Zillow touts itself as the go-to source of information for homes for sale (along with Trulia, owned by Zillow). Beware, though, that Zillow’s listing data is not as up-to-date as it should or could be. If you search the web, you’ll find some articles and blog posts on this.

I’ve just experienced this problem with Zillow (again), this time with the house I recently listed for sale at 2612 Bowling Green Drive, Vienna, VA. I thought I’d share the details, so you can see what I’m talking about…

Early in the morning on Monday, April 11, I entered the house for sale into the multiple listing service that all realtors in the DC area use (Metropolitan Regional Information System or “MRIS”). In the MRIS system, I also entered an open house for Sunday, April 17.

For the DC area, all listing information that Zillow and other real estate websites display ultimately comes from the MRIS database. By the afternoon of April 11, the listing and open house information for 2612 Bowling Green Drive had propagated from MRIS’s database to many of the websites that list houses for sale, but not Zillow.

Late in the evening on Tuesday, April 12, Zillow finally began displaying the listing and open house information for 2612 Bowling Green Drive.

This is consistent with what I’ve long suspected: Zillow’s employs a not expeditious two-level process whereby 1) once each day, Zillow obtains new listings from each of the many multiple listing services across the country, and 2) once each day, Zillow updates the live database from which listings are served up onto their website. If indeed the case, it may take at least 24 hours, and as many as 48 hours, for a new listing to show up on Zillow’s website. That’s a significant delay, especially if the market is strong and houses are selling quickly.

The house was under contract quickly. Mid-afternoon on Wednesday, April 13, in the MRIS system, I changed the status for the listing to “under contract” (which translates to “pending” on Zillow and other websites). I also deleted the open house that I had previously scheduled, since that would no longer be necessary.

FOUR DAYS LATER, on Sunday, April 17, Zillow still showed the house as “for sale” (not “pending”) AND the open house as still scheduled! Evidently, Zillow does a poor job of accounting for changes made to existing listings. That afternoon, I received calls from several people who had arrived at the property expecting an open house, based on Zillow’s out-of-date information.

Long story short: If up-to-date listing and open house information is important to you in your home search, Zillow should not, unfortunately, be counted on.

Update on 5/1/16: It’s now 18 DAYS after I changed the house’s status to under contract in the MRIS database and Zillow still shows it as “for sale” (not “pending”)! Clearly, Zillow’s approach to keeping its data up-to-date, whatever it may be, is seriously flawed. I sent an email to Zillow on 4/17/16 alerting them to the error in this case but never received any response.