; (ii) at least once every 6 months during the period beginning at the commencement of underground injection described in clause (i) and ending at the cessation of such hydraulic fracturing operations; and (iii) at least once every 12 months during the 5-year period following the end of the period described in clause (ii); (B) with respect to a site where, as of the date of enactment of this section, there is no active underground injection, but underground injection has previously occurred at the site— (i) prior to renewing underground injection at the site; (ii) at least once every 6 months during the period beginning at such renewal of underground injection and ending at the cessation of such hydraulic fracturing operations; and (iii) at least once every 12 months during the 5-year period following the end of the period described in clause (ii); and (C) with respect to a site where, as of the date of enactment of this section, such hydraulic fracturing operations are occurring— (i) at least once every 6 months during the period beginning on the date of enactment of this section ending at the cessation of such hydraulic fracturing operations; and (ii) at least once every 12 months during the 5-year period following the end of the period described in clause (i); and (2) to submit reports to the Administrator on the results of testing under subparagraph (A), (B), or (C) of paragraph (1) within 2 weeks of such testing. (b) Exception The testing and reporting requirements of subsection (a) do not apply with respect to hydraulic fracturing operations if there is no accessible underground source of drinking water within a radius of one mile of the site where the operations occur. (c) Sampling locations Testing required pursuant to subsection (a) shall occur— (1) at all accessible underground sources of drinking water within a radius of one-half mile of the site where the hydraulic fracturing operations occur