Bring water to a boil in medium saucepan, add potatoes. Remove from heat, let ... stir together mayonnaise, sour cream, relish, mustard, horseradish, salt ... 6 to 8 servings.
Boil potatoes until just barely done. Allow to cool completely. Combine mayonnaise, sour cream, relish, mustard, dill, salt ... while potatoes are cooling.