In most of the US, the water that runs off a fleet wash can’t go into a storm drain, a street, a gutter or a ditch. You collect it and send it to the sanitary sewer with the sewer utility’s OK, or you haul it away. A few places let it soak into the ground when you’re off pavement. The details are local, so the first job at any new yard is a phone call.
Why the storm drain is the problem
A building’s sinks and floor drains go to the sanitary sewer, which ends at a treatment plant. The grate in the parking lot is a different pipe. It was built to move rain off the pavement, and it ends at the nearest creek, river or lake with nothing in between. Alameda County’s Clean Water Program says it about its own storm drains. The water “travels directly to local creeks and then to San Francisco Bay. It does not go to a wastewater treatment plant.”
Wash water carries whatever was on the truck. Gwinnett County, Georgia names sediment, nutrients, organic matter, oil and grease, heavy metals, trash, detergents and cleaning agents as the pollutants it’s worried about in fleet wash water.
What the federal law says
The Clean Water Act is the base. As EPA puts it, the Act prohibits anybody from discharging pollutants through a point source into a water of the United States unless they have an NPDES permit. A storm drain that empties into a creek is a way into those waters.
Cities that hold a storm sewer permit have to find and stop illicit discharges. The federal rule lists a few flows a city can leave alone unless it finds they’re causing pollution, and “individual residential car washing” is one of them. Commercial washing isn’t on the list. That’s why a neighbor can wash a pickup in the driveway and you can’t wash forty tractors over the same kind of drain.
States and cities add their own rules. Georgia’s industrial stormwater permit says fleet washing discharges into stormwater aren’t authorized. Portland, Oregon bans commercial mobile wash water from “the City’s stormwater system, streets, or right-of-way.”
What it can cost you
The federal ceiling for a Clean Water Act civil penalty is $68,445 per day for each violation. That’s the figure in EPA’s penalty table for penalties assessed on or after January 8, 2025. Cities and states set their own fines too, and it’s their stormwater staff who watch mobile washers day to day. The customer hears about it either way, because it happened on their lot.
Three places wash water can go
1. The sanitary sewer, with permission
EPA says you don’t need a federal permit to discharge into a municipal sanitary sewer, “but you should ask the municipality about their permit requirements.” Some want a permit or a written authorization, and they set limits. Portland’s Mobile Washer Discharge Authorization shows what a city can ask for.
- An application, then a yearly certification that you’re following the rules.
- A work plan and a drainage map for each customer’s property.
- Water collected and discharged “at an approved location.”
- pH between 5.0 and 11.5, checked on site.
- No more than 50 gallons a minute going in.
- Greasy wastewater run through an approved grease removal device first.
- Possible treatment for pH and metals if you use brighteners.
- Exterior washing only. Tank and tanker interiors aren’t covered.
Some fleet yards already have a wash bay or a drain that’s plumbed to the sanitary sewer. Ask the customer before you plan anything else.
2. A tank, hauled off
Gwinnett County gives two choices for soapy wash water, “a holding tank truck or sanitary sewer in accordance with local wastewater requirements.” If you haul it, you still need a legal place to empty the tank, so the call to the sewer utility still applies.
3. The ground, in some places
Off pavement, some places let wash water spread out and soak into grass or gravel. Gwinnett allows it even with soap, as long as the water doesn’t reach the storm system or a stream and doesn’t kill the grass. Don’t assume your county agrees.
What a compliant wash looks like
These steps come from the Gwinnett County and Alameda County guidance. Your city’s list may differ, so read it.
- Call the stormwater agency and the sewer utility before the first wash. Ask what your options are.
- Find every storm drain near the wash area and cover it with a mat, a plug or a berm. Alameda County wants the wash area flat and at least 25 feet from any storm drain.
- Sweep first and put absorbent on oil spots, so less ends up in the water.
- Contain the water with berms or a wash mat.
- Pick it up with a sump pump or a wet vacuum, and send it to the sewer or your tank.
- Use the least toxic product that does the job.
- Don’t leave soapy water on the pavement to dry. Gwinnett’s reason is that the residue goes down the storm drain with the next rain.
- Don’t wash when it’s raining or about to.
- Check the drain covers when you’re done and clean up the solids.
Water with no soap in it gets lighter treatment in some places. On pavement, Gwinnett asks for a filter insert in the catch basin to trap the solids. Other cities don’t allow any wash water in the storm drain, so ask.
Who’s responsible, you or the customer?
Both can be. Alameda County says mobile fleet service providers “are responsible for any activities that lead to non-stormwater discharges to the street, gutter or storm drain.” It also puts a duty on the property owner, who has to set up a marked wash area. Before the first wash, settle in writing where you’ll wash, where the water goes, and who holds the permit if there is one.
Price it in
Recovery adds equipment and minutes at every stop. One published startup estimate puts a water reclamation and filtration unit at $4,000 to $12,000. Covering drains, laying a mat, vacuuming and emptying the tank all take time on site. Put that time into your per-unit price at the yards that need it, or put recovery on its own line.
Common questions
Can fleet wash water go down a storm drain?
Almost never. Storm drains run to creeks and rivers with no treatment, and the Clean Water Act and local codes ban commercial wash water from them. Collect it and send it to the sanitary sewer with the utility’s approval, or haul it off.
Do I need a permit for mobile fleet washing?
It depends on the city. You don’t need a federal NPDES permit to discharge into a sanitary sewer, but many sewer utilities want a permit or a written authorization first. Portland, Oregon requires a Mobile Washer Discharge Authorization and a yearly certification.
What’s the fine for letting wash water into a storm drain?
The federal maximum civil penalty under the Clean Water Act is $68,445 per day for each violation, for penalties assessed on or after January 8, 2025. Cities and states set their own fines as well.
How The Wash Book does it
In The Wash Book each yard carries its own notes and flags, like water reclaim required, and the crew sees them on the job before they start. Book a demo and we’ll walk you through it, or start free with unit tracking.
Sources
- EPA, NPDES Permit Basics
- 40 CFR 122.26, storm water discharges (illicit discharge programs)
- 40 CFR 19.4, civil penalties adjusted for inflation
- City of Portland, Guide to the Mobile Washer Program
- Gwinnett County Department of Water Resources, Mobile Vehicle & Fleet Washing (PDF)
- Alameda County Clean Water Program, Tips for Mobile Fleet Services Providers (PDF, 2022)
- ZenBusiness, How to Start a Fleet Cleaning Business (startup cost table)