NJDEP Treatment Works Approval (TWA) – Questions &
Complete Solutions
Either of these two things trigger requirement of a TWA permit Right Ans -
Building or modifying service which will either:
1. Provide service to more than two buildings OR
2. Increase anticipated flow by at least 8,000 GPD
One or both of these requirements must be met to qualify for an expedited
TWA permit review Right Ans - 1. The project requires the construction of
a sanitary sewer lateral only and does not involve the construction of a sewer
extension along an easement through more than two properties, a roadway or
public rightof-way.
2. The project requires the construction of a sanitary sewer extension not
exceeding 400 feet.
Outline the Typical TWA review process Right Ans - 1. Submit for sign-off
from local municipality (Conveyance system owner, governing body)
2. Submit for sign-off from wastewater treatment facility owner
3. Request drop off appointment if requesting expedited review
4. Submit to NJDEP
Permitted sewers are designed with capacity________ Right Ans - At least
twice the estimated average design flow when flowing half full.
Permitted sewers are designed with slope_________ Right Ans - A hydraulic
slope providing an average velocity of at least 2 fps when flowing full or half
full
Permitted sewers are designed at what depth? Right Ans - All laterals are
proposed to be constructed at least 3 ft below the proposed grade. (meaning
top of pipe at least 3ft deep). This is the design standard on all projects
Manholes / Cleanouts are required at________ Right Ans - Changes in pipe
size, grade, alignment, and sewer intersections
Drop manholes are not required until invert is elevated at least__________above
manhole bottom Right Ans - 24 inches
Complete Solutions
Either of these two things trigger requirement of a TWA permit Right Ans -
Building or modifying service which will either:
1. Provide service to more than two buildings OR
2. Increase anticipated flow by at least 8,000 GPD
One or both of these requirements must be met to qualify for an expedited
TWA permit review Right Ans - 1. The project requires the construction of
a sanitary sewer lateral only and does not involve the construction of a sewer
extension along an easement through more than two properties, a roadway or
public rightof-way.
2. The project requires the construction of a sanitary sewer extension not
exceeding 400 feet.
Outline the Typical TWA review process Right Ans - 1. Submit for sign-off
from local municipality (Conveyance system owner, governing body)
2. Submit for sign-off from wastewater treatment facility owner
3. Request drop off appointment if requesting expedited review
4. Submit to NJDEP
Permitted sewers are designed with capacity________ Right Ans - At least
twice the estimated average design flow when flowing half full.
Permitted sewers are designed with slope_________ Right Ans - A hydraulic
slope providing an average velocity of at least 2 fps when flowing full or half
full
Permitted sewers are designed at what depth? Right Ans - All laterals are
proposed to be constructed at least 3 ft below the proposed grade. (meaning
top of pipe at least 3ft deep). This is the design standard on all projects
Manholes / Cleanouts are required at________ Right Ans - Changes in pipe
size, grade, alignment, and sewer intersections
Drop manholes are not required until invert is elevated at least__________above
manhole bottom Right Ans - 24 inches
