No. Child support payments are not subject to tax. Previously deductible, alimony payments no longer qualify as tax deductions as a result of the bill's passage.How do I apply for Child Support Services? You can complete the application at your local CSS office or apply online. Child support is never deductible and isn't considered income. AFFIDAVIT OF: Plaintiff. Defendant. Child Support Services (CSS) are available to anyone who needs help collecting child support through a network of state and locally run offices. One of the most commonly required forms is the Affidavit of Financial Standing or Financial Affidavit. If you are curious about how your income will be calculated and used to make decisions regarding child support and alimony payments, learn more below. Both spouses will typically have to complete a full financial disclosure as part of the divorce process.