PVC SDR 35 Sewer Pipe Sizes (ASTM D3034)
SDR 35 PVC is the green gravity sewer pipe used for most sanitary sewer laterals and mains, and it is common for storm drains as well. SDR (standard dimension ratio) is the outside diameter divided by the wall thickness, so a higher SDR means a thinner wall. This table gives the ASTM D3034 outside diameter and minimum wall thickness.
| Nominal sizein | Average outside diameterin | Minimum wall, SDR 35in | Approximate inside diameterin |
|---|---|---|---|
| 4 | 4.215 | 0.12 | 3.97 |
| 6 | 6.275 | 0.18 | 5.92 |
| 8 | 8.4 | 0.24 | 7.92 |
| 10 | 10.5 | 0.3 | 9.9 |
| 12 | 12.5 | 0.36 | 11.78 |
| 15 | 15.3 | 0.437 | 14.43 |
Notes
- SDR 35 pipe has a minimum pipe stiffness of 46 psi; SDR 26 (thicker wall) has 115 psi and is used for deeper or heavier-loaded installations.
- The approximate inside diameter is calculated from the average OD and minimum wall and is for reference; manufacturers publish the actual average ID.
- Sizes 18 in through 27 in are covered by ASTM F679, not D3034.
- SDR 35 is gravity pipe. Pressure water and force mains use different standards (for example AWWA C900).
Frequently asked questions
What is the outside diameter of 4 inch SDR 35 pipe?
The average outside diameter is 4.215 inches, with a minimum wall of 0.120 inch.
Is SDR 35 the same as Schedule 40?
No. Schedule 40 PVC is a pressure-rated pipe with a different outside diameter (4.500 in for 4 inch). The two do not fit together without an adapter.
Which is stronger, SDR 35 or SDR 26?
SDR 26 has a thicker wall and higher pipe stiffness (115 psi versus 46 psi), so it is used under deep fill or where specified.
Sources
- ASTM D3034, Standard Specification for Type PSM Poly(Vinyl Chloride) (PVC) Sewer Pipe and Fittings, Table 1 Pipe Dimensions
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