Hydro-Jetting

A cable bores a channel through a blockage. Water runs, the invoice gets paid, and the line backs up two months later because the grease never left the wall. EPA says as much about rodding: the tool "may only loosen the material to be flushed out at a later time." Jetting takes the deposit off the wall instead of drilling past it.

That is the real case for jetting. Now the part that almost never reaches a plumber's website, though it is arithmetic anyone can check.

The pressure has to match your pipe, not the truck

US Jetting publishes a nozzle chart. The half inch nozzle, sized for pipe from 4 to 24 inches, is rated at 3,000 to 6,000 psi and 12 to 18 gpm. Your house lateral is probably 4 inch, at the very bottom of that band, so the setup a crew runs on a county main technically covers it.

Then read what the pipe makers say. An Enz USA nozzle manual warns that with modern thin wall pipe, "do not exceed 1,400 psi of water pressure at the tool." An Insituform guide says a cured-in-place liner should never be mechanically cleaned at all, and jetting it "should never exceed 2,000 psi or damage could occur." Fiberglass maker Amiblu caps jetting near 870 to 1,450 psi.

Why the camera goes in before the hose

EPA settles the sequence. Its guidance calls inspection and evaluation of the current sewer condition necessary before a method is chosen, and its CMOM guide adds that cleaning comes first so the camera has clearance. That pass establishes four things.

• Material. Clay, cast iron, Orangeburg, plastic or a liner. This sets the ceiling.
• Diameter. EPA puts CCTV's range at 4 to 48 inches, so a lateral is in range. A sink branch is not.
• Each defect, by footage from the start. Offset joint at 38 feet means something. "It looked rough" means nothing.
• How clean the line got. EPA's inspection record includes that for a reason.

Your report should name pipe size, material, footage to each defect and how clean the line ran. Keep the video. If material is the open question, start with our pipe materials by decade page and the year the house was built.

What the camera cannot tell you

Anyone saying the camera showed everything is overselling a tool. EPA is blunt: "CCTV, however, cannot capture pipe condition below the water," and the reading is "subjective and can be error prone as its accuracy depends heavily on the skill and concentration of the operator." Standing water hides the bottom of the pipe, which is where sags and cracks live. A look from the cleanout is not an inspection either. EPA puts that at 10 to 12 feet of visible pipe.

Where the water goes when someone gets this wrong

EPA's table of cleaning limitations describes a specific Woodbridge house. Hydraulic methods "are only successful when necessary water pressure or head is maintained without flooding basements or houses at low elevations," and for jetting, "cautions need to be used in areas with basement fixtures and in steep-grade hill areas." On high velocity cleaning: "Backups into residences have been known to occur when this method has been used by inexperienced operators."

Plenty of housing here has a basement bath or laundry, much of it on grade falling toward the Occoquan. The lowest fixture is where water goes when a line will not take what you put in, so we find those first. Worth knowing the rule: where a fixture's flood level rim sits below the lid of the next manhole upstream in the street, code says it belongs behind a backwater valve. Residential code P3008.1, Section 715 in the plumbing code.

Lines we will not jet, and what we say instead

• Suspected Orangeburg. Bituminous fiber pipe deforms after roughly thirty years, and "the flattened pipe can be further damaged by the use of drain-cleaning tools." The Uniform Plumbing Code allowed it from 1955 to 1982, mostly installed 1940 to 1970.
• A lateral already lined. Mechanical cleaning is out and pressure caps at 2,000 psi. If nobody knows whether it was lined, we find out before picking a nozzle.
• An open break or a collapse. Nothing to clean, and high pressure water moves sewage and soil around outside the pipe. That is repair or replacement.
• A belly or sag. EPA's velocity data is why. Below roughly 1.0 to 1.4 ft/sec grit and solids settle out, where 2.0 ft/sec largely scours itself. A sag drops velocity every time water runs, so it reclogs on a schedule however clean we leave it.
• Defects at several joints. We show you the footage marks and talk about full length work instead of booking you every spring.

For everyday clearing, drain cleaning is usually the cheaper right answer. If the camera finds structural trouble, the choice is lining or open replacement, and EPA is clear: replacing a defective line "results in a line segment design life that exceeds any other rehabilitation method." Trenchless is right when digging would be brutal, not because it is better pipe.

Roots: jetting is a clean, not a cure

A peer reviewed review in the ASCE Journal of Infrastructure Systems found roots cause more than half of all stoppages in sewer systems, and Fairfax County cites that same paper. Roots are the base case on older pipe here, not an exotic diagnosis.

The inconvenient half: the same review reports that "roots frequently grow back more vigorously after each cutting operation." Cut them, they come back thicker. An annual root cutting plan is a subscription to the symptom.

Roots do not drill through sound pipe. They follow moisture into a joint that already failed. Pre 1960 joints were rope and mortar with an assumed life of 25 to 30 years, and the paper found far lower intrusion rates in pipe laid after 1970. EPA credits professional in-pipe chemical root control with longer lasting effect than a rodder, roughly two to five years. That is a foaming treatment an operator applies inside the pipe, not copper sulfate crystals down a toilet, which no study tested. Jet it open, treat it where treatment fits, then close the defect. Only the last step ends it.

Kitchens, and the people who manage buildings full of them

In a restaurant, grease is not an event. It is a condition. This is the work jetting was built for, and EPA describes it that way: jetting "removes debris and grease build-up, clears blockages, and cuts roots within small diameter pipes" and suits routine cleaning of small diameter, low flow sewers. Kitchens we look after run on an interval set by the first camera pass, and we work after hours so the dining room never sees a hose.

The cheaper levers, though, are inside the building. Fairfax County's sewer rules prohibit discharging viscous substances such as fats, oils and grease that can block sewers, and cap petroleum oils at 100 parts per million. Across the river, WSSC Water says it has spent $2.5 million on grinders at pumping stations to deal with wipes, and gives the one test worth teaching a crew: does it dissolve like toilet paper? If not, it is not flushable. Fairfax County says the same thing about wipes, including the ones labeled flushable. A dish crew that gets that right buys you months between visits.

• Check the cleanout caps. EPA cites a study finding almost 25 percent of lateral defects were related to missing or damaged cleanout caps. A missing cap lets storm water straight into the lateral, and it is the cheapest fix on any property you own.
• Assume it is your pipe first. In an EPA documented program in Montgomery, Alabama, 85 percent of the problems found across nearly 2.2 million feet inspected were service lateral problems, roughly one defect every 700 feet.
• Old cast iron benefits twice. EPA notes clay and plastic resist hydrogen sulfide corrosion where concrete, steel and iron are more susceptible, and that cleaning out deposited solids reduces sulfide generation. Scheduled cleaning on an old cast iron stack does more than keep the smell down.
• Jetting is the prep step for lining, not an alternative. EPA is flat about it: the lateral must be thoroughly cleaned prior to lining. A lining quote that arrives before the line was cleaned and filmed is a guess.

How often, really

EPA will not name one interval and neither will we. Its guide puts the spread at ten to one: a restaurant district may need cleaning every six months to stay ahead of grease, while sound PVC with good slope "may be able to go five years with no problems." For a house with one bad spring every year, the question is not how often to clean it. It is what sits at the footage where it keeps backing up.

Common Questions