Editing Methyl tert-butyl ether (section)

===Drinking water regulations===
EPA first listed MTBE in 1998 as a candidate for development of a national [[Maximum Contaminant Level]] (MCL) standard in drinking water.<ref>EPA (1998-03-02). "Announcement of the Drinking Water Contaminant Candidate List." ''Federal Register'', {{usfr|63|10274}}</ref> The agency listed MTBE on its [[Safe Drinking Water Act#Unregulated contaminants|Contaminant Candidate List]] in 2022 but has not announced whether it will develop an MCL.<ref>EPA (2022-11-14). "Drinking Water Contaminant Candidate List 5―Final." ''Federal Register,'' {{USFR|87|68060}}</ref>
EPA uses toxicity data in developing MCLs for [[public water system]]s.<ref>{{cite web |url=https://www.epa.gov/dwregdev/how-epa-regulates-drinking-water-contaminants |title=How EPA Regulates Drinking Water Contaminants |author=<!--Not stated--> |date=2017-05-03 |publisher=EPA}}</ref>

California established a state-level MCL for MTBE, 13 micrograms per liter, in 2000.<ref>{{cite web |url=https://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/MTBE.html |title=MTBE: Regulations and Drinking Water Monitoring Results |author=<!--Not stated--> |date=2014-08-04 |publisher=California State Water Resources Control Board |location=Sacramento, CA}}</ref>