40 CFR § 149.2 - Definitions.
---
identifier: "/us/cfr/t40/s149.2"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 149.2 - Definitions."
title_number: 40
title_name: "Protection of Environment"
section_number: "149.2"
section_name: "Definitions."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "D"
subchapter_name: "WATER PROGRAMS"
part_number: "149"
part_name: "SOLE SOURCE AQUIFERS"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "Sec. 1424(e), Safe Drinking Water Act (42 U.S.C. 300h-3(e); sec. 1427 of the Safe Drinking Water Act, (42 U.S.C. 300h-6)."
cfr_part: "149"
---
# 149.2 Definitions.
(a) *Aquifer* means a geological formation, group of formations, or part of a formation that is capable of yielding a significant amount of water to a well or spring.
(b) *Recharge* means a process, natural or artificial, by which water is added to the saturated zone of an aquifer.
(c) *Recharge Area* means an area in which water reaches the zone of saturation (ground water) by surface infiltration; in addition, a *major recharge area* is an area where a major part of the recharge to an aquifer occurs.
(d) *Sole or Principal Source Aquifer* (SSA) means an aquifer which is designated as an SSA under section 1424(e) of the SDWA.
[54 FR 6843, Feb. 14, 1989]