Single family house with ADU and above ground spa

[Rajan Ch]

I just bought a property in Los Angeles county with 2 units. I am trying to see the best way to rent it out. The original front house is 1500 sq ft and a detached garage is turned into a 1000 sq ft ADU. There is a long driveway and alley so both units have easy access. The challenging issue is there is an above ground spa installed in between the two units and a common area with outdoor furniture by the spa. The utilities for the spa such as electricity (water pump and to heat) is tied to the ADU interestingly. I pay for water so that is not an issue for anybody. How should the lease be structured as far as both tenants enjoying the common area, but most importantly, the use of the spa, since only the back tenant is having to pay for its utilities and myself paying for the water. I feel like not giving the front unit access to it seems weird since it's part of the common area but the back unit is having to pay its electricity ? Any thoughts ? thank you.