Ohio Rev. Code § 727.03
The legislative authority of a municipal corporation shall limit all special assessments levied under sections 727.01 to 727.49, inclusive, of the Revised Code, to the special benefits conferred upon the property assessed. In no case shall there be levied, under sections 727.01 to 727.49, inclusive, of the Revised Code, upon a lot or parcel of land in the municipal corporation, any assessment for any purpose which, together with all assessments made for all other purposes within a period of five years preceding the passage of the assessing ordinance under section 727.25 of the Revised Code, would be in excess of thirty-three and one-third per cent of the actual value of such lot or parcel including improvements thereon, as enhanced by the improvement for which the assessment is levied, such value to be determined as of the date of the assessing ordinance passed under section 727.25 of the Revised Code, except as provided by section 727.06 of the Revised Code. Assessments levied for the construction of main sewers shall not exceed the sum that, in the opinion of the legislative authority, would be required to construct an ordinary street sewer or drain of sufficient capacity to drain or sewer the lots or lands to be assessed for such improvement, nor shall any lots or lands be assessed that are provided with adequate drainage.
R.C. §727.03