Adding utilities on month to month

[Ami Son]

I have purchased a 4plex in San Diego a couple years ago. It is currently barely cash flowing, but the rents with the current tenants that came with the property are so below the market value. I have been raising the rent every year with the maximum amount allowed, but it is no where near reaching an appropriate amount.

The tenants have lived there for years and now on a month to month. In the original lease, the utilities of water and trash are included and tenants pay for electricity and gas. I am in the process of installing solar panels and my end goal is to take over all their “electrical bills” and charging a separate utilities fee.

My question is..

Is that allowed? Since they are on a month to month, could I make changes to the way that the utilities are being paid?

And since I am increasing the rent to the maximum allowed amount, would charging a new separate amount of utilities interfere??

Thank you so much in advance!!