Semrush’s Backlink Audit Tool features a toxicity score for certain types of backlinks. 

While it’s a helpful feature, the word toxic tends to put a bad taste in marketer’s mouths. 

After all, if some of your backlinks are showing up as toxic, shouldn’t you get rid of them as soon as possible?

Not necessarily. 

The reason why has to do with the 45+ toxicity markers that Semrush uses to calculate the score.

While some are actually markers of potentially harmful backlinks, others aren’t as cut and dry. 

As a result, sometimes high-quality backlinks that are actually helping your SEO will get labeled as toxic. 

Frightened to receive a penalty, this label causes some site owners to use Google’s Disavow Tool to cut all ties with the domain. 

Yet, Google’s Disavow Tool is complicated and can do serious harm to your search performance if you aren’t careful.  

For these reasons, you should take Semrush’s toxicity labels with a grain of salt (until you do further vetting). 

In this post, we’ll teach you everything you need to know about Semrush’s toxicity score, including how to spot truly toxic backlinks, so stay tuned! 

What are Toxic Backlinks, Anyway?

There’s a ton of confusion surrounding the term ‘toxic backlinks.’ 

Formally defined, a toxic backlink is any backlink that has the potential to harm your search performance through penalties. 

The thing is, there are very few types of backlinks that truly qualify as toxic. 

A common misconception is that backlinks coming from spammy websites with low domain authority scores are toxic. 

This is not true because low-quality backlinks don’t impact your SEO at all. 

Google’s algorithm simply ignores them. 

By that, we mean it doesn’t assign any value to those types of links. 

For proof, check out this post from John Mueller (it’s from a while ago, but this debate has been going on for years):

As you can see, he states that Google ignores backlinks coming from spammy domains, so you don’t need to use the Disavow tool (or do anything at all, really). 

In this quote, he even claims that Google has no notion of ‘toxic’ backlinks:

Here, he only recommends disavowing backlinks that you intentionally purchased, which violates Google’s search guidelines. 

That brings us to our main point:

The only truly ‘toxic’ backlinks are ones that directly violate Google’s search guidelines. 

Examples of truly toxic backlinks

These are the types of backlinks that can cause a manual penalty from Google:

  • Spammy anchor text links. Google pays attention to the anchor text your backlinks use, and using the same anchor text over and over (like using a keyword) is a sign you’re trying to manipulate the rankings. Check out our guide on anchor text ratios to learn more. 
  • Paid backlinks from link farms and PBNs. Google does not want websites paying for backlinks, especially ones coming from link farms and private blog networks (PBNs). However, buying backlinks is a common SEO practice, despite the risks. Our guide on buying backlinks will teach you how to go about it the safe way. 
  • Widget backlinks. Sometimes, site owners will hide backlinks inside widgets that are distributed across various websites. These types of backlinks qualify as link spam according to Google. 
  • Excessive link exchanges. Google views two websites frequently linking to each other as a link scheme. 

Check out Google’s spam policies to see the complete list. 

Notice something in common here?

All of these techniques require your direct participation. 

This means that if there are toxic backlinks pointing to your site, you’ll know about them. 

Probably the biggest myth surrounding ‘toxic’ backlinks is that they can accumulate without you knowing about it. 

The fear is that one day your site will suddenly have dozens (or hundreds) of toxic backlinks pointing at it, wrecking your SEO and forcing you to spend hours disavowing them. 

This type of nightmare situation does not happen. 

As this Redditor sharply points out, if spammy backlinks harmed a website’s SEO, competitors could use it to their advantage:

So, unless you intentionally took part in link schemes, you likely won’t have any toxic backlinks at all. 

Unpacking Semrush’s Toxicity Score 

Now that you know the truth about ‘toxic’ backlinks, let’s take a closer look at Semrush’s Toxicity Score. 

Is it a completely bogus score that isn’t helpful?

No! 

In fact, as mentioned in the intro, many of its toxicity markers are accurate. 

Let’s take a look at a few so you can see what we’re talking about. 

On this page, Semrush lists all the toxicity markers it uses to calculate the score. 

For instance, these toxicity markers indicate the presence of link networks (PBNs and link farms), which we already mentioned are indeed toxic:

There are also markers to indicate anchor text spam:

So, what’s the issue, then?

Problems start to arise with some of its Harmful Environment toxicity markers:

Here, they include things like HTTP status codes and dropped positions as toxicity markers. 

While no one likes having a broken backlink (like a 404 not found), it’s definitely not toxic. 

Instead of panicking and disavowing a broken backlink, you could reach out to the site owner to get it restored (or add a link to a new page). 

Also, a website dropping a few positions on Google could mean they were simply outdone by competitors instead of violating any search guidelines. Once again, disavowing these types of backlinks would likely be a mistake. 

The point is that there are numerous toxicity markers that can mistakenly flag high-authority websites that are simply experiencing a few issues (like some broken links or a temporary drop in rankings). 

Final Thoughts: Semrush’s Toxicity Score 

Semrush’s Backlink Audit Tool is definitely useful, as are all of the platform’s SEO offerings. 

However, the Toxicity Score has the potential to confuse and panic users who aren’t familiar with its intricacies. 

Our recommendation?

Don’t panic unless you know for a fact that you built manipulative backlinks. If you did, disavow those, and ignore the rest! 

Do you want our expert team to analyze the strength of your backlink profile?

Book a free strategy call with us to make it happen!