Real estate data site Zillow (Z) filed a patent infringement suit against Trulia this week, claiming its chief competitor infringed on an existing patent that fuels the website's ability to provide up-to-date real estate estimates to users. 

Zillow launched the suit in a U.S. District Court in Seattle, claiming it obtained a specific patent on a series of processes that allows its online platform to give users accurate home valuations. Specifically, Zillow says its 'Zestimate' home valuations are known for being more accurate since the systems in play allow parties linked to the properties to submit updated data online to inform the valuations. 

The patent filed with the U.S. Patent and Trademark Office is titled "Automatically Determining a Current Value User, Such As Its Owner."

Zillow claims Trulia, an online competitor in the real estate data business, launched Trulia Estimates in September 2011, allowing users for the first time to provide input from homeowners to improve the accuracy of real estate estimates provided by the site.

Zillow claims its patent, which describes the process of allowing informed users to improve valuations, is the structure informing Trulia's estimates.

A spokesperson for Trulia said Thursday the company cannot comment on pending litigation.

Zillow's legal team filed a complaint requesting a jury trial on the grounds that "Trulia's (alleged) acts of infringement have caused damage to Zillow, and Zillow is entitled to recover from Trulia the damages sustained by Zillow."

kpanchuk@housingwire.com