NJDEP Treatment Works Approval (TWA)
Questions With Complete Solutions
Permitted sewers are designed with capacity________ At least twice the estimated
average design flow when flowing half full.
Permitted sewers are designed with slope_________ 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? 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________ Changes in pipe size, grade, alignment,
and sewer intersections
Drop manholes are not required until invert is elevated at least__________above manhole
bottom 24 inches
Maximum manhole separation is equal to________ 400 ft
Questions With Complete Solutions
Permitted sewers are designed with capacity________ At least twice the estimated
average design flow when flowing half full.
Permitted sewers are designed with slope_________ 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? 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________ Changes in pipe size, grade, alignment,
and sewer intersections
Drop manholes are not required until invert is elevated at least__________above manhole
bottom 24 inches
Maximum manhole separation is equal to________ 400 ft
