Page | 1
2.4 - CONTRACTOR – PRIVATE SEWERAGE
SYSTEMS QUESTIONS WITH DETAILED
VERIFIED ANSWERS
(E) What is the primary purpose of a septic tank in a sewage treatment
system? Ans: To separate solid waste from liquid effluent through
sedimentation and flotation, allowing clarified effluent to flow to the
leaching field.
(M) According to Quebec regulations, what is the minimum required
distance between a septic tank and a drilled well that is waterproof?
Ans: 50 ft (15 meters) according to the Regulation respecting waste
water disposal systems for isolated dwellings (Q-2, r.22).
(E) Explain the difference between "wastewater" and "grey water" as
defined in Quebec regulations. Ans: Wastewater includes all water
discharged from toilets and plumbing fixtures, while grey water
specifically refers to water from bathtubs, showers, sinks and appliances
excluding toilet water.
(M) When is an engineer required to design a wastewater treatment
system in Quebec? Ans: An engineer is required when the system
exceeds 3,240 liters/day capacity or when the system is for buildings
other than a residence.
(D) Which regulatory body certifies wastewater treatment systems in
Quebec, and what standards apply to autonomous sewage systems?
Ans: The Bureau de normalisation du Québec (BNQ), with standards
including NQ 3680-910 for septic tanks and NQ 3680-920 for advanced
treatment systems.
(E) What is a "leaching field" in the context of wastewater treatment?
Ans: A drainage area where effluent from the septic tank is distributed
through perforated pipes in trenches filled with stone and covered with
soil to allow for natural filtration and bacterial decomposition.
, Page | 2
(M) What is the purpose of a "pre-filter" in a septic system? Ans: A pre-
filter prevents solids from leaving the septic tank and entering the
leaching field, extending the life of the absorption system and reducing
the risk of clogging.
(E) What factors determine the size of a septic tank in a residential
installation? Ans: The number of bedrooms in the home, daily
wastewater volume, and local regulatory requirements as specified in Q-
2, r.22.
(D) Identify three types of advanced secondary treatment systems
permitted in Quebec. Ans: Biofiltration, sequencing batch reactor (SBR),
and attached growth aerobic treatment units as certified by BNQ
standards for residential use.
(M) What are the three main components of a typical autonomous
sewage system for a single-family home? Ans: A septic tank, a
distribution box, and a soil absorption system (leaching field or other
approved infiltration system).
(E) What is the primary function of a pump chamber in a wastewater
treatment system? Ans: To collect and pump effluent to a treatment
component or disposal field located at a higher elevation when gravity
flow is not possible.
(M) What is a "polishing field" in the context of wastewater treatment
systems? Ans: A secondary soil absorption system that receives pre-
treated effluent from an advanced treatment unit for final filtration before
returning to the environment.
(D) In what soil conditions would a mound system be recommended over
a conventional leaching field? Ans: When there is insufficient soil depth
above bedrock or groundwater table, or when percolation rates are either
too fast or too slow for conventional systems.
(E) What is the purpose of a distribution box in a wastewater treatment
system? Ans: To ensure equal distribution of effluent from the septic
tank to all lines of the leaching field.
, Page | 3
(M) What is the typical lifespan of a properly maintained conventional
septic system in Quebec? Ans: 25-30 years for the tank and 15-25 years
for the leaching field, depending on usage patterns and soil conditions.
(M) According to Q-2, r.22, what is the minimum horizontal distance
required between a septic tank and a building? Ans: 5 ft (1.5 meters) as
specified in the Regulation respecting waste water disposal systems for
isolated dwellings.
(D) Under what circumstances can a Quebec municipality grant a waiver
to the requirements of Q-2, r.22? Ans: Municipalities cannot grant
waivers to Q-2, r.22 as it is a provincial regulation; all installations must
comply with the minimum requirements with no exceptions permitted.
(E) Who is responsible for enforcing the Regulation respecting waste
water disposal systems for isolated dwellings in Quebec? Ans: The local
municipality is responsible for enforcement, including issuing permits and
inspecting installations.
(M) What information must be included in a site evaluation report for a
wastewater treatment system? Ans: Soil type and permeability, depth to
groundwater or bedrock, lot dimensions, topography, locations of wells
and water bodies, and percolation test results.
(M) What is the principle of hierarchization in Q-2, r.22 as it relates to the
selection of treatment systems? Ans: The regulation requires selecting
systems in order of preference: conventional leaching field first, then
modified leaching field, followed by other systems based on site
constraints.
(D) According to Quebec regulations, what documentation must an
installer provide to a property owner upon completion of a sewage
treatment system? Ans: As-built plans showing the location of all
components, manufacturer's operation and maintenance guidelines, and
any specific system warranty information.
(E) What permit is required before installing a residential wastewater
treatment system in Quebec? Ans: A municipal permit is required under
Q-2, r.22 before any work can begin on installing a new system or
modifying an existing one.
, Page | 4
(M) What is the minimum soil depth required for a conventional
absorption field according to Q-2, r.22? Ans: 4 ft (1.2 meters) of
permeable soil above the groundwater table, impermeable layer, or
bedrock.
(D) What are the maintenance requirements for an advanced secondary
treatment system under Quebec regulations? Ans: Annual professional
inspection, following manufacturer's maintenance schedule, and
maintaining a valid maintenance contract with a qualified service
provider.
(E) What is a "bench mark" in the context of a septic system installation?
Ans: A fixed reference point with a known elevation used as a starting
point for taking level measurements throughout the installation process.
(M) What information must be included in the municipal permit
application for a sewage treatment system? Ans: Site plan, soil analysis
results, system design specifications, property information, projected
wastewater volume, and name of the licensed contractor performing the
installation.
(D) How does Quebec's Environmental Quality Act (LRQ, c. Q-2) apply to
septic systems for isolated dwellings? Ans: It establishes the legal
framework prohibiting discharge of untreated wastewater and authorizes
the regulation (Q-2, r.22) that sets specific requirements for treatment
systems.
(E) What are the minimum setback distances between a leaching field
and a water well according to Q-2, r.22? Ans: 100 ft (30 meters) from a
drilled well and 98 ft (30 meters) from a dug well.
(M) How frequently must septic tanks be inspected according to Quebec
regulations? Ans: Every 2 years for year-round residences and every 4
years for seasonal residences.
(D) Under what conditions is a tertiary treatment system required for an
isolated dwelling in Quebec? Ans: When effluent must be discharged to a
surface water body or when site constraints prevent the installation of all
other treatment options listed in Q-2, r.22.
2.4 - CONTRACTOR – PRIVATE SEWERAGE
SYSTEMS QUESTIONS WITH DETAILED
VERIFIED ANSWERS
(E) What is the primary purpose of a septic tank in a sewage treatment
system? Ans: To separate solid waste from liquid effluent through
sedimentation and flotation, allowing clarified effluent to flow to the
leaching field.
(M) According to Quebec regulations, what is the minimum required
distance between a septic tank and a drilled well that is waterproof?
Ans: 50 ft (15 meters) according to the Regulation respecting waste
water disposal systems for isolated dwellings (Q-2, r.22).
(E) Explain the difference between "wastewater" and "grey water" as
defined in Quebec regulations. Ans: Wastewater includes all water
discharged from toilets and plumbing fixtures, while grey water
specifically refers to water from bathtubs, showers, sinks and appliances
excluding toilet water.
(M) When is an engineer required to design a wastewater treatment
system in Quebec? Ans: An engineer is required when the system
exceeds 3,240 liters/day capacity or when the system is for buildings
other than a residence.
(D) Which regulatory body certifies wastewater treatment systems in
Quebec, and what standards apply to autonomous sewage systems?
Ans: The Bureau de normalisation du Québec (BNQ), with standards
including NQ 3680-910 for septic tanks and NQ 3680-920 for advanced
treatment systems.
(E) What is a "leaching field" in the context of wastewater treatment?
Ans: A drainage area where effluent from the septic tank is distributed
through perforated pipes in trenches filled with stone and covered with
soil to allow for natural filtration and bacterial decomposition.
, Page | 2
(M) What is the purpose of a "pre-filter" in a septic system? Ans: A pre-
filter prevents solids from leaving the septic tank and entering the
leaching field, extending the life of the absorption system and reducing
the risk of clogging.
(E) What factors determine the size of a septic tank in a residential
installation? Ans: The number of bedrooms in the home, daily
wastewater volume, and local regulatory requirements as specified in Q-
2, r.22.
(D) Identify three types of advanced secondary treatment systems
permitted in Quebec. Ans: Biofiltration, sequencing batch reactor (SBR),
and attached growth aerobic treatment units as certified by BNQ
standards for residential use.
(M) What are the three main components of a typical autonomous
sewage system for a single-family home? Ans: A septic tank, a
distribution box, and a soil absorption system (leaching field or other
approved infiltration system).
(E) What is the primary function of a pump chamber in a wastewater
treatment system? Ans: To collect and pump effluent to a treatment
component or disposal field located at a higher elevation when gravity
flow is not possible.
(M) What is a "polishing field" in the context of wastewater treatment
systems? Ans: A secondary soil absorption system that receives pre-
treated effluent from an advanced treatment unit for final filtration before
returning to the environment.
(D) In what soil conditions would a mound system be recommended over
a conventional leaching field? Ans: When there is insufficient soil depth
above bedrock or groundwater table, or when percolation rates are either
too fast or too slow for conventional systems.
(E) What is the purpose of a distribution box in a wastewater treatment
system? Ans: To ensure equal distribution of effluent from the septic
tank to all lines of the leaching field.
, Page | 3
(M) What is the typical lifespan of a properly maintained conventional
septic system in Quebec? Ans: 25-30 years for the tank and 15-25 years
for the leaching field, depending on usage patterns and soil conditions.
(M) According to Q-2, r.22, what is the minimum horizontal distance
required between a septic tank and a building? Ans: 5 ft (1.5 meters) as
specified in the Regulation respecting waste water disposal systems for
isolated dwellings.
(D) Under what circumstances can a Quebec municipality grant a waiver
to the requirements of Q-2, r.22? Ans: Municipalities cannot grant
waivers to Q-2, r.22 as it is a provincial regulation; all installations must
comply with the minimum requirements with no exceptions permitted.
(E) Who is responsible for enforcing the Regulation respecting waste
water disposal systems for isolated dwellings in Quebec? Ans: The local
municipality is responsible for enforcement, including issuing permits and
inspecting installations.
(M) What information must be included in a site evaluation report for a
wastewater treatment system? Ans: Soil type and permeability, depth to
groundwater or bedrock, lot dimensions, topography, locations of wells
and water bodies, and percolation test results.
(M) What is the principle of hierarchization in Q-2, r.22 as it relates to the
selection of treatment systems? Ans: The regulation requires selecting
systems in order of preference: conventional leaching field first, then
modified leaching field, followed by other systems based on site
constraints.
(D) According to Quebec regulations, what documentation must an
installer provide to a property owner upon completion of a sewage
treatment system? Ans: As-built plans showing the location of all
components, manufacturer's operation and maintenance guidelines, and
any specific system warranty information.
(E) What permit is required before installing a residential wastewater
treatment system in Quebec? Ans: A municipal permit is required under
Q-2, r.22 before any work can begin on installing a new system or
modifying an existing one.
, Page | 4
(M) What is the minimum soil depth required for a conventional
absorption field according to Q-2, r.22? Ans: 4 ft (1.2 meters) of
permeable soil above the groundwater table, impermeable layer, or
bedrock.
(D) What are the maintenance requirements for an advanced secondary
treatment system under Quebec regulations? Ans: Annual professional
inspection, following manufacturer's maintenance schedule, and
maintaining a valid maintenance contract with a qualified service
provider.
(E) What is a "bench mark" in the context of a septic system installation?
Ans: A fixed reference point with a known elevation used as a starting
point for taking level measurements throughout the installation process.
(M) What information must be included in the municipal permit
application for a sewage treatment system? Ans: Site plan, soil analysis
results, system design specifications, property information, projected
wastewater volume, and name of the licensed contractor performing the
installation.
(D) How does Quebec's Environmental Quality Act (LRQ, c. Q-2) apply to
septic systems for isolated dwellings? Ans: It establishes the legal
framework prohibiting discharge of untreated wastewater and authorizes
the regulation (Q-2, r.22) that sets specific requirements for treatment
systems.
(E) What are the minimum setback distances between a leaching field
and a water well according to Q-2, r.22? Ans: 100 ft (30 meters) from a
drilled well and 98 ft (30 meters) from a dug well.
(M) How frequently must septic tanks be inspected according to Quebec
regulations? Ans: Every 2 years for year-round residences and every 4
years for seasonal residences.
(D) Under what conditions is a tertiary treatment system required for an
isolated dwelling in Quebec? Ans: When effluent must be discharged to a
surface water body or when site constraints prevent the installation of all
other treatment options listed in Q-2, r.22.
