In a Google Webmaster Hangout in March 2017, Google’s John Mueller was asked the question:
“Can low quality pages on a site affect the overall authority?”
In response, John answered with the following:
Yes… in general when our algorithms look at a website overall, they do look at individual pages as well. If there are a bunch of really low quality, bad pages on a site. Then that does affect how we view a site overall.
On the other hand if it’s a really large website and there’s a handful of pages which are kind of bad, then we also understand that in the bigger scheme of things that those pages aren’t the main issue for this website.
If you’re aware of low quality pages on your website then that is something I’d try to fix and find a solution. So either removing those pages if you really cannot change them, or in the best case finding a way to make them less low quality, and make them useful pages on your site.
This advice, whilst not surprising if Google are thinking of user experiences, is fairly conclusive.