The school tax exemption assessed the home that you and your mother purchased together was placed when the property was acquired based upon its purchase price. This exemption placed upon the home was done by the county tax assessor for the state you live it.The school tax exemption has no bearing upon any refinance of the home jointly owned by you and your mother. Most likely it was placed due to the age of your mother and the fact that she is one of its legal owners.It is up to the the county tax assessor to re-assess the property tax exemption on the property if it is incorrect. You have no obligation to notify the county if in fact the school tax exemption is improperly in place. If you sell the property without the assessment for school in place, so be it.Most likely if title to the property is transferred to a third party, the county tax assessor will re-assess local taxes for the parcel.Potentially, the school tax exemption on the property is proper.