Rules proposed to limit lawns of new homes to no more than 25 percent of the 35 percent of the required landscaping area for the front yard will not apply to existing homes. Should the Manteca Planning Commission Tuesday recommend approval of the new rule to reduce future water consumption of new homes and it is also adopted by the City Council, staff said existing homes will become legal non-conforming uses.That means if existing home owners opt to let their front yard lawns die for the duration of the drought they will not have to comply with new rules capping lawn sizes when they go to restore their yards. It is much like other rules regarding home setbacks and such that have been adopted over the years and have changed the face of Manteca.