New Bedford Mayor Jon Mitchell was on Beacon Hill Tuesday pushing for an overhaul of the state funding mechanism for charter schools.

Testifying before the Joint Committee on Education, Mitchell said the city's efforts to improve its schools has been hamstrung by the state charter school funding mechanism. He said the net fiscal impact of charter schools in New Bedford since taking office in 2012 has doubled from $7 million to $14 million.

Mitchell urged the Committee to endorse House Bill 418, filed by Rep. Antonio Cabral of New Bedford. He said the bill would cap assessments on cities and towns used to finance charter school tuition payments.

The bill would also limit the local contributions to charter schools, and provide for state payment of the balance, subject to appropriation.

Mitchell added House 418, if passed, would be a "game-changer" for the City of New Bedford, lowering its charter school obligations by $6 million in fiscal 2019, according to estimates from the Department of Elementary and Secondary Education.

The bill would also amend the state's charter school finance law to create a local share and a state share of charter school tuition payments.