The Answer is No! If below are present...
Phosphates, nitrates, and silicates are elements that naturally occur in water, and it is not unusual for some tap water sources to contain high concentrations of these chemical elements. If these are not removed from the water before using it, you are just adding more of the unwanted elements that give rise to all types of algae blooms in saltwater systems, and that often contribute to persistent problems with higher than normal readings of these chemicals when testing the aquarium water.
Copper and iron are particularly detrimental to reef animals, and these or other metals can often be present in tap water as well. Also, Chlorine kills fish.
So what can one do to ensure the freshwater supply that is being used is of the best and safest quality? There is no guarantee that even if you filter the tap water first, problems won't arise. The simplest solution is to learn all about the many methods one has to choose from to purify tap water, or use an alternative water source.