JSFiddle - React, Tailwind, and code Playground
HTML
<a href="https://yourwater.oregon.gov/dcoliform.php?pwsno=" target="_blank" id="DataOnline">Data Online</a>
<input type="text" id="PWS" value="99999" />
JavaScript
var hreftxt = $("#DataOnline").attr("href");
$("#DataOnline").attr("href", hreftxt + $('#PWS').val());