MuchMoreThanMuscle saidCash pretty much nailed it.
Now for every quart of water I drink I add an 1/8 of a teaspoon of iodized salt to my water. I notice a difference and feel a lot better.
On average, most people consume way more sodium than what's recommended. Many of these are not able to properly regulate their sodium balance and will accumulate it, leading to water retention and quite often high blood pressure. Since hypertension has numerous effects on your health, just check your blood pressure now and then and make sure it's within the normal limits (<120/<80 is ideal, but a bit higher is normal). If it's considerably higher though, speak to your GP. Reducing sodium intake would be the first thing to do.