Wash Bay or Mobile Washing: Break-Even Math for 10 to 50 Trucks

Somewhere around 10 units, a fleet manager starts thinking about a wash bay. By the time the fleet reaches 30 to 50, someone in the office builds a spreadsheet on a slow Friday and comes back convinced the bay pays for itself in two years. Sometimes it does. More often the spreadsheet counted the pressure washer and the concrete and left out half of what the bay actually costs.

This post lays out a fair comparison for Metro Atlanta fleets in that 10 to 50 unit range: what it costs to build and permit a bay, what water treatment adds, what the labor really runs, how land and drive time enter the picture, and what mobile washing costs per unit in the local market. The numbers are ranges from the Atlanta market, not anyone's price list, and the goal is a framework you can put your own figures into.

The short version: a bay is a capital project with a permanent operating cost, and mobile washing is a variable cost that scales with the fleet. Which one wins depends on how many units you wash, how often, where they sleep at night, and whether you own the dirt they park on.

What a Wash Bay Actually Costs to Build

A functional truck wash pad is not a slab and a hose. It is a sloped concrete pad sized for a tractor-trailer (roughly 20 by 80 feet minimum), trench drains, an oil-water separator, containment so nothing leaves the pad, water and electrical service, lighting for night work, and either a hot water pressure washer skid or an automatic gantry system. In the Atlanta market, a basic open pad with a separator and a good pressure washer typically lands between $40,000 and $90,000. An enclosed bay with a hot water skid, reclaim system and canopy runs $150,000 to $400,000.

Then there is the paperwork. A pad that discharges to sanitary sewer needs pretreatment approval from the county water authority, and in Douglas and Cobb counties that process involves engineering drawings, a separator spec and inspections. Budget three to nine months from decision to first wash, and expect $10,000 to $30,000 in engineering, permitting and inspection fees on top of construction.

Land is the number most spreadsheets skip. A bay with room to stage two trucks in and two out needs something like 60 by 150 feet of yard. If that yard is owned, the cost is the opportunity cost of not parking eight trailers there. If it is leased, which is common along I-20 and in the Fulton Industrial corridor, the landlord has to approve the improvement, and you leave it behind when the lease ends.

Water Treatment Is the Cost Everyone Forgets

Wash water cannot go to a storm drain, full stop. That means every gallon that hits the pad has to be captured and either sent to sanitary sewer through pretreatment or recycled. A three-stage oil-water separator sized for a truck bay runs $8,000 to $25,000 installed, and it has to be pumped out several times a year at $500 to $1,500 per service depending on volume and what is in the sludge. A full reclaim system that filters and reuses rinse water adds $20,000 to $80,000.

Sewer discharge is metered and billed. A pressure washer wash on a tractor-trailer uses 50 to 150 gallons; an automatic system can use several times that. Forty combos a week at 100 gallons each is over 200,000 gallons a year through the meter, billed as water and sewer. Our post on pressure washing water reclamation covers the recovery side in more depth, but the point for this comparison is that treatment is an ongoing line item, not a one-time build cost.

Labor, Chemicals and Upkeep

Somebody has to wash the trucks. A yard worker at a loaded cost of $18 to $26 per hour, spending 15 to 30 minutes per unit, adds up faster than it looks. A 40 unit fleet washed weekly is 10 to 20 labor hours per week, or 500 to 1,000 hours a year: $10,000 to $26,000 in labor before the supervisor who now manages that person, the training and the turnover.

Chemistry for a two-step wash runs $2 to $6 per unit in bulk. The pressure washer, burner, unloader and separator need service; a realistic maintenance budget for a working bay is $3,000 to $8,000 per year. Add insurance, electricity and burner fuel.

The quieter cost is management attention. A bay becomes the yard supervisor's problem every time the pump goes down or the separator backs up. Those hours never show up on the spreadsheet, and they are real.

The Downtime Cost of Driving to a Bay

If every truck returns to the yard where the bay sits, the drive cost is nearly zero. Many Atlanta fleets are not built that way. A company with one yard in Lithia Springs and a second lot on the far side of I-285 has to send units across the Perimeter to wash, and 20 miles through metro traffic is 45 to 90 minutes of driver time plus fuel. At typical driver and fuel costs, that is $40 to $90 per unit per wash before the wash itself.

Queueing is the other hidden cost. One bay and 40 trucks arriving between 5 and 7 pm on a Friday means drivers sitting in line on the clock, or trucks skipping the wash that week. The bay's theoretical capacity and its real throughput are different numbers.

What Mobile Washing Costs Per Unit

Mobile on-site fleet washing is priced per unit on a recurring route, and in the Atlanta market the ranges are fairly consistent. Vans and box trucks generally run $25 to $60 per wash on a weekly or bi-weekly route, tractors $50 to $90, and tractor-trailer combos $80 to $150 depending on size, frequency and how dirty the fleet arrives. Heavy equipment is usually quoted per piece or per hour. Small stops carry minimums and sometimes trip charges, so a fleet of 10 pays more per unit than a fleet of 40 in the same yard.

That price includes what the bay does not: water, chemistry, hot water, labor, containment and wastewater handling, insurance, and the equipment maintenance. The trade-off is that you depend on a schedule and a provider, weather can move a wash night, and the crew needs access to the yard.

Running the Break-Even

Take a 30 unit mixed fleet washed weekly at an average of $55 per unit. That is $1,650 per week, about $86,000 a year in mobile cost. Now price the bay: $200,000 in capital over a 10 year life is $20,000 a year, labor around $18,000, water and sewer and separator service $8,000, chemistry $6,000, maintenance $5,000. That totals roughly $57,000, and on paper the bay wins by nearly $30,000 a year.

Now add what the paper left out. Land at even a modest opportunity cost of $10,000 to $20,000 a year, drive time if half the fleet sleeps at another lot, permitting and engineering amortized, management time, and the cost of capital on the $200,000 itself. The gap closes to a few thousand dollars either way.

Rules of thumb from that math: below about 20 units, mobile washing wins clearly, because the fixed cost of a bay is spread over too few washes. Between 20 and 40 units it is close, and the decision turns on whether you own a single yard with a sewer connection. Above 40 to 50 units washed weekly at one owned site, a bay can pay, and many fleets at that size run a hybrid: the bay for trailer washouts and emergencies, mobile crews for the weekly exterior route so yard staff stay on their real jobs.

Get the Numbers Before You Pour Concrete

A wash bay is a fine investment for the right fleet and a permanent expense for the wrong one. Before committing capital, run a full year of mobile washing on a defined route and use the invoices as your baseline; they tell you the true per-unit cost, the frequency you actually need, and whether your yard and schedule can support in-house washing at all. That is a cheaper experiment than a slab.

We wash fleets of every size across Metro Atlanta and can share what route data looks like for a fleet like yours. Call (404) 933-8559 or request a quote and we will put real numbers against your spreadsheet.

WASH BAY OR MOBILE WASHING: BREAK-EVEN MATH FOR 10 TO 50 TRUCKS