Mobile Car Wash Business: LLC vs. S-Corp, Tax Structure, and QBI Deduction

By Yarik Yarosh, CPA ·September 5, 2026 ·4 min read

Written by Yarik Yarosh, CPA (US & Canada) September 5, 2026 · FL CPA license AC61704 · CPA Ontario

A mobile car wash (or mobile detailing) business brings washing, detailing, and sometimes paint correction services directly to the customer’s location. The business is NOT a Specified Service Trade or Business (SSTB) under IRC 199A, meaning the full 20% QBI deduction applies at all income levels. The cost structure is highly favorable: water, soap, chemicals, and towels run only 5-10% of revenue, making this one of the lowest-cost-of-goods businesses in any trade. Equipment investment is moderate ($3,000-$15,000 for a pressure washer, water tank, generator, and supplies), and a vehicle with a water tank setup ($10,000-$40,000) is the largest capital investment. Margins are exceptional (75-90% for basic washes, 65-80% for full details) because the service is almost pure labor plus minimal supplies.

✓Key takeaway

Mobile car wash tax profile:

SSTB classification: NOT an SSTB

Car washing and detailing is a trade service
Full QBI deduction at all income levels
No phase-out above $266,950 (single) / $533,900 (MFJ)

Revenue model:

Basic exterior wash: $30-$60
Full detail (interior + exterior): $150-$300
Paint correction/ceramic coating: $300-$1,000+
Fleet/commercial accounts: $20-$40/vehicle (volume pricing)
Recurring customers (subscription model): $50-$100/month
Average daily revenue (solo): $300-$600 (5-8 vehicles/day)

Cost structure (% of revenue):

Water, chemicals, soap: 3-5%
Towels, applicators, supplies: 2-5%
Vehicle operating (fuel, insurance, maintenance): 8-12%
Equipment maintenance: 1-2%
Net margins: 75-90% (basic wash), 65-80% (full detail)

Major investments:

Equipment	Cost	Section 179
Van/truck with tank setup	$10,000-$40,000	Yes (over 6,000 lbs)
Pressure washer (commercial)	$2,000-$5,000	Yes
Water tank (100-300 gallon)	$500-$2,000	Yes
Generator	$1,000-$3,000	Yes
Polisher/buffer	$300-$800	Yes
Vacuum (commercial)	$500-$1,500	Yes
Canopy/tent	$200-$500	Yes
Total setup	$15,000-$53,000

S-Corp analysis:

Very low supply costs mean more profit flows to the bottom line
S-Corp break-even: approximately $55,000-$65,000 in net profit
At $80,000 net: S-Corp saves approximately $2,500-$3,500/year
Reasonable salary: $30,000-$45,000 (based on employed car wash worker wages, adjusted for mobile premium)
The low overhead makes S-Corp attractive at lower profit levels than most trades

How should a mobile car wash be structured for taxes?

Hypothetical example

Round numbers. A solo mobile detailing operator. Year 2. Single filer. Works 250 days per year.

Revenue: $120,000

Basic washes (200 at $40 average): $8,000
Full details (400 at $200 average): $80,000
Paint correction/ceramic (40 at $500 average): $20,000
Fleet accounts: $12,000

Expenses: $16,000

Vehicle operating (van, fuel, maintenance): $7,000
Chemicals and supplies: $4,000
Insurance: $2,000
Phone/marketing: $2,000
Equipment maintenance: $1,000

Net profit: $104,000

Sole proprietorship:

SE tax: $104,000 x 92.35% x 15.3% = $14,688
QBI: $104,000 x 20% = $20,800
Taxable: $104,000 - $7,344 - $15,000 - $20,800 = $60,856
Income tax: $8,515
Total: $23,203
Effective rate: 22.3%

S-Corp ($40,000 salary):

FICA: $40,000 x 15.3% = $6,120
QBI: $64,000 x 20% = $12,800
Taxable: $104,000 - $15,000 - $12,800 = $76,200
Income tax: $11,340
S-Corp costs: $2,200
Total: $19,660
Effective rate: 18.9%

S-Corp saves: $3,543/year

Reasonable salary justification:

Employed car wash workers earn $25,000-$35,000/year
Mobile premium: $5,000-$10,000 (specialized skills, own schedule)
$40,000 is reasonable for the personal service component
The remaining $64,000 reflects business reputation, vehicle investment, customer relationships
Document with job listings for car wash/detailing employees in your city

Year 1 equipment deduction: Van ($30,000 over 6,000 lbs) + equipment ($10,000) = $40,000 Section 179 Year 1 net: $90,000 - $14,000 - $40,000 = $36,000 Year 1 tax: $5,800

Year 2 net: $104,000 Year 2 tax: $23,203 Jump: $17,403 (4x increase)

Ceramic coating as a margin driver:

Service	Price	Supply Cost	Margin
Basic wash	$40	$3	93%
Full detail	$200	$15	93%
Ceramic coating	$500	$50	90%
Paint correction + ceramic	$800	$70	91%

Ceramic coatings cost $30-$80 in product for a $400-$800 service. The ROI on ceramic coating certification ($500-$1,500) is extraordinary: 10 ceramic jobs at $500 = $5,000 revenue on a $1,000 investment (5x in the first month). The certification itself is a deductible business expense.

Subscription/membership model: 10 monthly subscribers at $80/month = $800/month = $9,600/year guaranteed revenue. This recurring revenue:

Smooths seasonal income (car washes are mildly seasonal)
Makes estimated tax planning easier (predictable baseline)
Increases business valuation (recurring revenue commands a premium)

Illustrative numbers only, not a real client and not advice for your facts.

Related guides:

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Cite this page

Yarik Yarosh, CPA. "Mobile Car Wash Business: LLC vs. S-Corp, Tax Structure, and QBI Deduction." Blue Cloud CPA, September 5, 2026. https://bluecloudcpa.com/guides/mobile-car-wash-entity-structure-scorp

This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.