Disability modifications in rentals

That fair housing laws require that landlords permit, at the expense of the person with a disability, reasonable modifications of the rental property if necessary for the tenant’s full enjoyment of the premises? The landlord can require that the tenant restore the property to its original condition when the tenant vacates if the modification will interfere with the next tenant’s use and enjoyment of the rental.  The addition of a wheelchair ramp, adding grab bars in the bathroom or modifying plumbing to accommodate dialysis equipment could all be considered reasonable modifications.