to my knowledge, OT not require water baptism.
Baptism may not have been a requirement in the OT, but there was symbolism for it in the OT and the NT spoke of how the OT saints were baptized.
Exodus 19:10-11
And the LORD said unto Moses, Go unto the people, and
sanctify them to day and to morrow, and let them
wash their clothes, And be ready against the third day: for the third day the LORD will come down in the sight of all the people upon mount Sinai.
Exodus 29:4
And Aaron and his sons thou shalt bring unto the door of the tabernacle of the congregation, and shalt
wash them with water.
Hebrews 9:18-20
Whereupon neither the first testament was dedicated without blood. For when Moses had spoken every precept to all the people according to the law, he took the
blood of calves and of goats,
with water, and scarlet wool, and hyssop, and
sprinkled both the book, and all the people, Saying, This is the blood of the testament which God hath enjoined unto you.
1 Corinthians 10:1-2
For I do not want you to be unaware, brothers, that our fathers were all under the cloud, and all passed through the sea, and all were
baptized into Moses in the cloud and in the sea