I moved my plants and put down a few floor tiles. They went under the puddle. I then had a sim mop the floor, and I then deleted the tiles and moved the plants back to where I wanted them.
Sims with the neat trait can mop the outdoor puddles, too. If your sim has a neat acquaintance, invite them over and after talking to them breifly, leave them alone and they might clean up for you. My sims have had neat guests clean counters, clean spoiled food out of the fridge, and scrub the toilet.