What type of disability is it? VA, SSDI, SSI, or something else?
VA disability is never taxable. Below is some information about the other two:
Social Security Disability Insurance (SSDI). Social Security Disability Insurance benefits are paid to individuals who have long-term disabilities. Coverage is based on earnings tests. SSDI benefits are potentially taxable in the same manner as retirement benefits, depending on the recipient’s other income.
Supplemental Security Income (SSI). If an individual is disabled, blind, or age 65 or over, has limited income, and does not have enough work history to be covered under SSDI, he or she may qualify for Supplemental Security Income. Payments under SSI are not taxable and are not included with other Social Security benefits when determining the taxable portion.
More information can be found on the Social Security website here.