Understanding Pulsation in Sewer Jetting: What It Is—and What It Isn’t

When it comes to high-pressure sewer jetting, performance isn’t just about raw Pressure (PSI) or Gallons Per Minute (GPM) capability.  A key—but often misunderstood—feature is Pulsation, also known as “hose jump.” In this blog, I’ll break down what pulsation is really designed to do, when to use it, and common mistakes that can reduce jetting performance by over-using pulsation.

What Pulsation Is:

Pulsation is a feature that causes the jetting hose and nozzle to vibrate or “jump” inside the pipe while jetting. This vibration reduces friction between the jetting hose and the inner walls of the pipe to reduce or even eliminate “hose-drag” in the pipe. 

This is especially useful when:

• Advancing the hose & nozzle up longer pipelines

• Navigating the hose & nozzle through tight bends or multiple elbows in the pipeline

Consider this motto: “If you can’t get to it (the blockage) then you can’t get through it!” Pulsation simply helps the hose and nozzle move more freely in the pipe to help reach the areas to be cleaned. 

The primary purpose for Pulsation that has bailed me out a few times while jetting:

• Pulsation can free up a stuck nozzle during hose-retraction!

I’ll never forget doing a new-jetter training 20-some years ago for a group of plumbers at a school. We ran the hose & nozzle about 130 feet into a 4” cast iron sewer, under the slab of the building, from an outdoor cleanout. When pulling back the hose, the nozzle got stuck about halfway back; so stuck that the torque of the jetter’s motorized hose-reel was pulling the tail of its trailer several inches down toward the ground. That nozzle was stuck. But it would go forward, so I tried sending the nozzle forward and pulling back several times–no luck. I tried increasing and decreasing the throttle and the pressure before rewinding–no luck. Every time it got stuck in the same spot. It was late Friday afternoon. The crew were all on overtime. What to do? 

Then I realized that the jetter included a Pulsation system, so I sent the nozzle forward into the pipe about 15 feet, lowered the engine throttle, turned on the pulsation and started rewinding the hose; the nozzle came right on out of the pipe without hanging up. What a relief! I told myself at that moment that every jetter I build from here on out will include a pulsation system whether the customer asks for it or not.

However, pulsation does not enhance cleaning power for attacking blockages; in fact, it typically reduces jetting power significantly...

What Pulsation Is NOT:

Pulsation Does NOT Increase Jetting Power – it actually reduces it! Despite marketing claims from some manufacturers, pulsation does not increase cleaning power. It does not turn your nozzle into a “hammer” inside the pipe to pound on blockages.  In fact, activating pulsation typically reduces jetter pressure and flow at the cleaning nozzle by about 30%! This tradeoff is crucial. Your jetter’s performance relies heavily on optimal water-jet pressure and flow (PSI & GPM) out the nozzle to clear blockages and scour lines efficiently. Yes, pulsation can help get your hose/nozzle up the line to be cleaned, but unnecessary use of pulsation can significantly reduce your jetter’s GPM & PSI performance – handicapping the nozzle's ability to attack blockages and clear the pipe.

Real-World Example of Misused Pulsation causing Huge Drop in Jetter Performance

Several years ago, an operator shared with me that his jetter – though rated for 3000-PSI – had never exceeded 2000-PSI, even back when it was new.  After a brief consultation, I learned he’d been incorrectly trained to run pulsation at all times when jetting. The result? He’d unknowingly been running at reduced GPM/PSI capacity for years simply by operating the jetter incorrectly! So, after explaining what pulsation was really for, I suggested he turn the pulsation off during regular operation, and the jetter immediately hopped up to full 3000psi pressure with significantly better cleaning performance—without need for any new parts or service. The operator was obviously pleased, and we’d won a new customer, as his company later purchased their 2nd jetter from us, and is now looking at adding a 3rd.

Best Practices for Using Pulsation Effectively

• Use pulsation sparingly – Activate only when the hose & nozzle is struggling through tough turns or a long line – and certainly if the nozzle gets stuck in the pipe.

• Turn it off during normal cleaning – to maximize pressure and flow for cleaning power.

• Adjust up as needed; don’t just max out. If your machine supports it, tune the pulsation up just enough to keep the hose/nozzle moving.

Adjustable vs. Fixed Pulsation

Jetters Northwest units include Adjustable Pulsation Systems, allowing operators to fine-tune vibration levels depending on the need of the job:

• Low Pulsation reduces hose-drag with minimal reduction of PSI/GPM power, and minimal machine-vibration.

• High Pulsation is best for shaking a stuck hose/nozzle free—but should be used only as needed due to (a) the significant PSI/GPM loss that happens when the pulsation is at maximum, and (b) the extra machine-vibration that happens when pulsation is wide-open.

Other brands with simple on/off pulsation systems don’t offer this flexibility. They default to high pulsation when activated regardless of actual need of the job, resulting typically in a 25-35% reduction in nozzle pressure & flow when pulsation is on.

Adding Pulsation to Existing Jetters

If your current machine lacks the Pulsation feature, Jetters Northwest or one of its Service Partners can typically retrofit this feature into the jetter.  Adding adjustable pulsation can enhance field performance and operator efficiency without sacrificing significant cleaning power.

Summarizing Pulsation Benefits

Pulsation can help get the jetter’s nozzle to the clog that needs to be cleared, but it’s not a magic wand to make clogs and buildup disappear.  Used correctly, pulsation can maximize the reach of your jetter’s hose/nozzle and—more importantly—can often prevent a job from being delayed by a stalled hose or stuck nozzle.  Used incorrectly, pulsation can and will reduce jetting performance, costing you time and money.

Get Equipped, Get Jetting

Want help evaluating your current jetting capabilities, or getting pulsation added to your equipment? Give us a call, or visit our online store to see what fits your rig. We'll help you find the tailored solution, so you can get equipped and get jetting.