### Question
How is the "blowdown" defined?


### Answer
The term **blowdown** is defined in *40 CFR § 401.11* as follows -

> the minimum discharge of recirculating water for the purpose of discharging materials contained in the water, the further buildup of which would cause concentration in amounts exceeding limits established by best engineering practice.

#### Citation:
  - *40 CFR § 401.11*
  - Heading: **Title 40—Protection of Environment > PART 401—GENERAL PROVISIONS > CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)**

