Our state tax is 3.23% and our county tax is 2.9% Employees at hubby's company who were already working there when they signed up with ADP had county tax taken out. Anyone added later did not and now are having to pay at the year end. Is ADP liable for this tax since they didn't make sure it was being taken out?
ADP is not generally reponsible for employee tax withholdings. ADP is a payroll services suite for automating parts of the payroll process. The responsibility is on the actual employer for properly withholding payroll taxes, since it's the payroll administrator on the employer side who will set up your tax information on ADP using your form W-4, information about your state, and your locality. It would be a fault on ADP if you (1) discovered that the service was somehow malfunctioning, and failed to withhold taxes despite current good settings, or (2) if you were employed by ADP, or ADP served as employer of record (they handle personnel issues e.g. manage your withholdings, like an employer would, while you work elsewhere. Check the EIN or tax registration code for the company on your W-2).
Also consider that it's partly on the employee to ensure that applicable payroll taxes are being appropriately withheld. For example, you direct your employer to how they will withhold your federal income taxes with form W-4, but it's not the employers responsibility to verify the amount being withheld will be commensurate with your annual tax burden.
Speak to your employer about rectifying the withholding issue, and if necessary, a lawyer about the next steps to take. Bear in mind that you're still liable for whatever tax burden exists, whether your employer withholds it or not. The employer will generally be liable for whatever penalties result from failing to withhold the taxes.