Yes it is, and that salt is good for your plants. Here's the thing, most tap water is fine to grow with but many people have let others convince them that it's not. The simple fact is, most nute lines are formulated to use with tap water because that's what most people use. Many people use R.O. water and take out the salts and what do they do? The cal-mag cha-cha-cha, they put it back in by buying another product at their local hydro store (who told you tap wasn't good?)
So about 90% of the tap water out there is fine to grow with, the best way to check is by doing a grow. You can buy meters and all type of crap to test your water, but just doing a grow will also.
If your water is really really really bad, then you'll have to filter it.
Here's another bit of info they don't tell you, since your tap water's pH is 7.0 there is a good chance your pH will be perfect after adding nutes without adjusting.