(iii) The landlord provides the tenants with a copy of the water bill for the period in which the penalty was charged. Only penalties billed for a service period which begins after the effective date of the ordinance [April 20, 1991] may be passed through to tenants. Where penalties result from an allocation which does not reflect documented changes in occupancy which occurred after March 1, 1991, a landlord must, if requested in writing by a tenant, make a good-faith effort to appeal the allotment. Increases based upon penalties shall be prorated on a per-room basis provided that the tenancy existed during the time the penalty charges accrued. Such charges shall not become part of a tenant's base rent. Where a penalty in any given billing period reflects a 25 percent or more increase in consumption over the prior billing period, and where that increase does not appear to result from increased occupancy or any other known use, a landlord may not impose any increase based upon such penalty unless inspection by a licensed plumber or Water Department inspector fails to reveal a plumbing or other leak. If the inspection does reveal a leak, no increase based upon penalties may be imposed at any time for the period of the unrepaired leak.