Illinois Administrative Code
Title 77 - PUBLIC HEALTH
Part 890 - ILLINOIS PLUMBING CODE
Subpart M - INSPECTIONS, TESTS, MAINTENANCE AND ADMINISTRATION
Appendix A - Plumbing Materials, Equipment, Use Restrictions and Applicable Standards
Table K - Size and Length of Vents

Universal Citation: 77 IL Admin Code § K
Current through Register Vol. 49, No. 13, March 28, 2025

Size of Soil or Waste Stack

Fixture Units Connected

Diameter of Vent Required (Inches)

11/4

11/2

2

21/2

3

4

5

6

8

Maximum Length of Vent (Feet)

11/4

2

30

11/2

8

50

150

11/2

10

30

100

2

12

30

75

200

2

20

26

50

150

21/2

42

30

100

300

3

10

30

100

200

600

3

30

60

200

500

3

60

50

60

400

4

100

35

100

260

1,000

4

200

30

90

250

900

4

500

20

70

180

700

5

200

35

80

350

1,000

5

500

30

70

300

900

5

1,100

20

50

200

700

6

350

25

50

200

400

1,300

6

620

15

30

125

300

1,100

6

960

24

100

250

1,000

6

1,900

20

70

200

700

8

600

50

150

500

1,300

8

1,400

40

100

400

1,200

8

2,200

30

80

350

1,100

9

3,600

25

60

250

800

10

1,000

75

125

1,000

10

2,500

50

100

500

10

3,800

30

80

350

10

5,600

25

60

250

Agency Note: Per Section 890.1580(e), no more than 20 percent of the maximum developed length may be installed in the horizontal position. Vent piping serving floor drains shall be installed in such a manner as to minimize horizontal vent distances.

Disclaimer: These regulations may not be the most recent version. Illinois may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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