<p>Seemingly the remaining water becomes impure and may not be used.</p>
<hr class="shulchan-footnotes-sep"><section class="shulchan-footnotes"><div class="shulchan-footnotes-body"><ol><li id="shulchan-fn-1">Based on Halacha B see there! <a class="shulchan-fn-back" href="#shulchan-fnref-1" aria-label="Back to text">↩</a></li></ol></div></section>

Shulchan Aruch HaRav | What is the law if after the first pouring some of the water on one’s hand fell into the remaining water in the cup?

Seemingly the remaining water becomes impure and may not be used.