Pursuant to the Family Law Act of British Columbia a child is defined in section 146 as follows:
“child” includes a person who is 19 years of age or older and unable, because of illness, disability or another reason, to obtain the necessaries of life or withdraw from the charge of his or her parents or guardians
Child maintenance is payable for any child who is under the age of majority whether or not the child has a relationship with the parent. Only once this child is over the age of majority does the child’s relationship with the parent become a relevant factor.
If the child is under 19 and is either married or living in a common-law relationship for more than one year or the child has voluntarily withdrawn from his or her parents’ care then child maintenance is not payable.
Section 147(1) of the Family Law Act states:
147 (1) Each parent and guardian of a child has a duty to provide support for the child, unless the child
(a) is a spouse, or
(b) is under 19 years of age and has voluntarily withdrawn from his or her parents’ or guardians’ charge, except if the child withdrew because of family violence or because the child’s circumstances were, considered objectively, intolerable.
The Divorce Act at section 2(1) and (2) states:
(1) In this Act, “child of the marriage” means a child of two spouses or former spouses who, at the material time,
(b) is the age of majority or over and under their charge but unable, by reason of illness, disability or other cause, to withdraw from their charge or to obtain the necessaries of life;
(a) is under the age of majority and who has not withdrawn from their charge, or
(2) For the purposes of the definition “child of the marriage” in subsection (1), a child of two spouses or former spouses include
(a) any child for whom they both stand in the place of parents; and
(b) any child of whom one is the parent and for whom the other stands in the place of a parent.
In summary child maintenance in B.C. is payable for any child who is under 19 unless they are married or have left home. If they are over 19 child maintenance is payable for so long as the child remains dependent on their parents or is in school and unable to support themselves.