Can a non-owner be a member of a committee in a condominium?

Read your governing documents to determine the composition of committees.

Usually, at least one board member is required to be a member.

Read the committee's charter, to determine its task, resources and time limits. Key here is whether or not the committee has been given the power of the board to act on behalf of the board.

If no power to act exists, and the board is simply advisory, it is reasonable that the board be composed of knowledgeable members. If one is a non-owner, and has been vetted by the board, and can contribute, that person could be valuable to the committee's work. (In the vetting process, the person must not carry in any conflict of interest, such as being a vendor in the genre where the committee operates, or be able in any way to benefit from association funds.)

Transparency is key, so that should a query arise, the committee can defend the inclusion of a non-owner as a contributing member.