40 CFR 146.33 - Operating, monitoring, and reporting requirements.
(a) Operating requirements. Operating requirements prescribed shall, at a minimum, specify that:
(1) Except during well stimulation injection pressure at the wellhead shall be calculated so as to assure that the pressure in the injection zone during injection does not initiate new fractures or propagate existing fractures in the injection zone. In no case, shall injection pressure initiate fractures in the confining zone or cause the migration of injection or formation fluids into an underground source of drinking water.
(2) Injection between the outermost casing protecting underground sources of drinking water and the well bore is prohibited.
(b) Monitoring requirements. Monitoring requirements shall, at a minimum, specify:
(1) Monitoring of the nature of injected fluids with sufficient frequency to yield representative data on its characteristics. Whenever the injection fluid is modified to the extent that the analysis required by § 146.34(a)(7)(iii) is incorrect or incomplete, a new analysis as required by § 146.34(a)(7)(iii) shall be provided to the Director.
(2) Monitoring of injection pressure and either flow rate or volume semi-monthly, or metering and daily recording of injected and produced fluid volumes as appropriate.
(3) Demonstration of mechanical integrity pursuant to § 146.08 at least once every five years during the life of the well for salt solution mining.
(4) Monitoring of the fluid level in the injection zone semi-monthly, where appropriate and monitoring of the parameters chosen to measure water quality in the monitoring wells required by § 146.32(e), semi-monthly.
(5) Quarterly monitoring of wells required by § 146.32(g).
(6) All Class III wells may be monitored on a field or project basis rather than 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. Reporting requirements shall, at a minimum, include:
(1) Quarterly reporting to the Director on required monitoring;
(2) Results of mechanical integrity and any other periodic test required by the Director reported with the first regular quarterly report after the completion of the test; and
(3) Monitoring may be reported on a project or field basis rather than individual well basis where manifold monitoring is used.