Wheel & dust control
Wheel and tire wash systems, and the track-out rule behind them
The federal permit does not name a tire wash. It requires that traffic leaves through designated, stabilized exit points and that sediment does not end up off site — and the EPA's own guidance is unusually candid about which controls actually achieve that. Here is the requirement, the numbers behind it, and what it means for the specification.
Deployed and commissioned — no foundations, no cure time
Wash water recycled in a closed loop, every cycle
Vehicles per hour through a single 4 m bay
Splash guards above the drive surface — the highest in the industry
One machine, four names
A tire wash system — wheel wash, wheel washing system, tire wash station, they are the same thing — is a drive-through bay at the point vehicles leave a site. High-pressure jets clear the tread, the sidewalls and the undercarriage while the wheel is still turning, and the water falls into a tank below that settles the solids out and sends the water back round. Nothing stops, nobody holds a hose, and the vehicle reaches the road clean.
It is not the same thing as a rumble grid or a shaker rack, and the difference is measurable rather than a matter of opinion. The US Environmental Protection Agency's own guidance puts sediment removal at less than 30% up to 60% for gravel pads and shaker racks, against 75% or more for a properly installed wheel washing rack. Where a grid is adequate, fit a grid. Where the road outside your gate is somebody's street, it usually is not — and no dry control reaches the undercarriage at all.
What follows is the regulatory half of the question rather than the equipment half. The equipment — portable decks, concrete pits, bay lengths, tank sizes and dirt traps — is on the wheel and tire wash range pages, linked throughout. This page is about what you have to achieve before you choose between them.
The obligation
No rulebook tells you to buy a wheel wash
What the rules set is an outcome: sediment, mud and slurry must not be tracked onto the public road, and site water must not reach a drain or a watercourse untreated. A wheel wash is one of several controls that can deliver it — a stabilised stone access, a rumble grid, a road-sweeping contract and a wash bay are all on the menu, and which of them is adequate depends on your traffic, your material and the weather.
So the honest answer to "is a tire wash system mandatory?" is: almost nowhere by name. What is mandatory is the result, and a plan that names the control you are relying on to get it. The one place that changes is your own paperwork — a consent condition or a licence that names a wheel wash is not a recommendation.
Where the obligation comes from
The instruments that put a wheel wash on a site plan
Wherever you operate, the duty arrives through some combination of these. Which one bites first decides who you are answering to — and how much notice you get.
| Where it comes from | What it requires | Who enforces it |
|---|---|---|
| NPDES Construction General Permit | Restrict vehicles to designated exit points and stabilize every point that exits onto a paved road — aggregate stone over geotextile, or an equivalent. A stabilized construction entrance/exit is, in EPA's words, "generally a requirement of any construction permit". | EPA, or your state as the delegated permitting authority |
| Your SWPPP | The plan names the track-out control, where it is, who inspects it and how often. The plan is the document an inspector reads first, and a control that is not in it is not a defence. | EPA / state, on inspection |
| EPA's own effectiveness numbers | "Sediment removal rates can range from less than 30 percent up to 60 percent for gravel pads and shaker racks. Wheel washing racks, when properly installed, can remove 75 percent or more of sediment." This is the federal regulator's guidance, not a vendor claim — and it is the argument for a wash rather than a grid. | — |
| State and local stormwater ordinances | Municipal programs commonly go further than the CGP: same-day removal of tracked sediment from the street, street-sweeping requirements, and specified pad lengths. These are the rules that generate the notice. | The municipality or county |
| Design detail, where a stone pad is used | EPA's guidance: stone or gravel at least 6 inches deep for the full length and width of the entrance; shaker racks wide enough for the widest vehicle, long enough to shake, with at least 4 inches of storage beneath. | — |
This is general information about how the obligation is usually framed, not legal advice. The documents that bind you are your own conditions of consent, your licence and your contract — read those first, and where one of them names a control, fit that control.
On the day
What an inspector actually looks at
The road outside, not the bay
The test gets applied on the carriageway. Visible mud, or a sediment plume in the gutter after rain, is the evidence; the state of your equipment is only the explanation. This is why a control that works at 9 a.m. and is overwhelmed at shift change still fails.
One way out, and everybody using it
A control only works if traffic is physically forced through it. Sites with a second, informal exit — a contractor gate, a delivery entrance, a gap in the fence line — fail on the second exit, and EPA guidance says as much in as many words.
Where the wash water goes
A wash bay draining to the stormwater system has swapped a tracking problem for a discharge problem, and the discharge offence is usually the more serious of the two. Containment under the bay, settling, and recirculation is what an inspector expects to see instead.
The paperwork behind it
The plan that names the control, evidence it was running on the day, and the sludge disposal record. Several jurisdictions ask for a wheel-wash log specifically. A control you cannot evidence is, for audit purposes, a control you do not have.
The specification
From obligation to specification
Each line of the duty lands on a specific decision about the machine. This is the translation — and it is also the list of things worth putting to any supplier, ours or anyone else's.
| What the rule asks for | What that means in equipment terms | What sets it |
|---|---|---|
| No visible sediment on the public road | Enough bay length that the tread turns at least once while it is under spray — and more than once where the material is sticky | Bay length. 4 m turns the tread once, 8 m twice, 12 m three times. You are buying rotations, not metres |
| No untreated discharge to a drain or watercourse | A closed loop: containment under the bay, multi-stage settling, oil skimming and coagulant dosing, then recirculation instead of release | Tank capacity — set by throughput and by how long your material takes to settle, which can push it up a size on its own |
| Dust controlled at the exit, not only on the haul road | Wheels, sidewalls and underside wetted and cleaned rather than merely damped | Nozzle layout and pressure: tread, sidewall and under-chassis banks, each aimed rather than sprayed |
| No spray or runoff onto the road or the crew | Splash guards tall enough to keep the wash inside the bay | 2.1 m above the drive surface — the highest in the industry, and measured from the surface the truck drives on |
| Controls maintained in working order for the life of the site | Settled solids removed on a schedule, or removed continuously | A plain settling tank someone empties, or a PCET scraper-conveyor trap that clears itself into a chute |
| A record you can produce on request | Cycle counting, and a maintenance and sludge log | The control system, plus the site's own records — worth agreeing who keeps it before commissioning |
The two ranges
Portable deck, or concrete pit?
A regulator does not care which one you install, only that the outcome holds for as long as the site does. The choice comes down to how long the gate will be there and how much civil work is on the table.
Portable is the answer for a site with an end date: no excavation, commissioned inside a workday, relocated across phases and onto the next project — and it can be hired rather than bought. Concrete earns its civil works where the gate outlives the programme.
- Portable · A bolt-together galvanised deck with drive-on ramps, splash guards and its own tank, standing on a level hardstand. Construction access roads, advancing mines, anything with a programme.
- Concrete · Wash and settling stages built into the ground at the exit, flush with the road. Quarries, batching plants, depots, landfills and long-life mines.
- Both ranges share the same throughput bands, bay lengths, tank capacities and PCET dirt traps, so the specification above reads across either way.
Next
Where to take this
Wheel and tire wash equipment
The main range page: portable deck against concrete pit, the four questions that set a configuration, and how we size either one.
Wheel wash for construction sites
Four questions about your site exit and you have a configuration you can take to a supplier — bay length, tank, water treatment.
Mining vehicle wash equipment
Where the same obligation arrives through a mining lease instead of a planning consent, and the vehicles are haul trucks.
Questions
Common questions about tire wash systems
Is a tire wash system required on a US construction site?
A track-out control is. The NPDES Construction General Permit requires vehicles to leave through designated exit points and those points to be stabilized where they meet a paved road, and EPA's guidance describes a stabilized construction entrance/exit as generally a requirement of any construction permit. Which control you use is yours to choose — and EPA's own figures are the reason many sites choose a wash: less than 30% to 60% sediment removal for gravel pads and shaker racks, against 75% or more for a properly installed wheel washing rack. Check your state permit and the local ordinance, which frequently add same-day street cleaning.
What is the penalty for tracking mud onto a public road?
It depends which duty is breached, and there are usually three available at once: a road or highway offence for depositing material on a carriageway, a water-pollution offence if the runoff reaches a drain, and a breach of the conditions your site was approved under. In practice the first contact is a notice and the cost of cleaning the road — often recoverable from you by the road authority — and the expensive outcome is a stop-work order on a programme rather than the fine itself.
Rumble strips, shaker rack or wheel wash?
They sit at the same point on the site and do the same job with different effectiveness. EPA puts gravel pads and shaker racks at less than 30% to 60% sediment removal and a properly installed wheel washing rack at 75% or more. EPA also makes two operational points that decide it in practice: a control only works when site rules force all traffic through it, and a shaker rack needs enough storage beneath it — about 4 inches — or it stops working as it fills. A wash also reaches the undercarriage, which nothing dry does.
How long does a tire wash cycle take, and will it queue the gate?
A single pass, without stopping, in under a minute — the vehicle drives through at a crawl and the jets run while the wheel turns. A 4 m bay clears around 50 vehicles an hour, which is why the sizing question is peak hour, not daily average: the queue that matters is the one at shift change. Bay length is the lever, because it is also how many times the tread turns under spray — 4 m turns it once, 8 m twice, 12 m three times.
How much water does a tire wash system use?
Far less than hosing by hand, because the water is recirculated rather than consumed. Up to 90% of the wash water is recovered every cycle: it drops into a tank below the bay, the solids settle out in stages, an oil skimmer and coagulant dosing clean it up, and it goes round again. The system draws make-up water to replace what leaves on the vehicle and in the sludge. Containment is also what keeps the discharge question out of scope — nothing goes to the drain.
What records will an inspector ask for?
The plan that names the control, evidence that it was working on the day, and the sludge disposal record. Several jurisdictions ask for a wheel-wash log specifically, and dust-control regimes that inspect against a checklist treat "was it running" as a separate question from "do you have one". A control you cannot evidence is, for audit purposes, a control you do not have.
Portable or concrete, for a site that has to satisfy a regulator?
The regulator does not care which, only that the outcome holds for as long as the site does. Portable wins where the exit moves: no excavation, commissioned inside a workday, relocated across phases and onto the next project — and it can be hired rather than bought. Concrete earns its civil works where the gate outlives the programme: a quarry, a batching plant, a depot, a landfill or a long-life mine.
What happens to the mud the system collects?
It settles out of the water in the tank under the bay and leaves as sludge. With a plain settling tank that is a scheduled job, usually done by plant already on site moving spoil. With a PCET scraper-conveyor dirt trap — the trailing C in the model code — a chain-and-flight mechanism lifts the solids out continuously into a chute, so nothing is shut down to clear it. Where the sludge goes is worth settling before anyone quotes: it is a waste stream with its own paperwork.
Send us the condition and we will tell you what satisfies it
If you have a consent condition, a licence clause or an inspector's notice in front of you, send us the wording along with the exit, the vehicles and the peak hour. Our engineers come back with a configuration that answers it and a price — and will say plainly where a rumble grid or a stone access would do the job instead.
Request information
Wheel wash for your site exit
Tell us about the gate and we will come back with a configuration and a budget. No obligation, and no call centre.