### Question
What is the definition of underground injection?


### Answer
The definition of **underground injection** is as follows in *42 U.S.C. § 300h*:

> the subsurface emplacement of fluids by well injection

#### Citation:
  - *42 U.S.C. § 300h*
  - Heading: **CHAPTER 6A-PUBLIC HEALTH SERVICE > SUBCHAPTER XII-SAFETY OF PUBLIC WATER SYSTEMS > Part C-Protection of Underground Sources of Drinking Water**

