Retaliatory conduct prohibited. ...
(d) ... the landlord may increase the rent if the landlord(1) has become liable for a substantial increase in property taxes, or a substantial increase in other maintenance or operating costs not associated with compliance with the complaint or request, not less than four months before the demand for an increase in rent; and the increase in rent bears a reasonable relationship to the net increase in taxes or costs;...
(2) has completed a capital improvement of the dwelling unit or the property of which it is a part and the increase in rent does not exceed the amount that may be claimed for federal income tax purposes as a straight-line depreciation of the improvement, prorated among the dwelling units benefited by the improvement;
(3) can establish by competent evidence that the rent now demanded of the tenant does not exceed the rent charged other tenants of similar dwelling units in the building or, in the case of a single-family residence or if there is no similar dwelling unit in the building, does not exceed the fair rental value of the dwelling unit.
Title 34, Sec. 34.03.310
30 Day Notice to Tenant of Increase in Rent for...
