CRSS PRACTICE TEST 2026 QUESTIONS WITH
ANSWERS GRADED A+
▶ Soil suitability factors include: _________, ________, and _________.?
Answer:soil texture, soil depth, and restrictive horizon
▶ Overall site suitability factors include ________, ________,
___________, and ____________.? Answer:site factor, soil factors,
groundwater evaluation, and surface drainage analysis
▶ A common reason for wastewater system failure is __________.?
Answer:hydraulic overloading (due to modernized tank usually)
▶ The value Q is? Answer:Quantity of Sewage (GPD)
▶ Some malfunctioning OSSF can be made to function properly with
minimal cost by implementing ______________.? Answer:water
conservation measures.
▶ In estimating water usage for a single-family dwelling, the number of
_________ in the home is a key indicator; however, _________ should
also be considered.? Answer:bedrooms, square footage
▶ List four water saving plumbing devices that can be used in a home.?
Answer:low flow toilets, low flow shower head, low flow faucets, pressure
reducing valves
▶ Identify four water-saving habits homeowners should adopt?
Answer:don't leave water running, full laundry and dishwasher loads,
reduce/eliminate use of garbage disposals, not using toilet for trash
disposal
▶ Two wastewater tests commonly used to measure the strength of
sewage are the ________ test and the ________ test.? Answer:BOD, TSS
▶ The minimum water usage rate that should be used for planning an
OSSF for a new home with three bedrooms and 3000 square feet of interior
living area is _______ gallons/day.? Answer:300
,▶ Blockage in the home plumbing system is often caused by _______,
________, and _________.? Answer:oils, greases, and fats
▶ It is recommended that _____________ are not used because they
significantly increase the amount of suspended solids and organic matter
that is discharged to sewage disposal system.? Answer:garbage disposal
▶ Several samples were taken from a small washateria with seven new
water-conserving machines and sent to a lab for BOD analysis. The
average BOD was 406 mg/L. What would be the minimum expected BOD
(organic) loading in lbs./day?? Answer:4.74 lbs/day
▶ Would a treatment plant capable of handling 1500 gallons per day of
wastewater with BOD as high as 280 mg/L be capable of handling
wastewater from the above washateria? What is the organic loading
capacity of this treatment plant?? Answer:3.50 lbs/day
▶ What is the loading rate of a system with: Q= 550GPD, BOD= 350 mg/L,
Ph=8.4, TSS= 400 mg/L? Answer:1.6 lbs/day
▶ The most commonly use primary treatment component in Texas for on-
site systems is the? Answer:septic tank
▶ Which of the following produces the highest quality effluent??
Answer:city sewage treatment plant
▶ what is the purpose of the inlet baffle or T?? Answer:Reduce velocity
and disperse flow, vent the tank to the building plumbing
▶ The minimum distances a watertight sewage treatment tank should be
from a water-well and a property line are? Answer:50 feet and 5 feet
respectively
▶ which of the following is true regarding septic tanks?? Answer:The must
have two- or three-compartments
▶ A septic tank serving a new five-bedroom home with 3800 sqft must
have a minimum capacity of? Answer:1,250 gallons
, ▶ Of what materials may a septic tank be constructed?? Answer:steel
reinforced concrete
▶ The expected volume of wastewater (Q) in gal/day from an older (pre-
1990) three-bedroom mobile home would be? Answer:300
▶ Which of the following characteristics should a poured-in-place concrete
septic tanks have?? Answer:watertight, designed by PE, Structurally sound
▶ The standard inlet and outlet devices in a septic tank should be?
Answer:tees
▶ Properly sealed septic tanks are? Answer:vented through the building
plumbing
▶ The liquid depth of a septic tank? Answer:must be at least 30 inches
▶ Which of the following is true of a septic tank with 15 inches of cover??
Answer:it must have an access port with a riser
▶ Which if the following is acceptable for the line from the building to the
treatment tank?? Answer:cast iron, SDR 26 plastic pipe, and Schedule 40
plastic pipe
▶ Most of the settable solids and scum that enter a properly designed
septic tank will be? Answer:removed in the first compartment
▶ Which of the following should a house sewer have?? Answer:A two way
sanitary clean-out, minimum 1/8 inch per foot fall, minimum diameter of 3
inches
▶ Which of the following applies if effluent is to be pumped?? Answer:A
high-water alarm must be provided, the pump must be installed in a
separate chamber, a check valve should be in line if the disposal area is
upgrade
▶ T/F: Septic tanks may be 1.5 inch-thick steel? Answer:F
▶ T/F: Septic tanks may be reinforced fiberglass? Answer:T
ANSWERS GRADED A+
▶ Soil suitability factors include: _________, ________, and _________.?
Answer:soil texture, soil depth, and restrictive horizon
▶ Overall site suitability factors include ________, ________,
___________, and ____________.? Answer:site factor, soil factors,
groundwater evaluation, and surface drainage analysis
▶ A common reason for wastewater system failure is __________.?
Answer:hydraulic overloading (due to modernized tank usually)
▶ The value Q is? Answer:Quantity of Sewage (GPD)
▶ Some malfunctioning OSSF can be made to function properly with
minimal cost by implementing ______________.? Answer:water
conservation measures.
▶ In estimating water usage for a single-family dwelling, the number of
_________ in the home is a key indicator; however, _________ should
also be considered.? Answer:bedrooms, square footage
▶ List four water saving plumbing devices that can be used in a home.?
Answer:low flow toilets, low flow shower head, low flow faucets, pressure
reducing valves
▶ Identify four water-saving habits homeowners should adopt?
Answer:don't leave water running, full laundry and dishwasher loads,
reduce/eliminate use of garbage disposals, not using toilet for trash
disposal
▶ Two wastewater tests commonly used to measure the strength of
sewage are the ________ test and the ________ test.? Answer:BOD, TSS
▶ The minimum water usage rate that should be used for planning an
OSSF for a new home with three bedrooms and 3000 square feet of interior
living area is _______ gallons/day.? Answer:300
,▶ Blockage in the home plumbing system is often caused by _______,
________, and _________.? Answer:oils, greases, and fats
▶ It is recommended that _____________ are not used because they
significantly increase the amount of suspended solids and organic matter
that is discharged to sewage disposal system.? Answer:garbage disposal
▶ Several samples were taken from a small washateria with seven new
water-conserving machines and sent to a lab for BOD analysis. The
average BOD was 406 mg/L. What would be the minimum expected BOD
(organic) loading in lbs./day?? Answer:4.74 lbs/day
▶ Would a treatment plant capable of handling 1500 gallons per day of
wastewater with BOD as high as 280 mg/L be capable of handling
wastewater from the above washateria? What is the organic loading
capacity of this treatment plant?? Answer:3.50 lbs/day
▶ What is the loading rate of a system with: Q= 550GPD, BOD= 350 mg/L,
Ph=8.4, TSS= 400 mg/L? Answer:1.6 lbs/day
▶ The most commonly use primary treatment component in Texas for on-
site systems is the? Answer:septic tank
▶ Which of the following produces the highest quality effluent??
Answer:city sewage treatment plant
▶ what is the purpose of the inlet baffle or T?? Answer:Reduce velocity
and disperse flow, vent the tank to the building plumbing
▶ The minimum distances a watertight sewage treatment tank should be
from a water-well and a property line are? Answer:50 feet and 5 feet
respectively
▶ which of the following is true regarding septic tanks?? Answer:The must
have two- or three-compartments
▶ A septic tank serving a new five-bedroom home with 3800 sqft must
have a minimum capacity of? Answer:1,250 gallons
, ▶ Of what materials may a septic tank be constructed?? Answer:steel
reinforced concrete
▶ The expected volume of wastewater (Q) in gal/day from an older (pre-
1990) three-bedroom mobile home would be? Answer:300
▶ Which of the following characteristics should a poured-in-place concrete
septic tanks have?? Answer:watertight, designed by PE, Structurally sound
▶ The standard inlet and outlet devices in a septic tank should be?
Answer:tees
▶ Properly sealed septic tanks are? Answer:vented through the building
plumbing
▶ The liquid depth of a septic tank? Answer:must be at least 30 inches
▶ Which of the following is true of a septic tank with 15 inches of cover??
Answer:it must have an access port with a riser
▶ Which if the following is acceptable for the line from the building to the
treatment tank?? Answer:cast iron, SDR 26 plastic pipe, and Schedule 40
plastic pipe
▶ Most of the settable solids and scum that enter a properly designed
septic tank will be? Answer:removed in the first compartment
▶ Which of the following should a house sewer have?? Answer:A two way
sanitary clean-out, minimum 1/8 inch per foot fall, minimum diameter of 3
inches
▶ Which of the following applies if effluent is to be pumped?? Answer:A
high-water alarm must be provided, the pump must be installed in a
separate chamber, a check valve should be in line if the disposal area is
upgrade
▶ T/F: Septic tanks may be 1.5 inch-thick steel? Answer:F
▶ T/F: Septic tanks may be reinforced fiberglass? Answer:T
