Sewer Jetting Efficiency: Why It Pays to Jet Upstream When You Can

You're on a service call. Your camera's already down the line and the screen shows exactly what you expected: completely blocked main, sewage backed up to the cleanout, potentially a real mess to jet. Your instinct says pull the camera from the cleanout and start jetting from there as it’s the handiest access, closest to the stoppage. That’s the default move on most calls, right? But what if there's a smarter access point outside the building where you could attack the dry side of the blockage? Running your jetting hose and nozzle upstream toward the clog could make the job far easier … and much less messy.

Sewer jetting isn't just about choosing a nozzle and letting it fly. Which direction you enter the line to jet matters just as much to your efficiency as which nozzle you grab. When you can access the line from a downstream access and jet upstream toward the blockage, you'll typically clear it faster and cleaner than jetting downstream – every time. Here's when that switch makes sense, and why it works.

What Does "Jetting Upstream" Actually Mean?

Before you change your approach on the next call, it helps to get the terms straight.

Downstream jetting means running your hose from an access point in the building, like a cleanout closest to the backup, and then blasting away at the clog in hopes of blowing it downstream toward the street. Seems logical enough, but upstream jetting flips that; you access the line from a point closer to the street and jet back toward the building instead.

Why Jetting Toward the Building Can Be More Efficient

This isn't about completely ditching downstream jetting – often that’s the only option if there’s no outside access. This is about taking a moment to look for an outside access to jet toward the building, because if there is, your jetting will be more impactful and efficient – which equals less time on the job. Here's why flipping the direction to jet “upstream” is often worth it.

Allows the Nozzle to Attack the “Dry Side” of the Blockage

Jetting upstream toward the building from an outside access lets your nozzle hit the “dry side” of the blockage first, allowing its waterjets to attack the blockage without being diluted and muffled by the standing water of the backed up line. This approach allows your nozzle's water-jets to impact and clear the blockage with maximum efficiency.  By contrast, when you jet downstream into a backed up line you're forcing your nozzle’s waterjets to fight through the standing water and debris to hit the blockage. That’s like expecting a boxer to fight while in a swimming pool – their punches would be hindered by the water and have significantly less impact as they would in the boxing ring.

Enables the Nozzle to Pull Back Debris In the Natural Direction of Flow

Sewer and drains systems are designed to flow toward the street, and jetting nozzles are generally designed to pull debris back toward them in a “back flushing” mode – that’s why nozzles typically have more “rear” jets than “front” jets (and why they thrust themselves into the line). When jetting upstream toward the building your nozzle will be naturally pulling debris away from the building's fixtures instead of blasting it all back toward them. Obviously that matters most on a backed-up line, where the last thing your customer wants is for sewage and debris to be regurgitating into their clean spaces. By contrast, jetting upstream enables efficient flushing-action as you pull the hose/nozzle back toward the point of entry.

Efficient and Safe Flushing of Scale from the Line

Do you often need to flush scale from the pipe after you’ve de-scaled it with a flex-shaft or milling machine? Jetting from a street-side access allows the nozzle to “pull” the scale from the line toward the street with a nozzle’s typical back-flushing action. This mode is radically more time-efficient than asking the nozzle to “push” the debris toward the street, and is definitely MUCH safer than using an “all-forward” type of jetting nozzle that wants to blow itself out of the pipe under pressure, potentially causing a serious water-jet injury.

Where Upstream Jetting Shines: Grease-Packed and Root-Infested Lines

Some jobs benefit from this more than others.

Grease-packed mains are often an opportunity for upstream jetting to earn its keep. Look for jetting-access at the grease trap or interceptor and attack the blockage from the dry side. Once flow is re-established, then you can efficiently scour out all the remaining grease-buildup and pull it all back to the trap or interceptor. 

Similarly, root-infested lines can be a bigger job than just clearing a blockage, as roots can grow in from every joint and crack, requiring a good camera view to direct efficient jetting work of each point of infiltration. Many of you use Reaper or Warthog nozzles to clear tough blockages; try pairing that combo with an upstream-jetting strategy on your next root-packed main and see how much faster the line opens up. The same holds true for other blockages and buildup you'll run into on a service call. See our full nozzle breakdown for more on how each of these nozzles earns its place in the truck.

When Downstream Jetting Still Makes Sense

Plenty of jobs don't give you a choice. If there's no access outside of the building, jetting downstream is your only choice.

And if the line is not severely backed up, downstream jetting might allow for faster setup for a quick blast out of a soft clog or mild blockage. The point isn't that one direction beats the other every time. It's that you've got two directions to work with, and picking the right one for the job in front of you is part of doing the work efficiently.

Access Point Considerations Before You Choose a Direction

A few things to check before you commit to a direction:

• Locate a cleanout, interceptor, or other access point near the street, downstream of the blockage

• If none are near the street, check for access points closer to the building, still downstream of the problem area

• Do a camera inspection of the line to confirm the severity of the blockage, and its location relative to potentially handier indoor access. If the blockage looks light and is close to an indoor access, it might be quicker to jet from inside the building toward the street.  

PRO TIP: Run the camera before you run the hose. Confirming the blockage severity and location up front saves you from picking the wrong access point and doubling your time on the job.

Get Equipped for the Job, Whichever Direction It Takes

Direction is a tool in itself. The next time you're staring down a backed-up line, don't default to the nearest cleanout out of habit. Run the camera, check your access points, and jet from whichever side that’ll be the most efficient, clean, and safe for that particular jetting job. 

Need help building out your jetting setup for jobs like this? Shop our root-clearing nozzles to handle root-packed lines from either direction. Check out more technique breakdowns on our YouTube channel, or give us a call if you want to talk through your setup.

Want to see jetting tips, training, and nozzles action? Check out our “Get” Jetting video library for a wealth of jetting information..

Get equipped and get jetting.

JETTERS NORTHWEST is a 20+ year-old product line of Seattle Pump & Equipment Co., a service and sales center for jetters for over 50 years.

Frequently Asked Questions

Q: What's the difference between jetting upstream and downstream?

Downstream jetting typically runs from an access point inside the building and requires “pushing” debris away from the building, toward the street. Upstream jetting runs from an access point closer to the street and “pulls” debris away from the building back toward the street in its natural direction of flow. The access point you start from also determines whether your nozzle will be attacking a total blockage from the “dry” side or the “flooded” side. 

Q: Does jetting direction matter for tree root removal?

Root-packed mains often clear faster when you jet upstream, working from the street-side into the dry side of the blockage instead of pushing through standing water to reach the root mass from the building side. Combining the right nozzles with the right access point makes the biggest difference in clearing tough root jobs efficiently.

Q: Can I always choose which direction to jet a sewer line?

No. Your access points determine your options. If there's no jetting access outside the building, you'll have to jet downstream from an indoor cleanout or you’ll have to pull a toilet for access. Upstream jetting only works when a usable access point exists downstream of the blockade or buildup, allowing you to run the nozzle and hose upstream into the problem area that needs cleared.

Q: Should I do a video inspection before deciding jetting direction?

Yes, why not? A quick camera run shows you exactly where the blockage sits, its severity, and which access point might give you the better approach before you commit.