SOL on Taxes?

Does anyone know if there is an exception for taxes, regarding statutes of limitation? I owe $325 to my local school district for an occupational tax. This is from 1999. I live in PA. I had gotten this off of my credit report a few years ago (I actually had no knowledge of the debt then) and just found out that it is back!

It’s so old, it won’t really make much of a difference on my credit report/score. What should I do?

Thanks in advance!