Designated Representative OSSF (Latest
Update ) Questions with
Correct Answers {Grade A} 100% Verified
A minimum of ___ of sand, sandy loam, clay loam, or pea gravel shall be placed under
and around all tanks - correct answer 4"
Tank excavations must be backfilled with soil or pea gravel that is free of rock larger
than - correct answer 1/2" diameter
Standard Absorptive Drainfield - correct answer suitable soil, perforated pipe and
porous media (commonly gravel) are placed, usually trenches 2'-3' wide, inexpensive
The size of any drainfield needed depends on two factors: - correct answer
Wastewater loading (Q), and Long-term soil acceptance rate (Ra) determined by soil
class.
,Solid pipe from treatment tank to drainfield must be - correct answer minimum of 3"
wide SDR35 or stronger, minimum of 5" in length, and maintain continuous fall,
minimum depth is 18"
Maximum depth of drainfield is - correct answer 3' except for west Texas (5')
Minimum depth and width - correct answer 18"
Minimum separations between trenches or excavations is - correct answer 3'
undisturbed earth
Bottom of excavation must be level to - correct answer 1" per 25' or within 3" of entire
excavation (whichever is less)
The bottom and sidewalls of excavation in drainfield should be - correct answer
scarified or raked out to remove smeared or compacted soil
Minimum depth of porous media in drainfield - correct answer 12" with 6" under pipe
,Porous media must be between - correct answer .75" to 2" and resistant to chemical
reaction *exception for tire chips of double-strength geotextile fabric which can be 3"*
Drainlines shall consist of perforated pipe installed with - correct answer perforations
below center and a maximum single-line length of 150'
In excavations more than 4' wide - correct answer drainlines should be within 2' of
sides and with a max of 4' between parallel lines
Permeable soil barrier - correct answer must be placed between top of porous media
and excavation backfill, can be geotextile fabric
Evapotranspiration (ET) Drainfield - correct answer sandy loam beds, porous media,
distribution pipe, must be covered with vegetation, may be lined or unlined
, Lined ET bed - correct answer used where shallow groundwater exists, all wastewater
is disposed of by evaporation or transpiration. Requires Installer II. Lingers may be
concrete, compacted and tested clay, or commonly 20mil or thicker plastic
Unlined ET bed - correct answer used where soils are highly impermeable, such as
Class IV, and seasonal groundwater will not enter bed, Wastewater is disposed by
evaporation, transpiration, and soil absorption. Referred to as ETA system. Can use
Installer I. Local evaporation must exceed rainfall
In ET systems, affidavit of what is required - correct answer Quantity of wastewater
(Q) permitted, must use water-saving devices
Construction requirements for ET - correct answer -Must have two or more
alternating ET fields separated by control valve
-Backfill must be Class II sandy loam
-Porous media must extend at least 1' beyond each drainline horizontally
-must be mounded so water will not pool over the top of system
Update ) Questions with
Correct Answers {Grade A} 100% Verified
A minimum of ___ of sand, sandy loam, clay loam, or pea gravel shall be placed under
and around all tanks - correct answer 4"
Tank excavations must be backfilled with soil or pea gravel that is free of rock larger
than - correct answer 1/2" diameter
Standard Absorptive Drainfield - correct answer suitable soil, perforated pipe and
porous media (commonly gravel) are placed, usually trenches 2'-3' wide, inexpensive
The size of any drainfield needed depends on two factors: - correct answer
Wastewater loading (Q), and Long-term soil acceptance rate (Ra) determined by soil
class.
,Solid pipe from treatment tank to drainfield must be - correct answer minimum of 3"
wide SDR35 or stronger, minimum of 5" in length, and maintain continuous fall,
minimum depth is 18"
Maximum depth of drainfield is - correct answer 3' except for west Texas (5')
Minimum depth and width - correct answer 18"
Minimum separations between trenches or excavations is - correct answer 3'
undisturbed earth
Bottom of excavation must be level to - correct answer 1" per 25' or within 3" of entire
excavation (whichever is less)
The bottom and sidewalls of excavation in drainfield should be - correct answer
scarified or raked out to remove smeared or compacted soil
Minimum depth of porous media in drainfield - correct answer 12" with 6" under pipe
,Porous media must be between - correct answer .75" to 2" and resistant to chemical
reaction *exception for tire chips of double-strength geotextile fabric which can be 3"*
Drainlines shall consist of perforated pipe installed with - correct answer perforations
below center and a maximum single-line length of 150'
In excavations more than 4' wide - correct answer drainlines should be within 2' of
sides and with a max of 4' between parallel lines
Permeable soil barrier - correct answer must be placed between top of porous media
and excavation backfill, can be geotextile fabric
Evapotranspiration (ET) Drainfield - correct answer sandy loam beds, porous media,
distribution pipe, must be covered with vegetation, may be lined or unlined
, Lined ET bed - correct answer used where shallow groundwater exists, all wastewater
is disposed of by evaporation or transpiration. Requires Installer II. Lingers may be
concrete, compacted and tested clay, or commonly 20mil or thicker plastic
Unlined ET bed - correct answer used where soils are highly impermeable, such as
Class IV, and seasonal groundwater will not enter bed, Wastewater is disposed by
evaporation, transpiration, and soil absorption. Referred to as ETA system. Can use
Installer I. Local evaporation must exceed rainfall
In ET systems, affidavit of what is required - correct answer Quantity of wastewater
(Q) permitted, must use water-saving devices
Construction requirements for ET - correct answer -Must have two or more
alternating ET fields separated by control valve
-Backfill must be Class II sandy loam
-Porous media must extend at least 1' beyond each drainline horizontally
-must be mounded so water will not pool over the top of system
