How to buy a used hydrovac or vacuum truck

Buyers get this wrong in one specific direction: they buy a hydrovac when the work is liquid haulage, then discover they are carrying a water tank, a boiler and a boom they never use, on a chassis rated for weight they are not hauling. Start from the job.

Debris tank capacity (cubic yards)

How much spoil the truck holds before it has to drive to a dump site. Around 12 cubic yards is the common utility and daylighting spec; 8–10 suits urban work with a close dump; 15 and up pays for itself on pipeline jobs where the nearest disposal is an hour away. Ask for the usable capacity, not the shell volume — they differ once you account for the deflector and the screen.

Fresh water capacity (US gallons)

How long the crew digs before refilling. 1,300 gallons paired with a 12 cubic yard debris tank is the standard balance; going bigger on water without going bigger on debris just means you fill the debris tank first. Check whether the quoted figure is the total or the usable volume above the pump pickup.

Blower airflow (CFM) and vacuum (in Hg)

Airflow moves material along the hose; vacuum lifts it. A positive displacement blower in the 3,600–5,000 CFM range at up to 27 in Hg is the standard hydrovac setup, and it is what you want for deep digs and long hose runs. Fan systems move more air at much lower vacuum (typically 16–18 in Hg) and are common on combination sewer trucks, where volume of light debris matters more than lift.

Water pump flow (GPM) and pressure (PSI)

Hydrovac excavation pumps typically run 10–20 GPM at 2,000–3,000 PSI — enough to cut soil without damaging a buried line. Combination sewer jetters are a different animal: 60–80 GPM at 2,000–2,500 PSI, because the job is scouring a pipe wall rather than cutting a hole. A pump quoted at high PSI and low GPM will disappoint on clay.

Boom reach, rotation and hose diameter

Boom reach of 20–27 feet with 270–335 degrees of rotation covers most work from a single truck setup. An 8-inch hose is standard; 6-inch is easier to handle but chokes on cobble. Reach matters more than it sounds: every foot the boom cannot reach is a truck reposition, and repositioning in traffic is where the day disappears.

Chassis rating, axles and GVWR

A tandem (6x4) chassis carries most 10–12 cubic yard units; larger debris tanks push you to a tri-drive (8x6) to stay legal when the tank is full. GVWR of 66,000–80,000 lb is typical. Weight law is the real constraint here, especially in Canada — a truck that is legal loaded in one province may not be in the next.

Cold-weather package

A boiler or heat exchanger (commonly 300,000–500,000 BTU), heated cabinets, insulated water tank and full drain-down capability. North of the frost line this is not an option, it is the difference between working in February and parking. A unit sold without it in a cold market is priced accordingly, and retrofitting costs far more than paying for it up front.

A hydrovac spends most of its life stationary with the auxiliary engine at working RPM. That is why a unit can show 120,000 easy highway miles and 9,000 hard pump hours: the odometer describes the commute, not the work. One hour at load is worth roughly 30–50 highway miles of wear, so a truck with 8,000 auxiliary hours has done somewhere between 240,000 and 400,000 miles of equivalent duty on everything downstream of the PTO.

The practical rule: a documented rebuild beats a low reading. A 7,000-hour truck with invoices for a blower rebuild at 6,200 hours and a pump overhaul at 5,000 is a better buy than a 4,000-hour truck whose owner cannot say who serviced it. Hour meters can be replaced and are not tamper-evident in the way an odometer is — always cross-check the reading against service records, tire and hose condition, and wear on the controls the operator touches every day.

• Ask for both numbers in writing before you travel, and ask which engine each figure refers to.
• Photograph the hour meter and the odometer at inspection; compare them to what the advert claimed.
• On a chassis, a 2010-or-later engine matters for emissions compliance in several jurisdictions — see the compliance section below.
• On a trailer unit there is no chassis clock at all, so the auxiliary hours and the tank condition are the whole story.

The honest way to price a specific machine is to compare it against what is on the market this week, not against a published average. Filter live listings to the same type, a similar year and a similar hour band, and read the three closest comparables end to end — including what they disclose and what they quietly leave out.

Brands overlap less than the spec sheets suggest. A municipal combination truck and a hydro excavator share a blower and a debris tank and almost nothing else, and the companies that are genuinely good at one are often not the ones you want for the other. Read the group first, then the brand, then the specific unit.

Corporate ownership matters here for exactly one reason: parts. Federal Signal, Alamo Group and Toro between them own a good share of the names below, and a brand that joined a large group usually ends up with a wider service network than it had alone. It rarely changes the machine you are inspecting.

Use the table as arithmetic rather than as trivia. If a truck is $40,000 under the market for its year and hours, and the blower has no rebuild history at 9,000 hours, the discount is not a bargain — it is the repair, priced in, with the risk transferred to you. Conversely, a seller who can show a $16,000 blower invoice from last season has a genuine claim on a premium, and you should pay it.

1. What are the chassis miles and the auxiliary engine hours today, and which engine does each figure refer to?
2. When was the blower last rebuilt or exchanged, at how many hours, by whom, and can I see the invoice?
3. When was the water pump last serviced, and has the unit ever suffered freeze damage?
4. What is the current tank certification status, and when were the last external, internal and pressure tests?
5. When did it last pass its annual DOT or CVIP inspection, and can I see the report?
6. Is the title clean, is it in the seller’s name, and are there liens registered against the unit?
7. What work has the truck been doing — utility potholing, pipeline, industrial, sewer — and how many hours a week?
8. Why is it being sold, and is it being replaced with the same brand? A fleet replacing like with like is a good sign.
9. Is the cold-weather package complete and working, and was the unit drained every winter?
10. Can you send a video of it digging, showing the vacuum gauge and the water pressure gauge while material is moving?
11. What is included — hoses, wands, tools, spare parts, remote — and what is being kept back?
12. What is the lowest number that buys it today, subject to inspection?

A middle path is worth naming: a low-hour unit two to four years old, bought from a fleet that runs a fixed replacement cycle. It has taken the depreciation hit, it has a full service history because the fleet needed one, and it is usually still inside the window where major components are original and healthy. That is where most of the good buying in this market happens.

• Expect lenders to cap the age of used collateral, commonly around 10 years, and to ask for an appraisal on high-hour units.
• Titled chassis-mounted equipment finances more easily than a trailer or skid unit, because the lender can perfect a lien against the title.
• A lease with a fair-market-value buyout lowers the monthly payment; a $1 buyout is a purchase in all but name and prices accordingly.
• Get pre-approved before you inspect. A seller with two interested buyers takes the one who is funded, not the one who is hopeful.
• Budget insurance before you commit — vacuum equipment carries both auto liability and inland marine or equipment cover, and premiums surprise first-time buyers.
• If you are trading a unit in, get a separate written number for the trade so it cannot be used to blur the price of the machine you are buying.

• Confirm the unit is plated, insured and legal to drive before assuming you can drive it. An expired inspection can strand it at a scale.
• Empty the debris and water tanks before moving. Buyers have been caught paying to transport several tons of someone else’s spoil.
• Oversize or overweight configurations need state or provincial permits, and permit routing can add days as well as dollars.
• For a long haul, price both options: a hired driver for a drive-away is often cheaper than a lowboy for a running truck.
• Inspect at pickup and photograph everything. Damage that appears in transit is far easier to argue with dated photographs.

Title, VIN and lien status

Confirm the title is in the seller’s legal name, that the VIN on the title matches the plate on the chassis, and that the unit was never branded salvage or rebuilt. Run a UCC search in the US or a PPSA search in Canada against both the seller and the VIN.

Annual vehicle inspection

Commercial vehicles need a current annual inspection — the FMCSA annual inspection in the United States, a CVIP inspection in most of Canada. Ask for the most recent report, not just the sticker, and read what was written up.

Cargo tank certification

A tank that hauls regulated liquid — a DOT 407 or 412 code tank on an industrial vacuum truck, for example — carries a certification regime of external visual, internal visual, pressure and leakage tests on set intervals. A hydrovac debris tank is generally not a code cargo tank, but do not assume: check the data plate and ask what the unit is permitted to carry.

Engine emissions compliance

Engine model year governs where a truck may operate. California’s Truck and Bus regulation, in particular, requires 2010-or-newer engine emissions equivalence for most heavy trucks operating in the state, and other jurisdictions have their own rules. Confirm the engine year against where the truck will actually work before you buy.

Registration, plating and operating authority

Weight rating, axle configuration and intended use all affect registration. If the truck will cross state or provincial lines commercially, factor in IRP plating and IFTA fuel tax reporting.

Waste handling permits

What the truck may collect and where it may dump is regulated separately from the truck itself. Confirm the disposal route for the material you will actually be hauling before the machine arrives, because a truck with nowhere to dump is a parked truck.

1. Agree a price in writing, explicitly subject to inspection and to a clear title search.
2. Complete the inspection — ideally an independent one — and renegotiate on what it found rather than walking away over a fixable item.
3. Confirm the seller is who they say they are. Check the business registration, the address and how long the phone number has existed.
4. Run the lien search against the VIN or serial and the seller’s legal name, and get written confirmation that any existing lien will be discharged at closing.
5. Use a written bill of sale naming the parties, the VIN or serial, hours and mileage at sale, exactly what is included, and the as-is or warranty terms.
6. Verify wire details by telephone, on a number you obtained independently — never a number or an account change sent by email.
7. Pay a deposit only against a signed agreement, and consider escrow or a bank draft handed over at collection for the balance.
8. Collect the title, inspection report, tank certification, service records and any manuals at the same time you collect the machine.