Can I claim an unrelated child as a dependent

[cebax]

This child is 17, she is the daughter of my wife's, uncle's ex-girlfriend.  She has been part of our family for nearly 10 years.  She initially left home March/April 2019 and began to live with my sister-in-law.   This August 2019 she moved in with my wife and I due to Child Protective Services asking to interview my 11yr old niece and 4yr old nephew during routine visits which nobody was comfortable with.  We are providing full support for her as if she was our own child. 

I would like to add her to our insurance, we meet the requirements according to our benefits administrator, however, the form to submit the change asks if I am able to claim the child as a exemption for federal tax purposes.  I'm confident her mother is going to claim her this year but assuming she didn't am I able to claim her?

[DoninGA]

Since the child is not related to you they must live in your home for the entire year and meet the other requirements under the Qualifying Relative rules before you would be able to claim her as your dependent.

To be a Qualifying Relative -

1. The person cannot be your qualifying child or the qualifying child of any other taxpayer. A child is not the qualifying child of any other taxpayer if the child's parent (or any other person for whom the child is defined as a qualifying child) is not required to file an income tax return or files an income tax return only to get a refund on income tax withheld.
2. The person either (a) must be related to you or (b) must live with you all year as a member of your household.
3. The person's gross income for the year must be less than $4,150 (social security does not count) in 2018
4. You must provide more than half of the person's total support for the year.
5. The person must be a U.S. citizen or a U.S., Canada, or Mexico resident for some part of the year.
6. The person must not file a joint return with their spouse.

[cebax]

Thank you for the quick reply.  The gross income level is extremely low, Is there any stipulation that this does not apply to an 18-24 yr old child that is a full time student?  Otherwise the only legal way to claim her is to have her quit her part-time job and claim her next year.

[DoninGA]

Since she is not your child, she cannot be a Qualifying Child for tax purposes where if she were a full time student under the age of 24 her gross income would not be a factor when claiming her as a dependent.

As it is she is not related to you and her age is not a factor but the time lived in your home and her gross income is a factor.  For tax year 2019 the gross income must be less than $4,200 plus she must have lived in your home for the whole year, 01/01/2019 thru 12/31/2019.