Washing machines

Hi I am in the middle of renovating a building that contains self contained flats. There are 2 on the top floor (let)
3 on the middle floor
and 4 on the ground floor.

There is a communal washing machine and tumble dryer that the two top flats use - seems to be on 24/7 I am footing bill for al electricity and gas at the moment.

Part of the renovation will be to meter separately each flat with Electric and get rid of gas. I will reduce their rent to take care of this.

I don't really want to have a communal washing room although I could do this. I don't really want to pay for their washing.

My builders suggested 3 things

1. Get rid of any washing machines
2. Have a washing room with 3 or 4 washing machines - but how would these get charged, do not want to charge extra rent or have metered machines
3. Put a small machine in each room and have no tumble dryer. (There is no where to hang washing outside, it will need to be put on clothes horse in flats.

So do I need to provide machines, what are the options and does anyone have any other ideas?

ta

Mark