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 O - Water Supply Fixture Units (WSFU) for a Supply System with Flushometer Water Closets
WSFU |
Demand (GPM) |
Pipe Size (Inches) |
Pressure Loss (PSI/100' of Pipe) |
Velocity (Ft./Sec.) |
Meter Size (Inches) |
10 |
27 |
11/4" |
8.3 |
6.8 |
3/4" |
12 |
28.6 |
11/4" |
9.2 |
7.2 |
3/4" |
14 |
30.2 |
11/4" |
10 |
7.9 |
3/4" |
16 |
31.8 |
11/4" |
11 |
8.0 |
3/4" |
20 |
35 |
11/2" |
6.0 |
6.4 |
3/4" |
25 |
38 |
11/2" |
7.0 |
6.9 |
1" |
30 |
41 |
11/2" |
8.0 |
7.4 |
1" |
35 |
43.8 |
11/2" |
8.8 |
8.0 |
1" |
40 |
46.5 |
2" |
2.5 |
4.7 |
1" |
45 |
49 |
2" |
2.7 |
5.1 |
1" |
50 |
51.5 |
2" |
2.9 |
5.4 |
11/2" |
60 |
55 |
2" |
3.4 |
5.8 |
11/2" |
70 |
58.5 |
2" |
3.7 |
6.0 |
11/2" |
80 |
62 |
2" |
4.0 |
6.2 |
11/2" |
90 |
64.8 |
2" |
4.6 |
6.5 |
11/2" |
100 |
67.5 |
2" |
5.0 |
6.8 |
11/2" |
120 |
72.5 |
2" |
5.6 |
7.2 |
2" |
140 |
77.5 |
2" |
6.3 |
8.0 |
2" |
160 |
82.5 |
21/2" |
2.7 |
5.7 |
2" |
180 |
87 |
21/2" |
3.0 |
6.1 |
2" |
200 |
91.5 |
21/2" |
3.4 |
6.4 |
2" |
225 |
97 |
21/2" |
3.7 |
6.8 |
2" |
250 |
101 |
21/2" |
4.0 |
7.1 |
3" |
275 |
106 |
21/2" |
4.2 |
7.3 |
3" |
300 |
110 |
21/2" |
4.6 |
7.6 |
3" |
350 |
119 |
3" |
2.1 |
5.5 |
3" |
400 |
126 |
3" |
2.3 |
5.9 |
3" |
450 |
138 |
3" |
2.7 |
6.3 |
3" |
500 |
145 |
3" |
3.0 |
6.8 |
3" |
600 |
160 |
3" |
3.6 |
7.4 |
4" |
750 |
178 |
4" |
1.1 |
4.7 |
4" |
1000 |
208 |
4" |
1.5 |
5.6 |
4" |
1250 |
240 |
4" |
1.9 |
6.4 |
4" |
1500 |
267 |
4" |
2.3 |
7.0 |
4" |
1750 |
294 |
4" |
2.8 |
7.8 |
4" |
2000 |
321 |
6" |
0.4 |
3.7 |
6" |
Agency Notes:
Where a unit of local government or the community public water supply does not require separate water service lines for irrigation or similar systems that are likely to impose continuous demands (e.g., lawn sprinkler or air conditioning systems), the following rule applies: estimate the continuous demand (in gallons per minute) for outlets/systems separately from the intermittent demand from the above fixtures, and add this amount to the demand of the fixtures (in gallons per minute).
Meter and meter yoke sizes shown in this table shall apply only to those jurisdictions or governmental units where local ordinances or community public water supply requirements do not prescribe specific sizes of meters or meter yokes. Where local ordinances or community public water supply requirements cover such sizing, those requirements shall be followed.