Yes, you shall not wash your contact lenses with tap water. Tap water usually contain some bacterial that we can't see. Your contact lenses my get the bacterial in tap water. However, unlike eyeglasses, contact lenses can directly contact our eyes, it is likely cause eye infection if there is bacterial on the contact lenses. This is the reason why contact lenses are required to to be clean with contact solution. So, you shall buy a bottle of contact lenses solution when you buy contacts for the sake of your eyes. Even if you don't wear your contact lenses, you still require to wash your contact lenses with contact solution at least 3 days a time.