### Question
How does SUBCHAPTER N—EFFLUENT GUIDELINES AND STANDARDS define blowdown?


### Answer
Under *40 CFR § 401.11*, **blowdown** is defined as:

> 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: **PART 401—GENERAL PROVISIONS > SUBCHAPTER N—EFFLUENT GUIDELINES AND STANDARDS > SUBCHAPTER N—EFFLUENT GUIDELINES AND STANDARDS**

