Why the storm drain is off limits

A storm drain is not a sewer. The EPA says polluted runoff in city storm systems is often discharged, untreated, into local water bodies. One city’s brochure says wash runoff can carry metals such as copper, lead and zinc, plus oil and grease. The federal Clean Water Act made it unlawful to discharge any pollutant from a point source into navigable waters unless a permit was obtained. The EPA also says certain storm system operators must get permits and run stormwater management programs. Local rules often come out of those programs, so they vary.

What two cities actually say

Both cities below bar polluted wash water from storm drains, but they differ on the details. These are summaries; read the originals before you rely on them.

Rancho Santa Margarita, California. The city’s mobile detailer brochure says it is unlawful for mobile detailers’ wash water to enter storm drains. It says detailers who do not prevent wash water from entering the storm drain are subject to administrative citations and/or fines, and that mobile detailers must use these practices:

  • Contain the wash area with sandbag berms, wattles or bermed mats.
  • Protect the downstream storm drain inlet before you start washing, and remove the protection before you leave.
  • Use a wet-vac to pick up wash water for proper disposal.
  • Vacuum or shake floor mats into a trash can.

Its preferred option is zero discharge or closed-loop recycled water. The second option is the municipal sewer, such as a residential cleanout, utility sink or toilet, with care to keep out debris and hazardous material. It also says wash water may be taken off site for proper disposal.

Austin, Texas. The city’s water utility says its power-washing wastewater rules also apply to mobile car washes. Wastewater that contains pollutants or cleaning compounds and has not been treated may not go into the storm sewer. It may go to the sanitary sewer under certain conditions: it must be collected and taken to a private fixed-site facility connected to the city sewer. To set up that facility you must apply for a discharge permit and have pretreatment such as a sand/oil interceptor or grit trap. The city says landfills and treatment facilities may also accept hauled liquid waste.

Austin also lists prohibited disposal sites. Hauled industrial wastewater may not be dumped into a cleanout, manhole or toilet at the site being cleaned unless that site is permitted by the city water utility and has an appropriately sized sand/oil interceptor. The city says unauthorized discharge into its sanitary sewer is a Class C misdemeanor punishable by a fine of up to $2,000 per day per violation. It tells operators to contact its utility compliance division before they start.

The gap: a customer’s toilet is listed as an option in one city and restricted in the other. That’s the main reason to check local rules rather than copy another detailer’s setup.

Your options, from cheapest to most complete

  1. Make less water. A rinseless wash leaves little to catch. Our guide on how to start a mobile detailing business prices a rinseless starter setup.
  2. Catch and haul. Berms or a mat hold the water, and a pump or wet-vac moves it to a tank.
  3. Catch and recycle. A reclaim unit filters the water for reuse, the closed-loop option Rancho Santa Margarita prefers.

Common gear, as listed on October 8, 2026:

Gear Example product and seller Listed price
Inflatable berm, 10 ft Latimat LPWD10 dike berm (Dultmeier) $150
Sump pump for captured water GJ 5MSP, 115 V (Dultmeier) $173
Small mat for engine bays, 4 x 5 ft Engine compartment containment mat (Detail King) $449
Car-size mat, 10 x 20 ft Latimat LWP1020F4 wash pad (Dultmeier) $1,070
Car-size mat with foam berm Water Containment Mat w/ Foam Berm (Detail King) from $1,595
Wash water tank system Mr Green’s Wash Water Tank System (Detail King) $799.95
Reclaim unit, 15 gallon Big Dog 15 Gallon Water Reclamation System (Detail King) $1,995
Reclaim unit, 30 gallon with auto pump-out Big Dog 30 Gallon system (Detail King) $3,395
Vacuum reclaim and filtration Vacuum Reclamation & Filtration System (Detail King) $5,995

A 10-foot berm and the sump pump together come to $323, before hose. One distributor says its mat warranty is void if a mat is punctured without an underlay, and rough surfaces always need one. Its 10 x 10 ft underlay lists at $109. Prices change often.

Before you take a job in a new city

Ask the city’s stormwater or public works office:

  • Can any wash water, even plain rinse water, reach the storm drain?
  • Do I need a permit or business license to wash vehicles here?
  • Where may I dispose of captured water?
  • What are the penalties?

Build the cost into your prices

Containment adds gear, setup time and disposal trips. Count all three when you work out how much to charge for mobile detailing. A big truck needs more mat, so price by vehicle size too.

Customers ask how the job works at their home, so a clear water plan helps. Our guide to finding a reliable mobile detailer shows what they check. See our methodology for how we check prices.

Sources