### Question
How does the law define significant nexus?


### Answer
Under *40 CFR § 300.5*, **significant nexus** is defined as:

> that a water, including wetlands, either alone or in combination with other similarly situated waters in the region, significantly affects the chemical, physical, or biological integrity of a water identified in paragraphs (1)(i) through (iii) of this definition. 

#### Citation:
  - *40 CFR § 300.5*
  - Heading: **PART 300—NATIONAL OIL AND HAZARDOUS SUBSTANCES POLLUTION CONTINGENCY PLAN > Subpart A—Introduction**

