The 6H lanes: where a mobile operator can spray
The federal rule is 40 CFR 63 Subpart HHHHHH — "6H" in shop talk. It exists to keep the heavy metals in refinish coatings (cadmium, chromium, lead, manganese, nickel) out of the air. For spray-applied work it requires a ventilated, filtered enclosure, HVLP or equivalent guns, and painter training — which is why full-panel respray is booth territory, not driveway territory.
The lanes that stay open to a mobile SMART operator, per state 6H guidance like North Carolina's: brush, roller, paint pen, and aerosol work aren't spray-applied under the rule, and neither is a handheld gun fed from a cup of 3 fluid ounces or less. One catch EPA has put in writing — refilling that little cup over and over to sneak a big job through counts as circumventing the rule.
Doing spray work under the rule carries its own duties beyond the equipment: painter training and certification, an initial notification filing to EPA or the delegated state agency, and periodic filter maintenance — the shop-level obligations 6H sources own. And the mess is regulated too: sanding residue, masking, and paint or solvent waste go to an authorized facility, never a drain or the ground.
Then the local layer. Cities, residential zoning, and regional air districts restrict mobile spray work in ways the federal rule doesn't. Check yours before you offer it, not after a complaint.
The repair paper: estimate first, then authorization
Body and paint work for pay is regulated auto repair in several states. California's Bureau of Automotive Repair registers repair dealers — mobile operators included — and its 2025 estimate rules tightened what an estimate and invoice must spell out: specific descriptions of the work, in plain language, authorized before work begins, with any increase re-authorized.
That's not just a California habit. A written estimate the customer said yes to — with the amount, the name, and the time — is the record that ends the "I never agreed to that" conversation everywhere.
Authorization you can point to
The customer approves the itemized estimate from their phone; the name, amount, and time print on the document. If the job grows, SideWRK warns you when the running total passes what was authorized — so you re-authorize before the extra work, not after.
Photos before you touch it
Time-stamped pre-work photos of the damage and any prior bodywork ride with the job. On blends over aged paint, that's your color-match disclosure backup.
VIN, paint code, parts condition
The vehicle record holds the VIN and details; every part line carries its condition — new, used, customer-supplied — right on the invoice.
Registration number on the document
Your BAR/ARD or state registration number prints on every estimate and invoice, along with the auto body trade notices — including the 6H enclosure statement for any spray-applied work.
Straight talk
SideWRK documents the job — it does not determine whether your setup meets 6H, your city's zoning, or your state's registration rules, and it doesn't verify any registration number you enter. Waste handling, air districts, and mobile-spray restrictions vary block by block.
This page is not legal advice. The federal rule, your state's repair-dealer law, and your local air district are the authority.
Mobile auto body — common questions
Can I legally spray paint cars as a mobile business?
Under the federal EPA 6H rule, spray-applied refinishing must happen with HVLP (or equivalent) equipment inside a ventilated, filtered enclosure by a trained painter. Work that is not spray-applied sits outside those requirements — brush, roller, paint pen, aerosol can, and spray guns with a cup of 3 fluid ounces or less. Cities, residential zones, and air districts add their own restrictions, so local rules can say no even where the federal rule says yes.
What is the 6H 3-ounce cup exemption?
Coatings applied from a handheld device with a paint cup of 3 fluid ounces or less are not treated as spray-applied under 40 CFR 63 Subpart HHHHHH, so small-cup touch-up and mobile spot work can operate outside the rule's spray requirements. EPA has said that repeatedly refilling a 3-ounce cup to do a bigger spray job counts as circumventing the rule — the exemption covers genuinely small repairs, not a full panel fed 3 ounces at a time.
Do I need a written estimate before starting body work?
In states that regulate auto repair, yes. California requires repair dealers — mobile operators included — to register with the Bureau of Automotive Repair and to give the customer a written, itemized estimate covering parts and labor that is authorized before work begins, with any increase authorized again before the extra work. Even where it is not required, a logged authorization is the record that settles most disputes.
What records should a mobile operator keep on each job?
The vehicle's VIN and paint code, time-stamped photos of the damage and any prior bodywork before you touch it, the written estimate and the customer's authorization with name, amount, and time, itemized parts with their condition (new, used, customer-supplied), and notes on color-match limits for blends over aged paint. SideWRK captures each of these on the job; it does not determine whether your work meets any air-quality or registration rule, and this is not legal advice.