raising rent on only one side of a duplex

[Elizabeth Blazina]

Hi ,

Is it legal to raise the rent on only one side of a rental.  I may be answering my own question here, but last year we fixed up one side when an old tenant left and a new one came and then raised that units rent.  I am not wanting to raise that one this year but would like raise the other side due to inflationary components.. Is this legal?

Thanks in advance,