Ohio Rev. Code Ann. § 3718.012

A sewage treatment system that was in operation prior to the effective date of this section shall not be required to be replaced with a new sewage treatment system under this chapter or rules adopted under it and shall be deemed approved if the system does not cause a public health nuisance or, if the system is causing a public health nuisance as provided in section 3718.011 of the Revised Code, repairs are made to the system that eliminate the public health nuisance as determined by the applicable board of health.