Mastering Wisconsin Plumbing
This podcast is dedicated to making the Wisconsin Plumbing Code (SPS 381–387) more accessible for plumbers, apprentices, inspectors, and designers.
Mastering Wisconsin Plumbing
Circuit Vents, Vertical Wet Vents, and Knowing When to Upsize
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In this episode of Mastering Wisconsin Plumbing, Ryan dives deep into two of the most versatile—but often misunderstood—venting systems in the Wisconsin Plumbing Code: circuit venting and vertical wet venting.
You’ll learn:
- Why circuit venting only works with all wall outlet or all floor outlet fixtures
- When a relief vent is required (hint: 4 or more fixtures)
- How to size vent piping without violating code
- What OTWV stands for (and why it’s worth knowing)
- How vertical wet venting works with pairs like laundry tubs and ACWs
- A real-world trick to reduce pipe sizing just by flipping your fixture layout
Plus, Ryan teases next week’s topic—water pipe sizing theory—which will unpack the pressure, friction, and fixture unit logic behind smart, efficient plumbing systems.
Whether you're in the field or studying for your Master’s license, this episode gives you practical tools to apply SPS 382.31 venting provisions with confidence.
References / Resources Mentioned:
- Wisconsin Administrative Code SPS 382.31 – Venting systems design and sizing
- SPS 382.40 – Fixture unit table for water sizing (previewed for next episode)
- SPS 381.01(288) – Definition of “wet vent”
- Wisconsin DSPS Plumbing Code Home Page – https://dsps.wi.gov/Pages/Programs/Plumbing/Default.aspx
