You are supposed to be able to "Edit Home Facts" on the information page for your property. I have tried it on my own property, Trulia sends me a link to verify my email, but their system appears to be broken. I have opened several tickets with them, which they never responded to. Later, I opened a ticket on Zillow about Trulia and they responded but didn't fix anything. If the data is coming from the County Assessor, you can call them and request to amend it. They may or may not send someone out to verify and it could take months for the data to eventually get corrected on Trulia and everywhere else. A Realtor can help. Good luck!