In general, concert dress is full black. Additionally, the choir often wears coordinating scarves depending on the theme of the concert. 

If the choir is using scores in the concert, a black binder is required. 

Use a non-crinkly plastic bottle for water.

DO NOT WEAR PERFUME OR OTHER SCENTED PRODUCTS (hair spray, essential oils, etc). Members with allergies deserve to sing in the concert without reacting to ambient smells.

Be mindful of your shoe choices, particularly if you are in front of someone else and wearing high heels. You may wish to bring your concert shoes to the dress rehearsal to help with planning sight lines and visibility.