40 CFR Part 63, Table 1
Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
| Monitoring frequency per subpart a | Detection sensitivity level |
|---|---|
| Bi-Monthly | 60 |
| Semi-Quarterly | 85 |
| Monthly | 100 |
a When this alternative work practice is used to identify leaking equipment, the owner or operator must choose one of the monitoring frequencies listed in this table, in lieu of the monitoring frequency specified in the applicable subpart. Bi-monthly means every other month. Semi-quarterly means twice per quarter. Monthly means once per month.
[73 FR 78213, Dec. 22, 2008]