Do I have to file CT-State Tax if my 1099-INT is under $6000.00? Does form SSA-1099 Social security benefit statement count as gross income toward filing State Tax?

It depends on the social security amount. Half of social security plus the other income minus the base amount to determine if taxable. If she is filing a federal return and has taxable social security, then it goes into the gross income test. Otherwise, it does not.

Even if it is taxable, it would have to be at least $9,000 taxable with the interest to hit the filing mark for a single. See this  calculator to determine if it is taxable.

Gross Income Test

Gross income means all income you received in the form of money, goods, property, services not exempt from federal income tax, and any additions to income required to be reported on Form CT‑1040, Schedule 1.

Gross income includes income from all sources within Connecticut and outside of Connecticut. Gross income includes but is not limited to:

• Compensation for services, including wages, fees, commissions, taxable fringe benefits, and similar items;
• Gross income from a business;
• Capital gains;
• Interest and dividends;
• Gross rental income;
• Gambling winnings;
• Alimony;
• Taxable pensions and annuities;
• Prizes and awards;
• Your share of income from partnerships, S corporations, estates, or trusts;
• IRA distributions;
• Unemployment compensation;
• Federally taxable Social Security benefits; and
• Federally taxable disability benefits.

You must file a Connecticut income tax return if your gross income for the 2023 taxable year exceeds:

• $12,000 and you are married filing separately;
• $15,000 and you are filing single;
• $19,000 and you are filing head of household; or
• $24,000 and you are married filing jointly or qualifying surviving spouse.