Home › Blog › How to Remove Oil Stains from Concrete
Published July 17, 2026 · By PowerWashingExpert Field Team · ~8 min read
Quick answer: Pressure washing alone will not remove an oil stain, because oil and water do not mix. Apply a concrete degreaser, scrub it in, let it dwell, then flush with hot-water pressure washing around 3,000 PSI. For old, set-in stains, draw the oil out with a poultice left on for about 24 hours. Fresh spills come out almost fully; deep stains may leave a shadow, which sealing afterward helps prevent next time.
Oil stains are the most common thing we get called about on concrete in Metro Detroit. A leaking car on a driveway, a delivery truck on a loading apron, a dumpster pad behind a restaurant, a fleet parked on the same slab every night. The dark blotches make a property look neglected, and on a commercial lot they are a slip liability too. The good news is that most oil comes out if you attack it the right way. The bad news is that the way most people try, blasting it with a pressure washer, does almost nothing. Here is what actually works.
This is the part that surprises people. A pressure washer moves water at high force, and oil does not dissolve in water. So when you hit an oil stain with pressure, you are just shoving the oil around the surface, not lifting it out of the concrete. Concrete is porous, like a hard sponge, and the oil has soaked down into those pores. Water skating across the top cannot reach it.
The fix is chemistry first, pressure second. You need a degreaser to break the oil down and pull it loose from the pores, and only then does the pressure washer flush the loosened oil away. Skip the degreaser and you waste your time. This is the same principle behind matching the method to the surface that we cover in soft wash versus power wash: the right chemical does the work, and pressure finishes it.
This is the workhorse method for most oil stains, fresh or moderately aged. Worked in order, it clears the large majority of stains.
Manufacturer dilution matters. Products like Simple Green are mixed a few ounces per gallon for normal soil and stronger for heavy grease, so read the label. According to cleaning references compiled by HomeGuide, the degreaser-plus-pressure combination is the standard professional approach for good reason.
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When a stain has been there for months or years, it has soaked deep, and a surface degreaser cannot reach all of it. This is where a poultice earns its keep. A poultice pulls oil back up out of the concrete rather than washing across the top.
Mix an absorbent material, baking soda, diatomaceous earth, or a fine clay, with a solvent or strong degreaser into a paste about the thickness of peanut butter. Spread it over the stain a quarter-inch thick, cover it with plastic taped at the edges, and leave it roughly 24 hours. As the paste dries, it draws the dissolved oil up into itself. Scrape it off, sweep it up, and rinse. Deep stains can need two or three rounds, and a hot-water rinse afterward cleans up whatever the poultice loosened. It is slow, but on an old stain that has resisted everything else, it is the method that works.
Set expectations honestly, because we do. A fresh spill cleaned promptly comes out almost completely. A stain that has lived on the slab for years may leave a faint shadow no matter how correct the process, because the oil migrated deep into the concrete and slightly changed its color. Cleaning still removes the vast majority and kills the greasy, slip-prone film.
The move after cleaning is to seal the concrete. A sealed slab does not let the next spill soak in, so future oil sits on top where it wipes or rinses off easily. On a driveway or a commercial lot that sees repeat spills, sealing is the difference between a five-minute cleanup and a permanent stain. It also protects against the road salt and freeze-thaw scaling that Michigan concrete fights every winter, which we cover in our guide to cleaning road salt off Michigan driveways.
For property managers, oil on concrete is not just cosmetic. A stained, greasy lot looks poorly run and creates a slip hazard, and drip stains multiply fast where fleets and delivery vehicles park. The right approach is scheduled cleaning, not waiting for stains to set. A lot cleaned on a regular cycle never lets oil soak deep, so each visit is faster and cheaper, the same logic we lay out for commercial parking lot pressure washing.
There is a compliance piece too. Oily wash water cannot legally run into a storm drain in most Metro Detroit municipalities. A professional crew captures and disposes of the wash water properly, which a hose-and-degreaser DIY job almost never does. That is a large part of what you are paying a commercial contractor for, along with the hot-water equipment and the right chemicals. The full parking-lot scope is on our parking lot cleaning page, and the broader case for a pro is in our why hire a pro guide.
Not on its own. Oil and water do not mix, so high-pressure water just pushes the oil around instead of dissolving it. The reliable method is a degreaser to break down the oil first, dwell time so it can work into the pores, then hot-water pressure washing to flush it out. Pressure is the finish, not the fix.
An industrial or citrus degreaser made for concrete works best. Common options include Simple Green Concrete and Driveway Cleaner, Krud Kutter, Zep Heavy-Duty Citrus, and Purple Power. Apply liberally, scrub it into the pores with a stiff brush, and let it dwell at least 5 to 30 minutes per the label before you rinse. Fresh spills also respond to cat litter or another absorbent first.
Use a poultice. Mix an absorbent material like baking soda or diatomaceous earth with a solvent into a peanut-butter-thick paste, spread it over the stain, cover it, and leave it about 24 hours. As it dries it pulls the oil up out of the concrete. Deep stains sometimes need two or three rounds, and hot-water pressure washing after.
After a degreaser has done the chemical work, a machine around 3,000 PSI with a 2.5 gallon-per-minute flow and a 15 or 25 degree nozzle lifts the loosened oil. Hot water helps a great deal because heat thins grease. A surface cleaner attachment gives even results on a large slab. Pressure alone at any rating will not dissolve oil.
Not always. Fresh spills come out almost completely. A stain that has sat for months or years soaks deep into porous concrete and may leave a shadow even after proper cleaning. Cleaning gets most of it, and sealing the concrete afterward makes future spills far easier to remove and keeps the surface from staining as deeply again.
On a schedule, not as emergencies. Regular commercial cleaning keeps oil from setting deep and keeps a lot presentable and slip-safe. A pro also captures and disposes of the wash water to stay within stormwater rules, which a hose-and-degreaser DIY job usually violates. For lots and garages, a recurring plan is cheaper and cleaner than one-off deep cleans.
PowerWashingExpert is a Metro Detroit commercial and residential cleaning company serving property managers, restaurant operators, homeowners, and facility leads across Oakland, Macomb, and Wayne counties. Our crews run hot water units, flat surface cleaners, soft-wash systems, and water reclamation equipment so every surface gets the right method and stays compliant with stormwater rules. Free quotes, written estimates, flat pricing. Call us at 248-254-6412 or request a quote online.