How would you break down this utility bill?

[Matt Gilroy]

Hello BP,

I have a duplex in Washington State (Spokane City/County) with inherited tenants.  In one lease, it states the landlord will pay up to $100/month for water & garbage specifically.  In the other lease, it states the tenant is responsible for all utilities.

When breaking down the utility bill from the City (water/sewer/garbage), my thought is to pay for 1/2 of the water and 1/2 of the garbage based on the "pay up to $100/month" for one unit.  Also listed on the bill is sewer and water/wastewater capital.  This charge is for capital improvements and upkeep on the water/sewer systems.  I plan to break the charges in half for both tenants and then cover 1/2 of the water and 1/2 of the garbage based on the current lease- not any of the sewer or other related charges for capital improvements.

Thoughts?  Concerns?  Would love to hear your input!