For groomers: rules

Where does the dirty water go? Waste water and permit rules for mobile groomers

Every bath fills your gray water tank. Here is what cities say to do with it. We also cover groomer permits and flea products.

Short answer: Never let wash water reach a street, gutter, or storm drain. Cities fine groomers for it, up to $10,000 a day in San Diego. Most cities we checked say to empty the tank into a sewer drain. That can be a sink, toilet, or cleanout, with the owner’s OK. Or take it home or to your shop. Rules differ by city, so ask your local stormwater office.

Why storm drains are off limits.

Under federal rules, only rain may go into a storm drain. The EPA says cities with a federal stormwater permit must have a local law against anything else going in. The EPA page doesn’t name groomers. Your city or county law sets the real rule, and many of them do name pet groomers.

What cities say about groomers.

San Diego names pet grooming and can fine up to $10,000 a day for each time. Rancho Santa Margarita, California, gives citations. Marin County, California, says groomers can face criminal charges. It adds that “biodegradable” soap still may not go in a storm drain. Maricopa County, Arizona, names dog groomers in its rules. Boulder County, Colorado, names pets in its rule for mobile washing. Snohomish, Washington, has a program just for mobile pet groomers. Portland, Oregon, bans mobile washing water from its storm drains.

Where you can empty your tank.

San Diego lists three choices. Use a sewer cleanout, utility sink, or toilet at the home, with the owner’s OK. Use a lawn or garden, with the owner’s OK, only if all the water soaks in. Or take the water to a sewer dump station, your shop, or your home. Alameda County, California, says to strain out the fur first. Marin County says to get the OK of both the sewer district and the owner. Laguna Hills, California, says to log where you empty the tank. Don’t use a public manhole without written OK.

You may need a sewer permit.

San Diego and Marin County say you may need a permit to put wash water into the sewer. Portland requires a Mobile Washer Discharge Authorization, for $205 a year. Call the sewer or wastewater office where you work, and the one at your home base.

What about the yard?

Cities don’t agree. Marin County says never send wash water to a yard. San Diego, Rancho Santa Margarita, and Snohomish allow it only if the water has no soap and all of it soaks in. Pet shampoo is soap, so the safe choice is the sewer. Ask your stormwater office before you use a yard.

Cover the storm drain.

Rancho Santa Margarita and Snohomish tell groomers to cover the nearest storm drain downhill before they start. Take the cover off only when you leave. Keep the wash area closed in, so no water runs into the street.

Cities with a mobile groomer permit.

El Monte, California, has a mobile pet grooming permit: $158, plus a $100 license tax for each vehicle. It also asks for insurance that names the city, and it allows grooming from 9 a.m. until sunset. Minneapolis requires a license for pet care from a vehicle, plus liability insurance. Bay Harbor Islands, Florida, asks for a mobile permit. Tamarac, Florida, charges mobile groomers $133.85 per unit for its business tax receipt. Fort Worth, Texas, requires a permit for mobile cleaning businesses. That page doesn’t name pets, so ask the city if it covers you.

Flea shampoo and dips.

The EPA says never pour pesticides down a sink, toilet, or drain, and pet flea products count. Alameda County says leftover flea shampoo should not go down a drain or toilet, or in the trash. Take it to a hazardous waste drop-off. Studies show flea medicine washes off dogs in the bath. A sewer study in Palo Alto, California, found high levels of two flea medicines at a pet groomer’s sewer line. Use only what you need, and keep leftovers in the bottle.

How to find your local rules.

Search for your city’s name plus “stormwater mobile business.” Call your city’s business license office and your wastewater office. Ask about parking too. Cupertino, California, for example, bans commercial vehicles of 10,000 pounds or more from parking on home streets. Write down who you talked to and what they said.

Questions people ask.

Where do mobile groomers dump their water?

Into a drain that goes to the sewer, like a client’s sink, toilet, or cleanout, with the owner’s OK. Or back at the groomer’s home or shop, or a sewer dump station. Never into a street or storm drain.

Can mobile groomers dump water on the grass?

It depends on the city. Some allow it only if the water has no soap and all of it soaks in. Marin County, California, says never. Pet shampoo is soap, so ask your stormwater office first.

Do mobile groomers need a special permit?

Some cities require one. El Monte, California, Minneapolis, Bay Harbor Islands, Florida, and Tamarac, Florida, name mobile groomers or mobile pet care. Most places only need a regular business license. Ask your city.

Is biodegradable shampoo OK in a storm drain?

No. Three places in California say so: Marin County, San Mateo, and Alameda County. Soap that says “biodegradable” or “nontoxic” still may not go in.

What happens if a groomer dumps water in the street?

Cities can fine you. San Diego’s fines go up to $10,000 a day, and Fort Worth’s go up to $2,000 each time.

Where these facts come from.

We read each page on November 3, 2026. Rules change and differ by place. This is not legal or tax advice.

Next steps.

Written by Fluffmobile. Updated November 3, 2026. This is general advice, and every groomer has their own rules.

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