It shall be unlawful for any person required to pay a public sewer system user fee under this chapter to assess against any tenant an amount for such fee in excess of the actual public sewer system user fee which can be attributed to such tenant's unit. If the person is required to pay a public sewer system user fee with respect to more than one unit, the amount which can be attributed to each unit must be prorated equally between the units. Penalties assessed against the landlord/owner shall not be passed on to the tenants.