I believe this information was pulled from the county tax records for this home, so if it isn't correct, perhaps the county has your home recorded improperly. I'd start there.
Also, I couldn't see that this property is listed at all. Do you plan on selling or were you just checking around? I'd be happy to help you discuss this further if you're interested.
Best of luck with any of your future decisions!
Windermere Real Estate/Bellevue Commons, Inc.
1200 112th Avenue NE Suite B100
Bellevue, Washington 98004
Direct 425-450-2601 Fax 425-450-2600
Your home is not on the market. Trulia receives their data from public records, which don't currently reflect the 4th bedroom.
Sites like this and Zillow are only as good as the data they access. If you want these sites to more accurately reflect your homes characteristics, you might want to update King County Records. Of course this could have a tax consequence, so proceed carefully.
No algorithm or formula can reliably interpret the real facts of the market, both in terms of what a home actually offers in room count and condition to where the buying public is reacting to.
If you are looking to obtain a more reliable valuation, feel free to contact me or most local agents who work in the area and tour the homes regularly. We'd love the chance to help.