40 CFR § 124.20 - Computation of time.

---
identifier: "/us/cfr/t40/s124.20"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 124.20 - Computation of time."
title_number: 40
title_name: "Protection of Environment"
section_number: "124.20"
section_name: "Computation of time."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "D"
subchapter_name: "WATER PROGRAMS"
part_number: "124"
part_name: "PROCEDURES FOR DECISIONMAKING"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "Resource Conservation and Recovery Act, 42 U.S.C. 6901  Safe Drinking Water Act, 42 U.S.C. 300f  Clean Water Act, 33 U.S.C. 1251  Clean Air Act, 42 U.S.C. 7401"
regulatory_source: "48 FR 14264, Apr. 1, 1983, unless otherwise noted."
cfr_part: "124"
---


# 124.20 Computation of time.

(a) Any time period scheduled to begin on the occurrence of an act or event shall begin on the day after the act or event.

(b) Any time period scheduled to begin before the occurrence of an act or event shall be computed so that the period ends on the day before the act or event.

(c) If the final day of any time period falls on a weekend or legal holiday, the time period shall be extended to the next working day.

(d) When a party or interested person may or must act within a prescribed period after being served and service is made by U.S. mail, EPA's internal mail, or reliable commercial delivery service, 3 days shall be added to the prescribed time. The prescribed period for acting after being served is not expanded by 3 days when service is made by personal delivery, facsimile, or email.

[48 FR 14264, Apr. 1, 1983, as amended at 82 FR 2237, Jan. 9, 2017]