If you run a mobile car wash, you're probably leaving money on the table. Undercarriage cleaning is one of the most-requested add-ons in 2026, and most operators either don't offer it or underprice it. Here's how to add it to your service menu and what to charge.

The Quick Answer

Undercarriage cleaning typically runs $35-$75 as a standalone add-on, or $75-$150 as part of a full detail package. The exact price depends on vehicle size, condition, and whether you include an anti-corrosion treatment.

Basic undercarriage rinse (add-on): $35-$50
Full undercarriage wash with degreaser: $50-$100
Undercarriage + rust inhibitor treatment: $100-$150
Fleet vehicles (per unit): $40-$75 depending on volume

This is premium margin work. Your labor time is 10-20 minutes per vehicle, and material costs are minimal.

Why Undercarriage Cleaning Is Worth Adding

Road salt, mud, and grime build up under vehicles all year -- but especially in winter and spring. That buildup accelerates rust on the frame, suspension, and exhaust components. Customers in snow-belt states know this, and they'll pay to prevent it.

The upsell angle is simple: you're already at the car. Adding an undercarriage wash takes 15-20 extra minutes and costs you almost nothing in materials. It's one of the easiest ways to increase average ticket size without adding another stop to your route.

What PSI to Use and How to Do It Right

Undercarriage work needs the right pressure. Too high and you risk damaging suspension components, brake lines, and electrical connections.

Standard passenger vehicles: 1,300-1,900 PSI
Trucks and SUVs: 1,500-2,000 PSI
Never exceed 2,000 PSI on undercarriage components

Start with a degreaser on wheel wells and crossmembers. Let it dwell for 3-5 minutes. Then rinse with your wand at a 45-degree angle, working front to back. Pay extra attention to suspension parts, the area around the fuel tank, and brake calipers.

For rust prevention upsells, apply an anti-corrosion spray after rinsing. Auto-grade rust inhibitor products run $15-$30 per can and cover multiple vehicles per application.

Hot Water Makes a Difference Here

The undercarriage collects grease, road tar, and oil -- not just dirt. Cold water struggles with these. Hot water at 140-160°F breaks down grease molecules faster, reducing your cleaning time by 35-40% on heavily contaminated vehicles.

If you're already running a hot water unit for fleet or commercial work, undercarriage cleaning is a natural add-on. If you're cold water only, you'll still get the job done -- you just need to lean harder on your degreaser and extend your dwell time to 5-7 minutes.

Who to Target

Not every customer needs this service every wash. Focus your pitch on these groups:

Winter-state customers: Anyone driving roads that get salted regularly. Salt is the primary driver of undercarriage rust.
Off-road vehicle owners: Trucks and SUVs that go off-road pack mud into hard-to-reach areas that breed corrosion.
Fleet clients: Companies with delivery vehicles or service trucks care about vehicle lifespan. Undercarriage service on a fleet of 10-20 vehicles is a recurring contract worth $400-$1,500/month.
Pre-sale vehicle owners: People selling their car will pay for a clean undercarriage to pass inspection or impress buyers.

How to Price It in a Package

The most effective way to sell undercarriage service is to build it into a pricing tier, not offer it as a pure add-on. Here's an example menu structure:

Basic wash: Exterior rinse + dry -- $50-$65
Standard detail: Basic + interior vacuum + tire shine -- $90-$120
Premium detail: Standard + undercarriage wash + wheel wells -- $130-$175
Full protection: Premium + rust inhibitor treatment -- $175-$225

Customers respond better to upgrading a tier than paying for individual line items. "Would you like the premium detail for $40 more?" is an easier yes than "Would you like to add undercarriage cleaning for $40?"

Bottom Line

Undercarriage cleaning is high-margin work that most mobile car wash operators overlook. The equipment cost is zero if you already own a pressure washer, material costs are minimal, and customers in winter climates actively want it. Add it to your menu, build it into a tier, and target fleet clients for recurring volume.

If you want to offer instant pricing for your mobile car wash and detail services, try QuoteSnap for free. It puts a self-service quote calculator on your website so customers see your packages and prices before they ever call you.

Undercarriage Pressure Washing: Add This High-Margin Service to Your Menu (2026)