“Can I let the wash water run into the street?” Picture the end of the driveway you just cleaned. The water runs to the gutter, the gutter runs to a grate, and the grate is the top of a pipe that ends at a creek. The stormwater guide published by the Sacramento-area stormwater agencies puts it plainly: the storm drain system carries water directly to local creeks and rivers and is not treated in any way to remove pollutants.
That is why wash water in a storm drain is treated as a discharge, and why federal law and your city’s ordinance both have something to say about it. This article explains where the rule comes from, how to capture the water, where it may go, and why the label on your cleaning product is part of the same rule.
The storm drain is not the sewer
There are two pipe systems under the street. The sanitary sewer carries wastewater from sinks, toilets and washing machines to a treatment plant. The storm drain carries rain and irrigation water off streets and neighborhoods to nearby creeks and rivers. WSSC Water, a Maryland water and sewer utility, and the Sacramento guide describe the difference in almost the same words, and both add a line every pressure washer should remember: virtually all outdoor drains in streets, parking lots and elsewhere are storm drains, which may not be used for wastewater disposal.
What is in the water matters too. The EPA says runoff picks up pollutants like trash, chemicals, oils and dirt that can harm rivers, streams, lakes and coastal waters. Wash water carries whatever you just took off the surface, plus whatever you sprayed on it. The Sacramento guide lists heavy metals, chemicals, and oil and grease from cleaning compounds and from the surfaces being cleaned.
Where the rule comes from
The federal rule. Section 301(a) of the Clean Water Act is one sentence: except in compliance with the Act’s sections, including its permit program, “the discharge of any pollutant by any person shall be unlawful” (33 U.S.C. §1311(a)). WSSC’s guidance for mobile washers spells out what that means for you: to discharge wash water legally, an operator would need an NPDES permit for each discharge location, which is not realistic for a mobile business, and permitted process discharges usually require treatment and testing as well.
The local rule. Most of the time the rule you actually meet is your city’s or county’s. Under the EPA’s stormwater rules, the operator of a regulated small municipal storm sewer system must, to the extent state, tribal or local law allows, effectively prohibit non-stormwater discharges into its system through an ordinance or other regulatory mechanism, and enforce it (40 CFR §122.34(b)(3)). An illicit discharge is any discharge to a municipal separate storm sewer that is not composed entirely of storm water, apart from discharges under an NPDES permit and discharges from fire fighting (40 CFR §122.26(b)(2)), and the storm sewer system itself is defined to include roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches and storm drains (§122.26(b)(8)).
The rule names some flows a city need only address if they turn out to be significant sources of pollutants: lawn watering, landscape irrigation, individual residential car washing, street wash water and a few others. Commercial pressure washing is not on that list. The EPA’s fact sheet on these programs adds that illicit discharges are considered illicit because storm sewer systems are not designed to accept, process or discharge such wastes.
Local ordinances differ in their details and their penalties. The Sacramento guide, as one example, says every local stormwater ordinance in its area prohibits discharging pressure washing wastewater to the storm drain system, which it defines to include storm drains, roadside ditches, gutters, streets and sidewalks. It also prohibits letting wash water evaporate on pavement, because the residue washes into the drains with the next rain. It says violations can bring fines of up to $5,000 per day, and that a business that hires a contractor may itself face enforcement if the contractor disposes of wash water illegally on its property. That guide was last revised in 2011, so read your own area’s current ordinance rather than relying on its numbers.
Plan the water before you start
The Sacramento guide’s basic steps work anywhere:
- Pre-plan. Get any permits the disposal needs, find every storm drain the water could reach, decide how you will contain and collect it, choose the disposal option, and get the property owner’s permission to use an on-site disposal point.
- Pre-clean dry. Sweep first, and treat oily spots with absorbent before any water goes down, keeping the debris out of the drains.
- Work the site. Block or protect the drains, find the low spot where water will pool for pickup, and use no more water than the job needs.
- Collect it. Contain and pick up the water as you go.
- Dispose of it properly, by a method that fits what is in the water.
The guide lists the usual equipment: vacuum booms that both block and pick up, temporary berms (which it says must be watched constantly), storm drain covers and mats, inflatable plugs for the pipe below a drain inlet (on private property only, with all water kept on site), portable containment pools, wet/dry vacuums, and a small pump and hose, attended and put away daily.
Where the collected water may go
The Sacramento guide names four compliant routes; WSSC’s guidance for its own service area names the sewer and a licensed hauler:
Know when water may be hazardous before you make it. The Sacramento guide warns that cleaning with strong acids or caustics, or cleaning surfaces with lead-based paint or built-up antifreeze, oil and grease or solvents, can produce wastewater classed as hazardous waste. WSSC adds that washing building exteriors painted before 1978 may wash off lead, and that parking lots and gas stations may carry oil, solvents and metals. The Sacramento guide also forbids sending wash water to a septic system without prior approval.
The label is part of the law
Look at the product you use against mold, mildew or algae. U.S. law requires EPA to register all pesticides, and the EPA’s guide to reading a pesticide label lists the EPA registration number among the label’s parts, with the directions for use and the storage and disposal instructions. If your product shows one, it is a registered pesticide. Federal law makes it unlawful to use a registered pesticide in a manner inconsistent with its labeling (7 U.S.C. §136j(a)(2)(G)), which the EPA shortens to “the label is the law.” The EPA says the label sets out who may use the product and where, how, how much and how often.
WSSC’s guidance makes the link to wash water directly: read cleaning product labels before disposing of wash water, and follow the use and disposal instructions carefully. The Sacramento guide adds two habits that cut cost as well as risk: choose less toxic cleaners where they do the job, and never mix wash water that may be hazardous with water that is not, because that can make the whole load hazardous waste, with fewer disposal options and a higher bill.
Price it in, and find your local rule
Containment, pickup and disposal take time and equipment, so they belong in the price, not in your margin. At the quote, ask where the nearest drains are and whether there is a cleanout or utility sink you may use. Pressure washing prices by surface shows where those minutes go in a rate card, and the pressure washing page covers the trade more broadly.
Then spend an hour this week on three lookups: your city or county stormwater program’s rules for surface cleaning, your sewer utility’s conditions for discharges from mobile washers, and your state environmental agency’s rules for hazardous waste. Write the answers on one page and keep it in the truck.
General information, not legal or tax advice. Rules change and vary by state; check with the agency named above or a professional for your situation.