| Material | C factor |
| New Steel | 130-140 |
| Old Steel | 90-100 |
| PVC & CPVC | 140-150 |
| Cast Iron, New, unlined | 130 |
| 10 yrs old | 107-113 |
| 20 yrs old | 89-100 |
| 30 yrs old | 75-90 |
| 40 yrs old | 64-83 |
| Concrete lined | 120-140 |
| Formula f = 0.2083 * (100/C)^1.852 * (Q^1.852/Di^4.8655) | |
| f = ft/100 ft loss for water C = Hazen-Willams C factor Q = flowrate in GPM Di = pipe ID in inches |
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