Dimension Properties utilizes a “Ratio Utility Billing System” (“RUBS”) to divide the utility costs of a building between individual units. The portion each individual apartment is charged is determined by the number of bedrooms and bathrooms each apartment has, with each bedroom and each bathroom constituting 1 unit for calculating the ratio.

To illustrate this, lets use a fictional apartment complex called Blackacre Apartments. The complex has 5 apartments: Apartment A has 1 bedroom and 1 bathroom, Apartment B has 2 bedrooms and 1 bathroom, Apartment C and D each have 2 bedrooms and 2 bathrooms, and Apartment E has 3 bedrooms and 2 bathrooms. The apartments convert to the units below:

- Apartment A is 2 units (1 bedroom + 1 bath)
- Apartment B is 3 units (2 bedrooms + 1 bath)
- Apartment C is 4 units (2 bedrooms + 2 baths)
- Apartment D is 4 units (2 bedrooms + 2 baths)
- Apartment E is 5 units (3 bedrooms + 2 baths)
- Blackacre Apartments’ total units is 18

The utility company sends Dimension Properties a bill for the entire complex of $180.00 for the month. Under RUBS, Dimension will divide the utility bill by the number of units each apartment has compared to the whole. For example, Apartment A has 2 units, so their portion of the utility payment is 2/18ths of the main bill or $20. As such, Dimension divides the costs of the bill as follows:

- Apartment A is billed $20
- Apartment B is billed $30
- Apartment C is billed $40
- Apartment D is billed $40
- Apartment E is billed $50

This billing system is consistent with the provisions of the Residential Landlord-Tenant Act (RCW 59.18).