I decided to check just how much possible sqft exaggeration is out there and the results are shocking. The first two I checked had huge differences in sqft so I decided to check more.
Just a few examples:
https://www.redfin.com/CA/Irvine/27-Sonrisa-92620/home/4785645 - listed at 3,500 Sq. Ft.
Redfin Public Records Total Sq. Ft. - 2,963
Trulia Public Records Total Sq. Ft. - 3,241
http://www.trulia.com/property/3242333793-39-Bamboo-Irvine-CA-92620- listed at 2,500 sqft
Trulia Public Records Total Sq. Ft. - 2,416 sqft
http://www.trulia.com/property/1039975504-2-Brisa-Irvine-CA-92620- listed at 2,102 sqft
Trulia Public Records Total Sq. Ft. - 1,979 sqft
https://www.redfin.com/CA/Irvine/3-Revere-92620/home/4778410- listed at 2,951 sqft
Redfin Public Records Total Sq. Ft. - 2,391 sqft
Trulia Public Records Total Sq. Ft. - 2,951 sqft
http://www.trulia.com/property/3241177552-29-Cedarbrook-Irvine-CA-92620- listed at 3,000 sqft
Trulia Public Records Total Sq. Ft. - 2,643 sqft
http://www.trulia.com/property/3054050405-3-Morro-Bay-Irvine-CA-92602- listed at 4,404 sqft
Trulia Public Records Total Sq. Ft. - 4,358 sqft
http://www.trulia.com/property/3239631848-81-Legacy-Way-Irvine-CA-92602- listed at 3,700 sqft
Trulia Public Records Total Sq. Ft. - 3,748 sqft
https://www.redfin.com/CA/Irvine/83-Pinewood-92604/unit-42/home/5476188- listed at 2,016 sqft
Redfin Public Records Total Sq. Ft. - 1,911 sqft
http://www.trulia.com/property/3242547333-5-Lakefront-Irvine-CA-92604- listed at 1,923 sqft
Trulia Public Records Total Sq. Ft. - 1,986 sqft
http://www.trulia.com/property/3242699395-16607-Mosscreek-St-Tustin-CA-92782- listed at 3,137 sqft
Trulia Public Records Total Sq. Ft. - 3,198 sqft
http://www.trulia.com/property/6008737-4551-Sandburg-Way-Irvine-CA-92612- listed at 3,200 sqft
Trulia Public Records Total Sq. Ft. - 2,682 sqft
https://www.redfin.com/CA/Santa-Ana/11601-Las-Luces-92705/home/4762534- listed at 4,700 sqft
Redfin Public Records Total Sq. Ft. - 3,404 sqft
Trulia Public Records Total Sq. Ft. - 4,641 sqft
http://www.trulia.com/property/3155564021-151-Desert-Bloom-Irvine-CA-92618- listed at 1,900 sqft
Trulia Public Records Total Sq. Ft. - 1,900 sqft
https://www.villagesofirvine.com/villages-neighborhoods/portola-springs/sage/residence-2/- Residence 2 1,878 Sq. Ft
About 40% of the listings didn't have the public records match listing records. Of the ones that didn't match only 3 had public records sqft barely larger than listing while there were 9 with public records less than listing sometimes by more than 500 sqft. The last one I knew had to be off since it seemed to rounded up to the nearest hundred. 22 square feet is a lot! That's a walk-in pantry or a small mud room!