Yes, sodium will have a HUGE impact on water retention. You can choose to ignore it if you want, since you can burn fat just fine while retaining water, but since most people like to see results on the scale, you might want to keep an eye on it. It's not just putting table salt on foods, either... deli meat, canned and frozen food, restaurant food, and alcohol can all have a big effect on water retention. It drives me nuts.

I've been very careful about sodium and drinking plenty of water for the past 5 days, and the plateau I've been on for the last 3 weeks is just vanishing, I've lost 3 pounds of water weight in the last 5 days. Instead of salting my food, I've been using AlsoSalt (butter flavored) on things like broccoli and baked potatoes. It's not as good as the nice kosher salt I was using, but it's better than nothing while I work on getting all this weight (water and fat!) off.