In addition to being funded through a state-funded program designed to establish a minimum educational threshold in every school, Texas public elementary and secondary schools rely on local property taxes for supplemental revenue. Rodriguez, acting on behalf of students whose families reside in poor districts, challenged this funding scheme by arguing that it underprivileged such students because their schools lacked the vast property tax base that other districts utilized. The reliance on assessable property, the school districts claimed, caused severe inter-district disparities in per-pupil expenditures.
https://www.oyez.org/cases/1972/71-1332