How many bytes are used to store null values in data lake?

[Geeta1]

Generally they require 1 byte

[DB_developer]

Can you please provide any supporting documentation ?

[-werners-]

there is no single answer to this.

If you look at parquet, which is a very common format on data lakes:

https://parquet.apache.org/docs/file-format/nulls/

and on SO