MADISON, Wis. (AP) — Republican lawmakers are looking to streamline Wisconsin’s water pollution credits system.

Currently fixed sources of pollution such as wastewater treatment plants can exceed pollutant levels in their state permits by purchasing credits from other sources such as farms that have taken steps to reduce their pollution. Only a handful of such transactions have taken place in the state, however.

A group of Republican legislators introduced a bill Tuesday that would create a clearinghouse between fixed-source polluters and credit generators. The clearinghouse would enter into contracts with credit generators and assume liability for the viability of their credits.

The bill’s supporters say the new system could provide another source of revenue for farmers and improve water quality.

Gov. Tony Evers has declared 2019 the year of clean drinking water.