IL SEPTIC INSTALLERS
Comprehensive Resource To Help You Ace 2026-2027 Exams
Includes Frequently Tested Questions With ELABORATED
100% Correct COMPLETE SOLUTIONS
Guaranteed Pass First Attempt!! Current Update
1. When should the 1st maintenance of a septic tank after installation be
completed for a residence? - Correct Answer: Prior to or within 3 yrs.
After initial inspection it can be done once every 5 yrs. Can be done by
everyone + homeowner
2. If sludge layer /suspended solids are greater than 33% . . . - Correct
Answer: Must pump tank and perform maintenance
3. When should a septic system be evaluated initially after installation for a
non-residential bldg? - Correct Answer: prior to or w/in 3 yrs. After that
it should be done @ least every 3 yrs.
4. Owner cannot do. has to be engineer, env. health practitioner, member of
dept, HD, or septic contractor
5. Aerobic Treatment Unit Evaluations - Correct Answer: 1 every 6 mos @
least (same ppl) + HOMEOWNER as long as they follow manufacturer's
requirements & proper maintenance
,6. What is the maint. schedule for SFs & WSPs w/ surface discharges? -
Correct Answer: @ least 1 per yr. + H.O. if rules r followed. Pumped when
solids & scum greater than 33%
7. Can a H.O. install & maintain a septic system on his/her property? -
Correct Answer: Yes
8. Who can perform the excavation for a septic system? - Correct Answer:
A licensed installer (employee while supervised) or the property owner.
9. What is the min. size tank for flows UP TO 500 gpd? - Correct Answer:
750 gals.
10.If flows are greater than 500 gpd, how do you size the tank? - Correct
Answer: Tank size should be = to @ least 1.5x the estimated sewage flow
11.How do you size a tank(s) for flows greater than 1350 gpd? - Correct
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)
12.How do you size the tank for a raised filter bed for a residence? -
Correct Answer: It has to be an NSF 40 batch treatment system. The
aeration tank has to be 2x the daily flow
,13.How do you size the tank for a RFB for a commercial bldg? - Correct
Answer: The aeration tk. has to be 3x the daily flow.
14.Multiple tanks in a series connected @ btm for flow equalization can be
used
15.How are RFB sidewalls sized? - Correct Answer: 3:1 ratio
16.How are distribution lines for RFBs? - Correct Answer: 4" perforated
pipe on 15" centers
17.Describe a RFB mantle - Correct 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".
18.What is the maximum size a RFB can be? - Correct 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'
19.What filter loading rate do you use to size RFBs? - Correct 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
20.For a commerical bldg. (or residence with flows greater than 1500 gpd),
how do u size a RFB? - Correct 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
21.A RFB mantle shall be at least.. - Correct Answer: = to the area of the
FB. Shall not be designed for perc rates that exceed 120 mins per inch.
22.The slope of the bottom of the mantle shall be level + or - ____ inch(es) -
Correct Answer: 1"
23.SHWT must be @ least 6" away from what & what do u have to add if it
isn't? - Correct Answer: RFB bottom. Add more sand.
24.How much larger does the bottom of a seepage bed have to be? -
Correct Answer: 1.5x what's determined by soil chart
25.What is the maximum CTC spacing for a seepage bed? - Correct Answer:
6' maximum spacing for distribution lines. = spaced
26.How far do distribution lines have to be from sidewalls (seepage bed & sand
filters)? - Correct Answer: 18"
27.What is the minimum daily flow a SF shall be based off of? - Correct
Answer: 100 gallons of waste per day
Comprehensive Resource To Help You Ace 2026-2027 Exams
Includes Frequently Tested Questions With ELABORATED
100% Correct COMPLETE SOLUTIONS
Guaranteed Pass First Attempt!! Current Update
1. When should the 1st maintenance of a septic tank after installation be
completed for a residence? - Correct Answer: Prior to or within 3 yrs.
After initial inspection it can be done once every 5 yrs. Can be done by
everyone + homeowner
2. If sludge layer /suspended solids are greater than 33% . . . - Correct
Answer: Must pump tank and perform maintenance
3. When should a septic system be evaluated initially after installation for a
non-residential bldg? - Correct Answer: prior to or w/in 3 yrs. After that
it should be done @ least every 3 yrs.
4. Owner cannot do. has to be engineer, env. health practitioner, member of
dept, HD, or septic contractor
5. Aerobic Treatment Unit Evaluations - Correct Answer: 1 every 6 mos @
least (same ppl) + HOMEOWNER as long as they follow manufacturer's
requirements & proper maintenance
,6. What is the maint. schedule for SFs & WSPs w/ surface discharges? -
Correct Answer: @ least 1 per yr. + H.O. if rules r followed. Pumped when
solids & scum greater than 33%
7. Can a H.O. install & maintain a septic system on his/her property? -
Correct Answer: Yes
8. Who can perform the excavation for a septic system? - Correct Answer:
A licensed installer (employee while supervised) or the property owner.
9. What is the min. size tank for flows UP TO 500 gpd? - Correct Answer:
750 gals.
10.If flows are greater than 500 gpd, how do you size the tank? - Correct
Answer: Tank size should be = to @ least 1.5x the estimated sewage flow
11.How do you size a tank(s) for flows greater than 1350 gpd? - Correct
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)
12.How do you size the tank for a raised filter bed for a residence? -
Correct Answer: It has to be an NSF 40 batch treatment system. The
aeration tank has to be 2x the daily flow
,13.How do you size the tank for a RFB for a commercial bldg? - Correct
Answer: The aeration tk. has to be 3x the daily flow.
14.Multiple tanks in a series connected @ btm for flow equalization can be
used
15.How are RFB sidewalls sized? - Correct Answer: 3:1 ratio
16.How are distribution lines for RFBs? - Correct Answer: 4" perforated
pipe on 15" centers
17.Describe a RFB mantle - Correct 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".
18.What is the maximum size a RFB can be? - Correct 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'
19.What filter loading rate do you use to size RFBs? - Correct 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
20.For a commerical bldg. (or residence with flows greater than 1500 gpd),
how do u size a RFB? - Correct 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
21.A RFB mantle shall be at least.. - Correct Answer: = to the area of the
FB. Shall not be designed for perc rates that exceed 120 mins per inch.
22.The slope of the bottom of the mantle shall be level + or - ____ inch(es) -
Correct Answer: 1"
23.SHWT must be @ least 6" away from what & what do u have to add if it
isn't? - Correct Answer: RFB bottom. Add more sand.
24.How much larger does the bottom of a seepage bed have to be? -
Correct Answer: 1.5x what's determined by soil chart
25.What is the maximum CTC spacing for a seepage bed? - Correct Answer:
6' maximum spacing for distribution lines. = spaced
26.How far do distribution lines have to be from sidewalls (seepage bed & sand
filters)? - Correct Answer: 18"
27.What is the minimum daily flow a SF shall be based off of? - Correct
Answer: 100 gallons of waste per day
