Renting out an ADU, what do you do about utilities?

Hello,

I am looking to purchase a property to rent out and construct an Additional Dwelling Unit to rent out as well, as a long term rental (more than 6 months). The city code doesn't allow me to hook up water, electric or gas separately for the ADU.

What would you guys recommend in this situation? Are there any self sufficient systems or ideas that I could look into? My goal is to separate out the utility costs, the only way I can think to do this is by dividing up the utility costs by square footage. Thoughts?

Thanks!