FAQ
Hydro excavation
What is the best hydrovac nozzle?
It depends on the ground. Rotating turbo nozzles are the general-purpose choice. Solid-stream nozzles like the Hydra-Flex Switchblade cut hard, packed ground. The Ripsaw HD is coated for frost, shale and rock, and the DigPig Silencer puts a 0° stream into a 10° cone. Match the nozzle size to your pump's flow and pressure.
What do hydrovac nozzle size numbers mean?
They are orifice sizes, not GPM. Flow depends on pressure: a No. 8 nozzle runs about 6.3 GPM at 2,500 PSI. A smaller orifice gives a tighter spray and less water per load; a larger one digs faster but fills the tank with more water.
What nozzle size should I use for clay, sand, rock or frozen ground?
Published guidance: sizes 6 or 8 for calcrete, hardpan, packed gravel and frozen ground; smaller sizes for rock and shale; 6 to 10 for clay (smaller when dry, larger when wet); 9 for loam; 10 or 12 for pit run; 12 for sand, topsoil and loose gravel. Use smaller nozzles on contaminated soil, since disposal is charged by weight.
What water pressure should I use when hydro excavating around utilities?
Ditch Witch recommends 2,500 to 3,000 PSI with a rotating nozzle, reduced when you are using heated water. Keep the nozzle moving so the water never concentrates on one spot.
How close can the nozzle get to a buried utility?
Ditch Witch's guidance is to hold the nozzle 6 to 8 inches from the utility and keep it moving. Never push the nozzle into the dirt to dig; it clogs the nozzle and slows you down.
How hot should the water be for hydro excavation?
Hot water helps in hard clay and frozen ground, but Ditch Witch recommends keeping it below 150°F around utilities and turning the pressure down when the water is heated.
Why use a rotating nozzle instead of a straight stream near utilities?
A rotating (oscillating) nozzle has no fixed direct spray that can cut into a line, and Ditch Witch says it can use up to 50% less water than a fan nozzle.
Why is my hydrovac losing water pressure?
The usual causes are a worn or wrong-size nozzle tip, or an unloader valve that is stuck open or misadjusted, often from sand in the valve seats. Replace the tip or clean the unloader, and set pressure to match the nozzle size.
Why does my water pump hammer or bang with no water flow?
A clogged strainer on the supply side of the triplex plunger pump is the common cause. Shut down, clean the strainer, then open the drain valve on restart to purge air from the supply line.
Why is my vac truck losing suction?
Check the vacuum gauge. High vacuum at idle points to a clogged hose; low vacuum while working points to a tear or hole. Clogs usually form where the hose changes between vertical and horizontal. Dirty filters and cyclone separators also cut suction, so carry spares.
How long does a hydrovac turbo nozzle last?
Nozzles are consumable. One published example puts a low-cost nozzle at a month or two and a premium nozzle at over a year. Brands that sell rebuild kits and individual parts cost less over the nozzle's life.
How far from the truck can a hydrovac dig?
A standard blower works within about 200 feet of the truck. Longer runs or deep holes that need more lift call for a more powerful blower.
How do I change the pills on a Switchblade nozzle?
The tungsten carbide pills thread in and out of the Switchblade body. Remove the old pill, wrap the new one with stainless thread tape and thread it in. Swap pill sizes to match a different pump or soil, or replace worn pills instead of the nozzle.
How much does a DigPig Silencer nozzle cost?
The DigPig Silencer is $550 in every size, #4.0 to #12.0. Refresh kits, seats, O-ring kits and covers are sold separately so you can rebuild it instead of buying a new nozzle.
What size dig tube does my hydrovac need?
Match your truck's suction diameter (6" or 8") and the connection on your boom: flat flange (Vactor and Vac-Con style), Bandlock or Ringlock. HDPE tubes are non-conductive; aluminum tubes come with a non-conductive poly cuff on the digging end.
Sewer jetting
How do I choose a sewer jetting nozzle?
Match it to three things: your jetter's rated flow (GPM) and pressure (PSI), the thread on your hose end, and the pipe diameter. Flow moves debris; pressure does the cutting. A nozzle sized wrong for your machine underperforms no matter how good it is.
Penetrating, flushing or rotating: which sewer nozzle do I need?
Penetrating nozzles put energy forward to open full blockages; follow with a flushing nozzle. Flushing nozzles use wide rear jets for routine cleaning, sand and grit. Rotating nozzles spin their jets to scrub grease and scale but need the right flow and pressure to turn.
Will a water jet cut through tree roots?
Not a heavy root mass. Standard jets won't shear thick roots; you need a mechanical cutter or root saw driven by the jetter, rated for your pipe material.
What size root saw blade do I need?
Root saws are labeled by the pipe size they are made for. Industry guidance is to run a blade slightly smaller than the pipe diameter so it gets through offsets and deflections. Concave blades cause less wear on the pipe wall than flat blades.
Should I clean on the way in or on the way out?
Clean on the way in and rinse on the way out. KEG's training says this clears a line in one pass about 95% of the time. Pulling back fast to "clean on the way out" wastes water and can push sewage into homes.
How fast should I pull the nozzle back?
Read the returns. Heavy debris means slow down so you don't outrun the water carrying it; a clean hose means the line is clean. High-angle, large-orifice nozzles can clean at about 10 to 20 feet per minute.
What causes blown toilets when jetting?
Usually a closed upstream manhole and the way the line is jetted. Open the upstream manhole; a sudden rush of return water is a sign it was closed. KEG's trainer attributes about 95% of blown toilets to operator technique.
What does a sewer nozzle's tier rating mean?
The 1 to 3 tier system rates water flow through the nozzle, not how well it cleans. In KEG's figures, a Tier 1 drilled nozzle is about 30% efficient and Tier 3 nozzles run 75% to 98%.
More jets or fewer, larger jets?
Fewer, larger orifices put more impact force on the pipe wall. More, smaller orifices spread the water but weaken the impact. Higher jet angles also deliver more thrust.
How do I pick a KEG sewer nozzle?
Start with your hose size, then the minimum pipe size for that model. Choose the model by job: Rambo and Drill Point for total blockages, Egg and Sewer Flush for general cleaning, Stallion and Traction for weakened pipe, Royal and Jet Floor Cleaner for heavy debris in big pipe.
What is a wet well cleaning nozzle?
A long-reach 0° nozzle that cleans lift stations, wet wells and manholes from the top. The Hydra-Flex Marksman reaches 20+ feet at 500 to 2,500 PSI.
What does a nozzle extension or skid do?
It threads between the hose and nozzle and holds the nozzle centered and off the pipe floor, which reduces nozzle wear and keeps it from turning up laterals. Southland sizes them by hose size x pipe size, so the size you pick is the pipe diameter, not the length.
What is a leg proofer?
A multi-leg tool pulled through a cleaned line on the jetter hose to confirm it is open and round before inspection or lining. Proofers are made 1/2" under the listed pipe size so they pass a sound line.
What is a manhole roller guide for?
It keeps jetting hose and camera cable off the rough manhole rim and pipe edge so the hose doesn't wear through. Most are sized by manhole opening, 24" or 36".
What does a tiger tail hose guide do?
It sleeves the jetting hose where it bends over the manhole edge and into the pipe, so the hose rides on rubber instead of concrete.
How does a Vac-Trap work?
It clamps to the end of your suction tube and sits in the invert. Debris is picked up while most of the water stays in the sewer, so you don't decant or haul extra water, and the open bottom leaves room to keep jetting.
Filters and cross-reference
What Donaldson filter replaces the Fleetguard LF9009?
The Donaldson DBL7300 Donaldson Blue lube filter. It also replaces Cummins 4906635 and Baldwin B40142. Confirm against your old filter.
What Donaldson filter replaces the Fleetguard FF5825NN?
The Donaldson DBF6776 Donaldson Blue secondary fuel filter, which also crosses to Cummins 5365988 and Baldwin BF46129.
What replaces the Racor S6464 fuel water separator?
The Donaldson P551034 Twist&Drain fuel water separator. It also replaces Fleetguard FS19798 and Baldwin BF1347.
What Donaldson hydraulic filter replaces the Fleetguard HF6553?
The Donaldson P164378 spin-on hydraulic filter, which also crosses to Baldwin BT8851-MPG and several Vermeer, John Deere and Caterpillar numbers.
What Donaldson filter replaces the Fleetguard LF14000NN?
The Donaldson P559000 full-flow lube filter (M95 x 2.5 thread). Donaldson lists the DBL7900 as its Donaldson Blue alternate.
What Donaldson filter replaces the Fleetguard FF63009?
The Donaldson P553009 secondary fuel filter, which also crosses to Fleetguard FF63054NN and Baldwin BF63000.
What Donaldson filter replaces Allison 29540494?
The Donaldson P560971 Allison transmission filter kit. It also crosses to Fleetguard FS20087 and Baldwin PF7986.
What air filter fits a Kenworth T800 or Peterbilt 579?
Donaldson lists the P616056 PowerCore primary air filter for the Kenworth T660 (2008 to 2017), Kenworth T800 and Peterbilt 579 (2013 to 2025). It crosses to Fleetguard AF27688 and Kenworth P611696.
What cabin filter fits a Kenworth T800 or T880?
The Donaldson P646195, which crosses to Fleetguard AF56102, Baldwin PA30269 and WIX WP10417.
What replaces the Detroit Diesel R61709 fuel water separator element?
The Donaldson P552709, rated 99.9% at 10 microns. It also crosses to Fleetguard FS20176.
How do I find the right vac truck final filter?
Match the part number on your old filter, or measure outside diameter, inside diameter and overall length and match all three. The final filter is the last protection before the blower, so a loaded or torn one costs you suction or a blower.
Ordering
Who is HydroVac Supply?
An operator-owned supplier of hydrovac and sewer jetting parts in Blair, Nebraska, founded in 2024 by a hydrovac operator. Call 402-237-1914, Monday to Friday, 7AM to 4PM.
Do you ship outside the United States?
No. HydroVac Supply ships within the US only.