Puddle & Pedestrian Etiquette

Okay, I'm going to claim ignorance on this one. It was raining this morning as I drove to work. I was driving the speed limit down a 35-mph street when suddenly I hit a puddle along the right side of the road, sending a large spray of water up on the sidewalk. Unfortunately, a pedestrian was walking along the road and got drenched by the spray from my car. It was unavoidable as there was a car to my left in the inside lane preventing me from swerving around it. I wasn't in a position where I could stop and offer some help to the guy, as there was no shoulder on the road. I could see him in my rear-view mirror mouthing profanities and waving one of his fingers angrily in my direction. I felt bad, and I wonder what I could have done differently. Because I've always lived in the suburbs and rarely drive downtown, I'm ignorant as to the unwritten rules of the road when approaching stagnant water on the road when podestrians are near. Are drivers supposed to slam on their brakes to try and lessen the amount of water splashed? In my opinion, both drivers and walkers share the responsibility of preventing such mishaps, but pedestrians especially have more time to see oncoming puddles and can walk around any potentially drenching danger. I'm asking the world, especially those of you who live in big cities, to set the record straight.