You may remain on reduced monitoring after the dates identified in Sec. 141.620(c) for compliance with this subpart only if you qualify for a 40/30 certification under Sec. 141.603 or have received a very small system waiver under Sec. 141.604, plus you meet the reduced monitoring criteria in Sec. 141.623(a), and you do not change or add monitoring locations from those used for compliance monitoring under subpart L of this part. If your monitoring locations under this subpart differ from your monitoring locations under subpart L of this part, you may not remain on reduced monitoring after the dates identified in Sec. 141.620(c) for compliance with this subpart.