lead and copper rule
...that the EPA's lead and copper rule restricts allowable lead levels in drinking water to 15 parts per billion?
...that the <a href="./United_States_Environmental_Protection_Agency" id="mwETI" rel="mw:WikiLink" title="United States Environmental Protection Agency">EPA</a>'s <b id="mwETM"><a class="mw-redirect" href="./Lead_and_copper_rule" id="mwETQ" rel="mw:WikiLink" title="Lead and copper rule">lead and copper rule</a></b> restricts allowable <a href="./Lead" id="mwETU" rel="mw:WikiLink" title="Lead">lead</a> levels in <a href="./Drinking_water" id="mwETY" rel="mw:WikiLink" title="Drinking water">drinking water</a> to 15 <a class="mw-redirect" href="./Parts_per_billion" id="mwETc" rel="mw:WikiLink" title="Parts per billion">parts per billion</a>?