Property tax appeal. What are basis for an appeal?

How do ya do it?

Do ya need a lawyer.

What are valid reasons for an appeal to succeed?

You don't need a lawyer. Start by requesting a copy of your property's record card so you can see if there are any errors in basic factors like square footage and number of bedrooms considered in arriving at your property's real property assessment .  If the record card is inaccurate, that would be one basis for appeal. The other basis would be to examine the comps that were used in determining your property's real property assessment. These vary by assessment neighborhood.  If these were applied incorrectly you would also have possible grounds for an appeal.  In your case, you should take a look at the percentage of increase in real property value in your assessment neighborhood.  If your real property assessment increase is in keeping with pattern, you have less of a chance of a successful appeal since that would tend to indicate that the comps were applied uniformly.

https://maplewood.worldwebs.com/reval/  Should have much of the raw data you would need to examine in order to determine if you have a reasonable chance of winning a real property tax appeal.