From the Roman Missal, for Holy Thursday – Mass of the Lord’s Supper:
“Washing of Feet
Depending on pastoral circumstances, the washing of feet follows the homily.
The men who have been chosen are led by the ministers to chairs prepared in a suitable place. Then the priest (removing his chasuble if necessary) goes to each man. With the help of the ministers, he pours water over each one’s feet and dries them.”
(From Roman Missal, Catholic Book Publishing Co., New York, 1985, page 136).
The Latin text in the 2002 Roman Missal is:
“Lotio pedum
10. Completa homilia proceditur, ubi ratio pastoralis id suadeat, ad lotionem pedum.
11. Viri selecti deducuntur a ministris ad sedilia loco apto parata. Tunc sacerdos (deposita, si necesse sit, casula) accedit ad singulos, eisque fundit aquam super pedes et abstergit, adiuvantibus ministris.”
(Missale Romanum, Libreria Editrice Vaticana, 2002, ISBN: 8820972719, page 300).
In the Ceremonial of Bishops it has:
“301 … Depending on pastoral circumstances, the washing of feet follows the homily.
The men who have been chosen are led by the ministers to chairs provided in a suitable place. Then the bishop (laying aside the mitre and chasuble but not the dalmatic, if he is wearing one) puts on a linen apron (gremial), as circumstances suggest. He then goes to each man and, with the help of the deacons, pours water on each one’s feet and dries them.”
(Ceremonial of Bishops, Liturgical Press, 1989, ISBN 0-8146-1818-9, page 104).