Once you request the removal of a URL, Google says that it might continue to stay for at least 90 days, although, it will not be displayed in the Google search results. During the 90 days span, which is seen as a temporary period, you can withdraw your request for removal. If withdrawn, the company will display the page in their search results after the 90 days period.

Complete removal

To completely remove a URL, Google says that site owners must ensure the implementation one of the page blocking methods (for the URL of the page that they want removed) listed below:

• indicate that the page no longer exists by returning a 404 or 410 HTTP status code
• block the page from crawling via a robots.txt file
• block the page from indexing via a noindex meta tag

Following one of these three steps will ensure that the URL is removed for good from Google's search results as long as the page is blocked. In case a site owner removes the blocking method applied to the URL (which have been removed from Google's search results), the company says that they "may potentially re-crawl and index the page." For an immediate and permanent removal, "you can request that a page be removed using the Remove URL tool and then permanently block the page's URL before the 90-day expiration of the removal request."

If you want more information on URL removal, there is a blog series on the same. You can also raise questions regarding this latest change or URL removal at Google's Webmaster Help Forum.