What is Bypass Pumping and When Do You Need It?

What is Bypass Pumping and When Do You Need It?

If you work in municipal infrastructure, utility contracting, or heavy civil construction, you've probably heard the term bypass pumping. But what exactly is it, when do you need it, and what equipment does it require?

Here's everything you need to know.

What is Bypass Pumping?

Bypass pumping is the process of temporarily rerouting the flow of a pipeline — typically a sewer main, water main, or stormwater line — around a section that needs to be repaired, replaced, or inspected.

Instead of shutting down the line completely and stopping all flow, bypass pumping keeps everything moving while the work gets done. The pump picks up the flow upstream of the work zone, moves it around the repair area through temporary above-ground piping, and discharges it back into the line downstream.

When Do You Need Bypass Pumping?

Bypass pumping is required any time you need to work on a live pipeline without interrupting flow. Common situations include:

• Sewer main repairs and replacements — the most common application. Sewage flow must be maintained continuously to prevent backups and public health issues
• Pipe lining and rehabilitation — cured-in-place pipe lining requires a dry pipe which means all flow must be bypassed during the curing process
• Manholes and junction repairs — any work that requires dewatering a section of active sewer line
• Emergency pipeline failures — when a main breaks unexpectedly, bypass pumping maintains flow while emergency repairs are made
• Water main work — bypassing sections of water distribution lines during repairs or valve replacements
• Stormwater infrastructure — bypassing culverts, detention basins, or stormwater lines during maintenance or replacement

What Equipment is Used for Bypass Pumping?

The equipment required depends on the size of the pipeline and the volume of flow that needs to be bypassed.

Submersible pumps are the most common choice for bypass pumping applications. They sit directly in the upstream manhole or wet well, handle the incoming flow continuously, and push it through the bypass line. They're built for the continuous operation that bypass pumping demands.

High volume diesel pumps are used for larger diameter mains where flow volumes are significant. These are surface mounted pumps that can handle thousands of GPM for extended periods.

Bypass piping and hoses connect the pump to the discharge point downstream. Sizing the bypass line correctly is critical — undersized piping creates back pressure that reduces pump performance.

Key Considerations for Bypass Pumping

Flow rate — you need to know the peak flow rate of the pipeline you're bypassing. Your pump must handle peak flow, not just average flow. Undersizing the pump is the most common and most costly mistake in bypass pumping.

Redundancy — for critical infrastructure like active sewer mains, always have a backup pump on standby. If the primary pump fails during a bypass operation the consequences are immediate and serious.

Setup time — bypass pumping setups need to be operational before any work begins on the live pipe. Plan for setup time in your project schedule.

Duration — how long does the bypass need to run? Short term bypass operations and long term rehabilitation projects have different equipment requirements. Fuel consumption, maintenance access, and reliability all factor in for extended operations.

Discharge location — where does the bypassed flow go? The downstream discharge point needs to be carefully selected to avoid backups or environmental issues.

Bypass Pumping for Municipalities vs Contractors

Municipalities running bypass pumping operations on public sewer systems typically have strict requirements around pump redundancy, monitoring, and environmental compliance. Equipment must be reliable and operators must be available around the clock for extended bypass operations.

Contractors performing bypass pumping as part of a rehabilitation or repair project need equipment that deploys fast, runs reliably for the duration of the job, and can be demobilized quickly when the work is complete.

In both cases the priority is the same — keep the flow moving without interruption.

How Flowcor Equipment Supports Bypass Pumping Projects

At Flowcor Equipment we supply submersible pumps, high volume diesel pumps, and bypass pumping equipment to contractors and municipalities across the U.S. We work on a quote basis — you tell us the pipeline size, flow rate, and project duration and we source the right equipment and ship directly to your job site.

Submit a quote request and we'll get back to you within 1 business hour with equipment recommendations, pricing, and lead times.