---
kind: "section"
citation: "40 C.F.R. § 63.1964"
title: "40"
number: "63.1964"
heading: "How is compliance determined?"
url: "https://uscodex.org/cfr/40/63.1964"
---

# §63.1964. How is compliance determined?


Compliance is determined using performance testing, collection system monitoring, continuous parameter monitoring, and other credible evidence. In addition, continuous parameter monitoring data collected under § [63.1961(b)(1)](/cfr/40/63.1961.md?p=b-1), [(c)(1)](/cfr/40/63.1961.md?p=c-1), and [(d)](/cfr/40/63.1961.md?p=c-d) are used to demonstrate compliance with the operating standards for control systems. If a deviation occurs, you have failed to meet the control device operating standards described in this subpart and have deviated from the requirements of this subpart.

- (a) Before September 28, 2021, you must develop a written SSM plan according to the provisions in [§ 63.6(e)(3)](/cfr/40/63.6.md?p=e-3) of subpart A. A copy of the SSM plan must be maintained on site. Failure to write or maintain a copy of the SSM plan is a deviation from the requirements of this subpart.
- (b) After September 27, 2021, the SSM provisions of [§ 63.6(e)](/cfr/40/63.6.md?p=e) of [subpart A](/cfr/40/subpartA.md) no longer apply to this subpart and the SSM plan developed under [paragraph (a)](#a) of this section no longer applies. Compliance with the emissions standards and the operating standards of [§ 63.1958](/cfr/40/63.1958.md) of this subpart is required at all times.

## Notes

### Source

Source: 85 FR 17261, Mar. 26, 2020, unless otherwise noted.

### Authority

Authority: 42 U.S.C. 7401 et seq.

### Source

Source: 57 FR 61992, Dec. 29, 1992, unless otherwise noted.