John Mueller recently discussed on Google + about having spaces in your URL’s. This usually happens when we create blog posts and did not check on the URL’s created by our favorite CMS. Most of the time, we see something like %20 within the URL’s.
According to John:
(the answer is not “no” :-)) I run into this question every now and then, maybe this will help someone get it right too :).
TL;DR: use “+” or “%20” in the query-string, use “%20” within the rest of the URL.
His answer as usual is a bit confusing but just to be safe, lets just make sure we review our URL’s and make sure there were no spaces and just use hyphens.