Where Does the Dirty Water Go? NYC Wastewater and Storm Drain Rules for Power Washing
Quality Power Wash Team | August 2026
A crew spends a morning washing your sidewalk, your loading dock or your parking area, and several hundred gallons of water carrying grease, oil and chemistry goes somewhere. In New York City, none of it may legally go into a storm sewer, catch basin or manhole, and the rule reaches the property owner as well as the contractor. It is the question almost no property manager asks and almost no contractor volunteers.
Here is what the rules actually say, who they land on, and what compliant work looks like on site.
The Rule, and Which Rule It Actually Is
You will find plenty of trade articles claiming the EPA or the Clean Water Act prohibits wash water in storm drains. In New York City that is the wrong citation, and citing it usually means the writer copied an article written for somewhere else.
The rule here is 15 RCNY 19-02. It states that no person shall discharge or cause to be discharged, directly or indirectly, into any storm sewer any substance other than stormwater or allowable runoff, and it applies the same prohibition to any catch basin or manhole.
Three phrases in that sentence do most of the work. No person, which means it does not matter whether you or your contractor did it. Indirectly, which means letting water run down a slope toward a catch basin counts as much as putting a hose into one. And other than stormwater, which is the part people misread: wash water from a commercial cleaning job is not stormwater, no matter how much of it is water.
Why New York Is Written This Way
Much of the city runs a combined sewer system, where sanitary and storm flows share the same pipe, but a substantial portion runs separate storm sewers that discharge to the harbor, the rivers and the creeks with far less treatment. From the street you cannot tell which one you are standing over. A catch basin looks the same either way.
That is the practical reason the rule is absolute. The contractor rinsing a dumpster pad has no idea whether that grease is heading to a treatment plant or to Newtown Creek, so the rule removes the guesswork by prohibiting the discharge outright.
What Compliant Work Actually Looks Like
This is the part worth knowing, because it is how you tell a commercial operator from someone with a machine.
- The work area is contained before anything is turned on, using berms, booms, mats or dams depending on the surface and the slope
- Drains inside and downhill of the work area are blocked or bagged, and that includes trench drains, not only the obvious catch basin at the curb
- Water is recovered, typically by vacuum, rather than allowed to find its own way
- Solids and debris are separated out and disposed of as waste, not washed into anything
- Recovered water is disposed of through a permitted route
- The crew knows before they start where the water is going, and can tell you
On the disposal question, two permits matter and you are entitled to ask about both. Transporting recovered wash water off site in New York State requires a waste transporter permit under 6 NYCRR Part 364. Discharging industrial wash water into a sanitary connection can require a DEP Industrial Wastewater Discharge Permit under 15 RCNY 19-05. A contractor who says they simply dump it is describing an unpermitted activity.
Want to know exactly where your wash water goes?
We contain, recover and dispose of wash water on every commercial job across the five boroughs, and we will tell you how before we start. See our pressure washing services. Call 718-986-8129 or request a free quote.
718-986-8129
Where the Water Comes From, Too
The other half of the question. Most commercial units carry their own water in a tank, which is the simple case. On a large job that needs more, contractors sometimes draw from a fire hydrant, and that is regulated as well.
A DEP permit to use a hydrant runs 55 dollars for each 30 day period plus a water charge of 13.50 dollars per day, and it requires a reduced pressure zone backflow preventer installed by a licensed master plumber, with the device serial and model recorded on the application. The backflow preventer is the important part: it is what stops contaminated water being drawn back into the public supply.
If a crew is on your property pulling from a hydrant, the permit and the backflow device are fair things to ask to see. Unpermitted hydrant use is not a paperwork oversight, it is a public water supply issue.
When You Are Allowed to Wash the Sidewalk at All
Separate rule, same theme, and this one catches almost everyone. Under 15 RCNY 20-08(a)(7) and Administrative Code 24-332, flushing a sidewalk is prohibited between 11 in the morning and 7 in the evening, and flushing a sidewalk by means of a hose or piping is prohibited between November 1 and March 31. DEP enforces it, and an inspector has to observe it personally for a summons to issue.
The narrow exception is washing required as part of repairs mandated by the Administrative Code, or to protect public health and safety. Routine cleaning is not that.
Rule | What it restricts | Who it lands on |
|---|---|---|
15 RCNY 19-02 | Any discharge to a storm sewer, catch basin or manhole other than stormwater or allowable runoff | Any person, in practice the property |
15 RCNY 20-08(a)(7) and Admin Code 24-332 | Sidewalk flushing 11 a.m. to 7 p.m., and by hose from November 1 to March 31 | Whoever is doing the flushing, observed by DEP |
6 NYCRR Part 364 | Transporting recovered wash water off site without a permit | The transporter |
15 RCNY 19-05 | Industrial wash water into a sanitary connection without a permit | The discharger |
So public sidewalk washing in New York City is an April through October service, done early in the morning or in the evening. That is not a limitation a good contractor hides from you, it is a scheduling fact they build the annual plan around, moving the winter work to surfaces that are not public sidewalk: entries, private forecourts, courtyards, loading areas, garages and facades.
Noise, While We Are Listing Constraints
Early morning is the right window for most commercial exterior work, but it runs into the noise rules. New York City generally permits construction noise between 7 in the morning and 6 in the evening on weekdays, with after hours work requiring authorization. In practice that squeezes public sidewalk work into a narrow band between 7 and 11 in the morning, which is exactly why commercial exterior schedules are built weeks ahead rather than booked on demand.
How This Becomes Your Problem
The pattern is consistent. A contractor is engaged, does the work, and leaves. A DEP inspector observes a discharge, or a neighbor complains, or a catch basin backs up with grease. The inspector is standing in front of your building. The summons names the property, and the person in charge of the premises is the respondent.
Whatever your contract says between you and the contractor, sorting it out afterward is your time and your problem. The cheaper fix is to ask the question before the work starts. Our guide to vetting a commercial power washing contractor has the full list.
What to Ask
- Where does the wash water go on this job?
- How will you contain the area and which drains will you block?
- Do you recover the water, and with what?
- How is it disposed of, and under what permit?
- Are you drawing from a hydrant, and if so can we see the permit and the backflow device?
- What is your schedule for the public sidewalk portion, given the seasonal and hourly restrictions?
A commercial operator answers all six without pausing. If the answer to the first one is that it is just water, you have learned what you needed to know.
Final Thoughts
In New York City the authority on wash water is 15 RCNY 19-02, not the EPA. Nothing but stormwater or allowable runoff may go into a storm sewer, catch basin or manhole, directly or indirectly. Sidewalk flushing is separately restricted to outside 11 to 7, and prohibited by hose from November through March. Recovered water needs a permitted disposal route, and hydrant draw needs a permit and a backflow preventer.
All of it lands on the property when it goes wrong, which is the whole reason to ask before the work starts rather than after.
Frequently Asked Questions
Can wash water go down a storm drain in New York City?
No. 15 RCNY 19-02 provides that no person shall discharge, directly or indirectly, into any storm sewer any substance other than stormwater or allowable runoff, and applies the same prohibition to catch basins and manholes. Commercial wash water carrying grease, oil or cleaning chemistry is not stormwater.
Is it the EPA or the Clean Water Act that governs this?
Not in New York City. Trade articles routinely cite the EPA because they are written for other jurisdictions. The operative rule here is 15 RCNY 19-02, enforced by the Department of Environmental Protection.
Who gets the violation, us or the contractor?
The rule reaches any person who discharges or causes a discharge, and in practice a summons is issued at the property where the discharge is observed, naming the person in charge of the premises. Sorting out responsibility with your contractor afterward is a separate and slower process.
What should a contractor do with the dirty water?
Contain the work area, block or bag the drains including trench drains, recover the water rather than letting it run, separate out solids, and dispose of it through a permitted route. Transporting it off site in New York State requires a waste transporter permit under 6 NYCRR Part 364.
Can a contractor take water from a fire hydrant?
Only with a DEP permit. It runs 55 dollars for each 30 day period plus a water charge of 13.50 dollars per day, and requires a reduced pressure zone backflow preventer installed by a licensed master plumber, with the device serial and model recorded on the application.
When can a sidewalk be washed in New York City?
Outside the hours of 11 in the morning to 7 in the evening, and only between April 1 and October 31, since flushing a sidewalk by hose or piping is prohibited from November 1 through March 31 under 15 RCNY 20-08(a)(7) and Administrative Code 24-332.
Booking exterior cleaning for your property?
Quality Power Wash contains, recovers and disposes of wash water on every commercial job across the five boroughs, and we will tell you exactly how before we start. Call 718-986-8129 or request a free quote.
718-986-8129