40 CFR § 146.23 - Operating, monitoring, and reporting requirements.
(a) Operating requirements. Operating requirements shall, at a minimum, specify that:
(1) Injection pressure at the wellhead shall not exceed a maximum which shall be calculated so as to assure that the pressure during injection does not initiate new fractures or propagate existing fractures in the confining zone adjacent to the USDWs. In no case shall injection pressure cause the movement of injection or formation fluids into an underground source of drinking water
(b) Monitoring requirements. Monitoring requirements shall, at a minimum, include:
(1) Monitoring of the nature of injected fluids at time intervals sufficiently frequent to yield data representative of their characteristics;
(ii) Monthly for enhanced recovery operations;
(iii) Daily during the injection of liquid hydrocarbons and injection for withdrawal of stored hydrocarbons; and
(iv) Daily during the injection phase of cyclic steam operations
(5) Hydrocarbon storage and enhanced recovery may be monitored on a field or project basis rather than on an individual well basis by manifold monitoring. Manifold monitoring may be used in cases of facilities consisting of more than one injection well, operating with a common manifold. Separate monitoring systems for each well are not required provided the owner/operator demonstrates that manifold monitoring is comparable to individual well monitoring.
(c) Reporting requirements.
(1) Reporting requirements shall at a minimum include an annual report to the Director summarizing the results of monitoring required under paragraph (b) of this section. Such summary shall include monthly records of injected fluids, and any major changes in characteristics or sources of injected fluid. Previously submitted information may be included by reference.