The former "Home Improvement" star was spotted Tuesday for the first time since his Saturday morning bust in La Quinta, CA for allegedly driving under the influence ... and he stopped by two different watering holes in the same desert resort town, back to back.

First, Zachery went to the Amigos bar there around 3 PM yesterday ... plopping down at the bar for happy hour. There aren't any photos that explicitly show him sucking down drinks -- but it's a good bet that he probably might've been.

Now, we're told he stuck around for about an hour at Amigos before moving on to the next joint ... but he didn't drive on over -- he actually caught a rideshare this time.

Luckily, Zach played it safe on Tuesday ... responsibly grabbing an Uber to take him over to a local Applebee's, where he popped in and once again grabbed a chair at their bar.

Zachery again sat down ... and here, he was seen with a cold draft beer in front of him. He got to Applebee's around 4:15 PM, still prime time for happy hour by anyone's clock.

Obviously, him in this kind of setting is somewhat alarming -- especially when we know he was literally behind bars just a few days ago for allegedly drinking and driving. Yes, it's good that he's trying to be responsible by using Uber, but the fact he's in a boozy environment like this at all is troubling. Ya gotta wonder if everything's alright with him these days.

TMZ broke the story ... Bryan was arrested by La Quinta Police early Saturday morning for driving under the influence. He was also booked for misdemeanor contempt of court.

Cops say they conducted a traffic stop just past 2 AM after they saw a vehicle they suspected of being involved in a traffic collision. Police say they spoke with the driver -- later identified as Bryan -- who allegedly showed signs of impairment, leading to his arrest.