IL SEPTIC INSTALLERS MIDTERM EXAM
QUESTIONS SOLVED CORRECTLY.
Public Sewer Connection - Answer Private residence must connect if w/in 300' or for any commercial
bldg. w/in 300' that has flows less than 1500 gpd. Commercial w/ flows = to or greater than 1500 gpd
must connect if sewer is w/in 1000'.
Unless physical barrier, ordinance, or cannot be done w/ individual line (4" line)-then PSD system is OK.
Acceptable Pipe Materials - Answer Vitrified clay, ductile iron, or plastic.
Anything after the tank or from distribution box has to be vitrified clay or plastic.
Schedule 40 or Greater - Answer under roads, driveways, or parking areas
Gravity Slope - Answer Diameter: 4" pipe + min. slope of 12" per 100'
Building sewers in excess of 50' should have what? - Answer A C/O @ least every 50' from building to
tank, distribution box, or ATU
Creviced Limestone Formation - Answer SS system cannot be installed where bottom of system is less
than 4' from top of limestone
If limestone is known to be present a soil test must be done @ least 4' deeper than where the bottom of
the trench will be
How far away can quick disconnect be? - Answer no more than 50' away from the device & w/in sight
of
Experimental Use Permits - Answer min. of 10 experimental systems installed b4 unconditional
approval granted. Permit valid for 2 yrs & evaluated @ end of 2 yrs.
,2 options for garbage grinders - Answer 1. solids retention tank btwn WW source & septic tk. for
kitchen waste only. Needs to be 50% of the size of the designed septic tank w/ a min. of 500 gals.
2. A septic tank receiving all flows sized as 50% of the septic tank size + septic tank size. i.e., septic tk =
1500 gals. /2 = 750 + 1500 = 2250 (would need 2500 gal tk)
How long should a homeowner keep maint. records for their system? - Answer the life of the system
When should the 1st maintenance of a septic tank after installation be completed for a residence? -
Answer Prior to or within 3 yrs. After initial inspection it can be done once every 5 yrs. Can be done by
everyone + homeowner
If sludge layer /suspended solids are greater than 33% . . . - Answer Must pump tank and perform
maintenance
When should a septic system be evaluated initially after installation for a non-residential bldg? - Answer
prior to or w/in 3 yrs. After that it should be done @ least every 3 yrs.
Owner cannot do. has to be engineer, env. health practitioner, member of dept, HD, or septic contractor
Aerobic Treatment Unit Evaluations - Answer 1 every 6 mos @ least (same ppl) + HOMEOWNER as long
as they follow manufacturer's requirements & proper maintenance
What is the maint. schedule for SFs & WSPs w/ surface discharges? - Answer @ least 1 per yr. + H.O. if
rules r followed. Pumped when solids & scum greater than 33%
Can a H.O. install & maintain a septic system on his/her property? - Answer Yes
Who can perform the excavation for a septic system? - Answer A licensed installer (employee while
supervised) or the property owner.
What is the min. size tank for flows UP TO 500 gpd? - Answer 750 gals.
, If flows are greater than 500 gpd, how do you size the tank? - Answer Tank size should be = to @ least
1.5x the estimated sewage flow
How do you size a tank(s) for flows greater than 1350 gpd? - Answer U must use multiple tks. in a series
or multiple compartment tks. where the 1st tank or the 1st comp. in a multicomp. tk. is 1/2-2/3 of the
total required capacity. of the tank(s)
How do you size the tank for a raised filter bed for a residence? - Answer It has to be an NSF 40 batch
treatment system. The aeration tank has to be 2x the daily flow
How do you size the tank for a RFB for a commercial bldg? - Answer The aeration tk. has to be 3x the
daily flow.
Multiple tanks in a series connected @ btm for flow equalization can be used
How are RFB sidewalls sized? - Answer 3:1 ratio
How are distribution lines for RFBs? - Answer 4" perforated pipe on 15" centers
Describe a RFB mantle - Answer Mantle must go in 6" deep to original soil. Torpedo sand depth is 12"
ttl. (0.5-2.0). Sand filter media depth is 30".
What is the maximum size a RFB can be? - Answer A RFB cannot exceed 600 sq. ft. If more area is
needed you must use multiple beds sharing a common mantle separated by 15'
What filter loading rate do you use to size RFBs? - Answer For a residence with a flow of 1500 gpd or
less, use a filter loading rate of 4 gals per sq ft per day
For a commerical bldg. (or residence with flows greater than 1500 gpd), how do u size a RFB? - Answer
Use a filter loading rate of 2.5 gals per sq ft per day for comm. bldgs. of any size or residences w/ flows
greater than 1500
QUESTIONS SOLVED CORRECTLY.
Public Sewer Connection - Answer Private residence must connect if w/in 300' or for any commercial
bldg. w/in 300' that has flows less than 1500 gpd. Commercial w/ flows = to or greater than 1500 gpd
must connect if sewer is w/in 1000'.
Unless physical barrier, ordinance, or cannot be done w/ individual line (4" line)-then PSD system is OK.
Acceptable Pipe Materials - Answer Vitrified clay, ductile iron, or plastic.
Anything after the tank or from distribution box has to be vitrified clay or plastic.
Schedule 40 or Greater - Answer under roads, driveways, or parking areas
Gravity Slope - Answer Diameter: 4" pipe + min. slope of 12" per 100'
Building sewers in excess of 50' should have what? - Answer A C/O @ least every 50' from building to
tank, distribution box, or ATU
Creviced Limestone Formation - Answer SS system cannot be installed where bottom of system is less
than 4' from top of limestone
If limestone is known to be present a soil test must be done @ least 4' deeper than where the bottom of
the trench will be
How far away can quick disconnect be? - Answer no more than 50' away from the device & w/in sight
of
Experimental Use Permits - Answer min. of 10 experimental systems installed b4 unconditional
approval granted. Permit valid for 2 yrs & evaluated @ end of 2 yrs.
,2 options for garbage grinders - Answer 1. solids retention tank btwn WW source & septic tk. for
kitchen waste only. Needs to be 50% of the size of the designed septic tank w/ a min. of 500 gals.
2. A septic tank receiving all flows sized as 50% of the septic tank size + septic tank size. i.e., septic tk =
1500 gals. /2 = 750 + 1500 = 2250 (would need 2500 gal tk)
How long should a homeowner keep maint. records for their system? - Answer the life of the system
When should the 1st maintenance of a septic tank after installation be completed for a residence? -
Answer Prior to or within 3 yrs. After initial inspection it can be done once every 5 yrs. Can be done by
everyone + homeowner
If sludge layer /suspended solids are greater than 33% . . . - Answer Must pump tank and perform
maintenance
When should a septic system be evaluated initially after installation for a non-residential bldg? - Answer
prior to or w/in 3 yrs. After that it should be done @ least every 3 yrs.
Owner cannot do. has to be engineer, env. health practitioner, member of dept, HD, or septic contractor
Aerobic Treatment Unit Evaluations - Answer 1 every 6 mos @ least (same ppl) + HOMEOWNER as long
as they follow manufacturer's requirements & proper maintenance
What is the maint. schedule for SFs & WSPs w/ surface discharges? - Answer @ least 1 per yr. + H.O. if
rules r followed. Pumped when solids & scum greater than 33%
Can a H.O. install & maintain a septic system on his/her property? - Answer Yes
Who can perform the excavation for a septic system? - Answer A licensed installer (employee while
supervised) or the property owner.
What is the min. size tank for flows UP TO 500 gpd? - Answer 750 gals.
, If flows are greater than 500 gpd, how do you size the tank? - Answer Tank size should be = to @ least
1.5x the estimated sewage flow
How do you size a tank(s) for flows greater than 1350 gpd? - Answer U must use multiple tks. in a series
or multiple compartment tks. where the 1st tank or the 1st comp. in a multicomp. tk. is 1/2-2/3 of the
total required capacity. of the tank(s)
How do you size the tank for a raised filter bed for a residence? - Answer It has to be an NSF 40 batch
treatment system. The aeration tank has to be 2x the daily flow
How do you size the tank for a RFB for a commercial bldg? - Answer The aeration tk. has to be 3x the
daily flow.
Multiple tanks in a series connected @ btm for flow equalization can be used
How are RFB sidewalls sized? - Answer 3:1 ratio
How are distribution lines for RFBs? - Answer 4" perforated pipe on 15" centers
Describe a RFB mantle - Answer Mantle must go in 6" deep to original soil. Torpedo sand depth is 12"
ttl. (0.5-2.0). Sand filter media depth is 30".
What is the maximum size a RFB can be? - Answer A RFB cannot exceed 600 sq. ft. If more area is
needed you must use multiple beds sharing a common mantle separated by 15'
What filter loading rate do you use to size RFBs? - Answer For a residence with a flow of 1500 gpd or
less, use a filter loading rate of 4 gals per sq ft per day
For a commerical bldg. (or residence with flows greater than 1500 gpd), how do u size a RFB? - Answer
Use a filter loading rate of 2.5 gals per sq ft per day for comm. bldgs. of any size or residences w/ flows
greater than 1500
