How to Remove Feces from Concrete
Always test on a hidden area first. Never mix cleaning chemicals — bleach and ammonia, or bleach and acids (including many bathroom/vinegar-based cleaners), release toxic gas. Follow the product label on every cleaner you use.
Before you start
- Check whether the concrete is plain, sealed, or decorative before using any acid-based product — sealed and decorative finishes are vulnerable to etching even though plain concrete tolerates acid reasonably well.
- Don't let this sit for an extended period on unsealed concrete; the surface is porous enough to develop a genuinely permanent stain given enough time.
At a Glance
- Difficulty
- Moderate
- Primary method
- Scrape, enzyme cleaner, check for sealant before using acid-based products
- Water temperature
- Cool
- Machine washable?
- No
- Success outlook
- Good on plain concrete; more limited on sealed or decorative concrete
What You'll Need
- Disposable gloves
- A plastic scraper
- An enzyme-based concrete cleaner
- A stiff outdoor brush
- A hose or bucket for rinsing
- A concrete-safe disinfectant
Step-by-Step
- Wearing gloves, scrape up solid material, working it away from the surface rather than grinding it in.
- Apply an enzyme-based cleaner suited for concrete and let it sit to work into the porous surface.
- Scrub with a stiff outdoor brush, focusing on working the cleaner into the pores rather than just across the top.
- Rinse thoroughly with a hose or bucket of water, since concrete needs a genuine rinse rather than a light wipe.
- Once dry, apply a concrete-safe disinfectant, checking first whether the surface is plain, sealed, or decorative, since that changes which products are appropriate.
Cold Water vs Hot Water
Cool water is fine throughout for plain concrete, which is durable and not particularly heat-sensitive. The real distinction on this surface isn't temperature but whether the concrete is sealed or decorative — that status matters more here than water temperature does.
If the Stain Has Already Dried or Set In
Plain, unsealed concrete is genuinely porous and can absorb both moisture and staining if this sits for an extended period, which means an old or dried accident often leaves a permanent shadow even after thorough cleaning, similar to an oil stain on a driveway. Repeated enzyme treatments help, but full removal of a truly set-in stain on porous concrete isn't always achievable, and that's worth knowing before investing significant effort in it.
What Not to Do on This Surface
Don't use a strong acid-based cleaner on decorative, stained, or sealed concrete without checking compatibility first — acid etching is a real risk on any concrete with a decorative finish or sealant, even though plain structural concrete generally tolerates it better. Don't let this sit on porous, unsealed concrete for an extended period if you can help it, since that's when a treatable surface stain becomes a genuinely permanent one.
When to Call a Professional
A professional pressure-washing or concrete restoration service is worth considering for a large accident, a stain that's already set into porous concrete, or any decorative or stained concrete surface where you're not confident which products are safe. For a small, promptly caught accident on plain garage or patio concrete, home treatment with an enzyme cleaner is usually sufficient.
The Full Picture
Concrete's porosity is the defining fact for this pairing, and it cuts both ways: plain concrete tolerates a fairly aggressive scrub-and-rinse approach that would be too harsh for natural stone, but that same porosity means a stain given real time to sit can genuinely penetrate deep enough to leave a permanent mark, the same way an old oil stain lingers on a driveway.
Unlike natural stone, plain structural concrete generally tolerates acid-based cleaners reasonably well, which opens up more product options here than on marble or limestone — but that changes the moment the concrete is decorative, stained, or sealed, since those finishes carry their own acid-etching vulnerability independent of the plain material underneath.
Speed genuinely decides the outcome on porous concrete more than which product you reach for — a fresh accident cleaned within a reasonable window comes out well, while the same accident left for days becomes a much harder, sometimes unwinnable, cleaning project.
Outdoor concrete surfaces also deal with this stain reasonably often given pets and wildlife, which is part of why an enzyme-based outdoor concrete cleaner, rather than a generic household product, is the more practical default tool for this specific surface.
Frequently Asked Questions
- Is it safe to use bleach on outdoor concrete for this?
- On plain, unsealed structural concrete, generally yes, in a diluted form. On decorative, stained, or sealed concrete, check the sealant manufacturer's guidance first, since bleach and other harsh chemicals can affect certain sealants and decorative finishes.
- Why did this leave a permanent mark on my concrete even though I cleaned it?
- Unsealed concrete is porous, and if the stain had time to sit before you addressed it, some of it can penetrate below the surface where cleaning can't fully reach — similar to how an old oil stain lingers on a garage floor. Prompt treatment is the best prevention for this outcome.
- Does sealing my concrete afterward help prevent this in the future?
- Yes — a concrete sealant reduces porosity and makes future accidents in the same area much easier to clean fully, since there's less opportunity for staining to penetrate below the surface.
Surface caution: acid etching on decorative/sealed concrete; prolonged staining once it penetrates the pores.