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SEPTIC INSTALLER TEST FOR WASHINGTON STATE
(WOSSA) EXAM QUESTIONS WITH VERIFIED
SOLUTIONS | UPDATED 2026/2027 | GRADED A+ | 100%
CORRECT
ANSI - correct answer -American National Standards Institute
BOD - correct answer -biochemical oxygen demand, typically expressed
in mg/L.
CBOD - correct answer -Carbonaceous Biochemical Oxygen Demand,
expressed in mg/L.
LOSS - correct answer -large on-site sewage system
NSF - correct answer -Nation Sanitation Foundation International
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O&G - correct answer -Oils and Grease, component of sewage typically
originating from food stuffs (animal fats of vegetable oils) expressed in
mg/L.
FC - correct answer -Fecal Coliform, expressed in number of colonies
100/ml.
RS&G - correct answer -Recommended Standards and Guidance
SSAS - correct answer -a subsurface soil absorption system
TAC - correct answer -Technical Advisory Committee established in
WAC 247-272A-0400
TN - correct answer -Total Nitrogen, expressed in mg/L.
USEPA - correct answer -United States Environmental Protection
Agency
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Additive - correct answer -a commercial product added to an onsite
sewage system intended to affect the performance or aesthetics of an on-
site sewage system
Approved - correct answer -Acceptable to the authority having
jurisdiction. Local health officer or the department
BED - correct answer -a soil dispersal component consisting of an
excavation with a width greater than 3 feet
Building Sewer - correct answer -that part of the horizontal piping of a
drainage system which starts from the end of the building drain and
which receives the discharge of the building drain and conveys it to a
public sewer, private sewer, individual sewage disposal system or other
point of disposal. It begins two feet outside the building wall and
conveys sewage from the building drain to the remaining portions of the
on-site sewage system.
Cesspool - correct answer -a covered hole or pit for receiving drainage
or sewage, as from a house allowing liquid to seep into the surronding
rock or soil
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TSS - correct answer -Total Suspended Solids. A measure of the total
suspended solids in a given solution, expressed in mg/L.
Conforming System - correct answer -an on-site sewage system of
component meeting rules of: New construction requirements
Approved and installed within previous requirements
Permitted by WAC-246-272A-0420
Cover Material - correct answer -Soil placed over dispersal component,
made up of mineral material with no greater than 10% organic content.
Cover may contain organic surface material, an organic landscaper to
help reduce and contain soil erosion.
Cuts and Banks - correct answer -a naturally occurring or artificially
formed slope greater than one hundred percent (fortyfive degrees) and
extending vertically at least five from the toe of the slope to top of the
slope.
Department - correct answer -Washington State Department of Health
SEPTIC INSTALLER TEST FOR WASHINGTON STATE
(WOSSA) EXAM QUESTIONS WITH VERIFIED
SOLUTIONS | UPDATED 2026/2027 | GRADED A+ | 100%
CORRECT
ANSI - correct answer -American National Standards Institute
BOD - correct answer -biochemical oxygen demand, typically expressed
in mg/L.
CBOD - correct answer -Carbonaceous Biochemical Oxygen Demand,
expressed in mg/L.
LOSS - correct answer -large on-site sewage system
NSF - correct answer -Nation Sanitation Foundation International
, Page | 2
O&G - correct answer -Oils and Grease, component of sewage typically
originating from food stuffs (animal fats of vegetable oils) expressed in
mg/L.
FC - correct answer -Fecal Coliform, expressed in number of colonies
100/ml.
RS&G - correct answer -Recommended Standards and Guidance
SSAS - correct answer -a subsurface soil absorption system
TAC - correct answer -Technical Advisory Committee established in
WAC 247-272A-0400
TN - correct answer -Total Nitrogen, expressed in mg/L.
USEPA - correct answer -United States Environmental Protection
Agency
, Page | 3
Additive - correct answer -a commercial product added to an onsite
sewage system intended to affect the performance or aesthetics of an on-
site sewage system
Approved - correct answer -Acceptable to the authority having
jurisdiction. Local health officer or the department
BED - correct answer -a soil dispersal component consisting of an
excavation with a width greater than 3 feet
Building Sewer - correct answer -that part of the horizontal piping of a
drainage system which starts from the end of the building drain and
which receives the discharge of the building drain and conveys it to a
public sewer, private sewer, individual sewage disposal system or other
point of disposal. It begins two feet outside the building wall and
conveys sewage from the building drain to the remaining portions of the
on-site sewage system.
Cesspool - correct answer -a covered hole or pit for receiving drainage
or sewage, as from a house allowing liquid to seep into the surronding
rock or soil
, Page | 4
TSS - correct answer -Total Suspended Solids. A measure of the total
suspended solids in a given solution, expressed in mg/L.
Conforming System - correct answer -an on-site sewage system of
component meeting rules of: New construction requirements
Approved and installed within previous requirements
Permitted by WAC-246-272A-0420
Cover Material - correct answer -Soil placed over dispersal component,
made up of mineral material with no greater than 10% organic content.
Cover may contain organic surface material, an organic landscaper to
help reduce and contain soil erosion.
Cuts and Banks - correct answer -a naturally occurring or artificially
formed slope greater than one hundred percent (fortyfive degrees) and
extending vertically at least five from the toe of the slope to top of the
slope.
Department - correct answer -Washington State Department of Health
