How long does Google take to reduce the index size?

[cplastiras84]

A few months ago, we have incorporated our custom search in our website www.ergodotisi.com . We hadn't been paying a lot of attention to our webmaster analytics, to find out a few months later than the Google Index had grown from 2K- 3K pages to one million because it was crawling all combinations of search filters. We have now followed the right instructions to add noindex meta tags and blocked most search result pages from the robot.txt. We allow indexing of some main categories by setting new seo-friendly url structures. A few weeks have passed and the index size has only reduced to 700K. How long does it take before it removes most of the duplicated search result pages from the index? Is it still crawling those pages but has not fully decided to remove most of them? How bad is this for SEO?

[GastonRiera]

Hello there,

Did you left some time, without blocking those pages, to google bot to recrawl them?

If you implemented at the same time the noindex tag and the disallow in the robots.txt you are not letting google know that those pages should be deindexed.
Remember that blocking pages in the robots.txt avoid to be scanned again and the new robots tag is not seeng by google bot.

My advise is to let google bot recrawl all those pages and wait a few days, may be 2-3 weeks. Slowly the amount of indexed pages will decrease.

Hope i've helped.
Best luck.
GR.

[DonnaDuncan]

How long does it take before it removes most of the duplicated search result pages from the index?

Every site is different but I have seen it take 6 - 9 months for pages to drop out.

Is it still crawling those pages but has not fully decided to remove most of them?

It's possible. As Gaston has already pointed out, search engines will need to access those files again to see you want them noindexed.

How bad is this for SEO?

It temporarily dilutes the amount of SEO equity available to flow to pages you DO want indexed.