Bypass Plugs
Cherne Muni-Ball bypass plugs — seal the pipe while diverting flow through a built-in bypass channel. · 19 products
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About Bypass Plugs
Repair Work Without Shutting Down the Line
Active sewer lines don’t stop flowing because you need to make a repair. A bypass plug seals the pipe at the work zone while routing flow through an internal channel to a temporary line downstream. Your crew works in a dry area; the sewer keeps running.
Sizing the Bypass Channel
This is the decision that matters most. The bypass channel diameter determines how much flow can pass through while the plug is set:
- 3/4” bypass — Low-flow residential laterals. Single homes, small-diameter service connections.
- 1” to 1-1/2” bypass — Residential mains and light commercial lines.
- 2” to 3” bypass — Municipal trunk lines, multi-family feeds, and higher-volume applications.
When in doubt, size up. An oversized bypass won’t cause problems, but an undersized one risks sewage backup behind the plug.
Blocking vs. Bypass — Quick Reference
Use a blocking plug when the line can be fully isolated (pressure testing, smoke testing, new construction). Use a bypass plug when flow must continue during the work (repair, replacement, spot lining).
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Frequently asked questions
What is a Muni-Ball bypass plug?
A Muni-Ball is Cherne's pneumatic bypass plug: it inflates to seal the pipe like a blocking plug, but a built-in flow-through channel diverts active flow past the work zone through a hose or temporary line. That lets crews repair, replace, or spot-line an active sewer without shutting off service upstream.
How do you install a sewer bypass plug?
Insert the deflated plug through a manhole or access point upstream of the work zone and connect your bypass line to the flow-through port. Inflate to the rated pressure with a regulated air source; flow then passes through the internal channel and bypass hose while the plug seals the pipe. Deflate fully before removal.
How do I choose the right bypass size?
Match the bypass diameter to your expected flow rate. 3/4” for single residential laterals, 1”–1.5” for residential mains, 2”–3” for municipal trunk lines. Size up if unsure — excess bypass capacity won't hurt, but insufficient capacity causes sewage backup behind the plug while the line is plugged.
Can I use a bypass plug for pressure testing?
No. Bypass plugs have an open channel by design — they can't hold pressure. For pressure testing, use a blocking plug (Test-Ball) that creates a complete seal. The bypass channel is for keeping an active line flowing during repair work, not for isolation testing.
What pipe sizes do Muni-Ball plugs fit?
Our Muni-Ball lineup covers pipe from 4” up to 18”, including multi-size plugs that span ranges like 4”–6”, 8”–10”, and 12”–18” so one plug handles several diameters. Bypass channels run from 3/4” to 3”. Match the plug to your pipe's inside diameter, then size the bypass to your expected flow.
How much does a bypass pipe plug cost?
Our Cherne bypass plugs range from about $170 for small single-size Muni-Balls to roughly $2,575 for large multi-size plugs covering 12”–18” pipe. Price scales with pipe diameter and bypass channel size. For recurring or volume orders, call (866) 514-3684 for contractor pricing.