
Seattle was on the front foot early on and in the seventh minute, Ruidiaz got behind the Houston backline, but his shot from inside the box hit the bottom corner of the far post.
The Dynamo tested Sounders goalkeeper Stefan Cleveland in the 17th minute as Maxi Urruti played a neat one-two with Memo Rodriguez, passing it to the American and his shot from just outside the box was handled by Cleveland.
Just two minutes later, he was caught off his line as the visitors looked to take advantage, but Fafa Picault saw his effort blocked by Abdoulaye Cissoko. At the other end, Marko Maric saved at the near post from Fredy Montero.
A cross from Jimmy Medranda found Montero for a free header that was right into the arms of Maric. Medranda then timed another cross, this one to Ruidiaz, but he went wide as the Sounders continued to keep up the pressure.
Picault forced a clearance seven minutes from halftime when his cross skipped across the face of goal and past two Seattle defenders, the last meaningful action of the first half.
The Sounders finally broke the deadlock in the 63rd minute as Montero sent a long cross to Alex Roldan, who controlled a deflected ball and crossed for Rowe, who re-directed with his left foot past Maric to give the hosts a 1-0 lead.
Houston had their best chance to level in the 89th minute as Urruti's long-range effort was easily handled by Cleveland. Brad Smith then made a scintillating run and crossed for Ruidiaz, who finished and secured victory and history for Seattle.
Man of the Match: Jimmy Medranda
While Rowe and Ruidiaz grabbed the goals, it was Medranda who controlled much of the action for Seattle and he very well could have registered a pair of assists before coming off.
Sounders stand alone
Tied with four other teams for the longest unbeaten start to a season, Seattle set the record with a performance that is typical of their play this season. They controlled play, put pressure on their opponents and eventually struck. The way they are playing, the streak is not likely to end anytime soon.
Rowe's dream night
After signing for his hometown club in January, the Federal Way native finally had his moment, scoring his first goal in a Rave Green jersey in front of the Brougham End, delivering a moment that he nor anyone associated with the Sounders won't soon forget.