First few minutes
Just happened? Do this first
- Put on rubber or disposable gloves before you touch anything.
- Scrape off solids gently, without pushing them further in.
- Rinse with cold water, not hot.
- Wash your hands with soap and water afterward.
Poop stains on siding behave like protein stains, so cold water is the rule and heat is the thing to avoid. Fresh residue scraped off and rinsed cold usually responds to a mild dish soap scrub, while marks that have dried in may need a longer soak, which siding can take only with care. The material matters as much as the mark, since wood, vinyl and fiber cement each take a different level of scrubbing.
Rinse the area with cold water after each pass so soap doesn't dry on the siding and leave a film. If streaks show up after rinsing, they may be tannin bleed or rust, and those need their own fix instead of more scrubbing. If a mark survives a couple of rounds, test an oxygen bleach powder on a small patch, mixed as the label says.
Before you start
What siding, roof & exterior can take
Safe to use2
- Water
- Oxygen bleach
Use with care5
- Soaking
- Chlorine bleach
- Solvents (alcohol, spot removers)
- Acids (vinegar, lemon)
- Scrubbing and abrasives
7 items
What you'll need
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- Rubber or disposable glovesKeeps the mess and any germs off your hands. (opens Amazon)
- Garden hoseGives you the cold rinse and the final rinse.
- Mild dish detergentA gentle scrub in water that's safe on all siding types. (opens Amazon)
- Soft brush or clothSafe on wood, vinyl and fiber cement. (opens Amazon)
- Plastic drop clothProtects nearby plants from overspray. (opens Amazon)
- Oxygen-bleach deck cleanerFor mildew or organic growth on wood only. (opens Amazon)
- Oxalic-acid wood brightenerFor tannin bleed or rust streaks on wood only. (opens Amazon)
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5 steps
Step by step
Step 1 of 5
Gloves on, scrape, rinse cold
Pull on rubber or disposable gloves, then gently scrape away any solids without pushing them deeper into the siding. Rinse the spot with cold water from a garden hose, working from the edges toward the center so the stain doesn't spread.
Careful. Hot water cooks the protein and can set the stain, so keep the first rinse cold.
Step 2 of 5
Protect plants and test first
Sweep away leaves and debris, then cover nearby plants with a plastic drop cloth and spray them with water to dilute any overspray. Test any cleaner, and any pressure washer setting, on a hidden area before you work on the visible spot.
Step 3 of 5
Scrub with mild dish soap
Mix mild dish detergent in water and scrub with a soft brush on wood or vinyl, or with a soft brush or cloth on fiber cement. Work in small sections and rinse each one before you move on.
Careful. On fiber cement, a hard metal brush or abrasive sponge can damage the surface and finish.
Step 4 of 5About 15 minutes
Treat mildew with the right cleaner
If the stain is mildew or other organic growth on wood, apply an oxygen-bleach deck cleaner in sections and keep it wet for about 15 minutes. Then scrub along the grain. On fiber cement, use a mildew-specific cleaner with a soft cloth instead.
Careful. If the cleaner starts to dry before the 15 minutes are up, mist it with a hose rather than letting it sit dry.
Step 5 of 5
Rinse everything off thoroughly
Rinse the whole area with a garden hose, from the top down, until no soap or cleaner is left on the siding. Check the lower edges for runoff and rinse them too.
Careful. Cleaner or soap left to dry on the siding can leave its own marks.
If you'd rather buy than mix
Best products for poop on siding, roof & exterior
Look for an oxygen-bleach deck cleaner for wood, a mildew-specific cleaner for fiber cement, and an oxalic-acid wood brightener for tannin or rust streaks.
OxiClean Versatile Stain Remover Powder
How we picked these: each product is made for this type of stain, its maker doesn't warn against using it on siding, roof & exterior, and its directions fit the steps above.
Finished the steps? How does it look?
Nice work. Let it dry completely and check it again in good light. Here is what done looks like:
How to tell it's really gone →A faint mark usually needs one more round, not a stronger product.
If the stain was already dried or set, the method changes.
Old, dried or set-in stains →When to call a professional →How to tell it's working
The spot should look even in color, with no dark ring, shadow or greasy film left behind. Cleaned wood should look like its own color again, not patchy. If a faint shadow remains after several rounds, the stain may have set in, so move on to the set-in notes instead of scrubbing harder.
What changes for yours
Adjust for your siding, roof & exterior
Wood siding
Wood siding takes the full method, but pressure is where it goes wrong. Use the lowest pressure that cleans, and scrub or spray along the grain rather than across it.
The oxygen cleaner is for mildew only, so skip it if you only see dirt and soap residue. Old or dried stains on wood may need a second round, and the set-in notes cover that.
Fiber cement siding
Fiber cement can't take the same treatment as wood. Skip the high-pressure power washer, bleach and acid, because they can damage the surface and finish.
For mildew, use a mildew-specific cleaner on a soft cloth, as the mildew step explains. Rinse gently with a hose, since the goal is clean color, not force.
Vinyl siding
Vinyl siding needs gentler products than wood. Skip organic-solvent cleaners, undiluted chlorine bleach, liquid grease remover, nail polish remover and furniture polish, even when they seem to cut through the mess.
Never aim a pressure washer upward at vinyl; spray down along the panels instead. If the spot doesn't lift with the soap scrub and rinse, call a professional rather than trying a stronger cleaner.
Weathered gray wood
Gray wood that has lost its color can be restored with a commercial deck cleaner, brightener or restorer. These remove mildew and dirt so the wood's own color shows again.
If all the natural color has leached out, the wood stays silver when dry, and those fibers should be left alone. Old stain or sealer comes off with a stain and sealer remover, then gets neutralized with a brightener and lightly sanded once dry.
Tannin bleed or rust streaks
Reddish-brown tannin bleed and rust streaks from nails need an acid treatment, not a soap scrub. Use an oxalic-acid wood brightener exactly as its label directs.
Skip it on fiber cement siding, where acid is off limits. Rinse it fully afterward so no acid is left on the wood.
Old, dried or set-in stains
An old or dried stain on siding needs more rounds, not a harsher cleaner. Scrape off any crusted matter first, then go through the soap scrub again.
On wood, repeat the oxygen cleaner step in sections, keep the cleaner wet with a hose mist for the full 15 minutes, and rinse before the next round. On fiber cement, stick to the mildew-specific cleaner and a soft cloth.
A faint shadow can remain after several rounds, especially on weathered wood, and that's the realistic limit for this method. If the mark is still dark after that, a professional can take a look instead of you trying harsher products.
Vinegar, baking soda, peroxide and more
Do home remedies work on poop on siding, roof & exterior?
Most home remedies for this stain are for fabric, so only a few belong on siding. Mild dish soap and an oxygen cleaner handle this, and most other remedies are either unnecessary or too harsh for siding.
Works2Skip4
What makes it worse
Mistakes to avoid
Don't use steel wool or wire brushes.
Leftover iron in them reacts with the wood's natural extractives and leaves stains on exterior wood boards. A soft brush and mild dish soap do the job without that risk.
Don't scrub hard or power wash soft wood.
Caustic cleaners and aggressive scrubbing or power washing can strip the surface from soft woods like western redcedar. Keep the cleaning gentle and let the cleaner's dwell time do the work.
Don't use a narrow or rotating pressure tip.
Narrow-stream and rotating tornado tips are too aggressive for wood, so use a fan tip if you pressure wash at all. Keep the nozzle moving and the pressure low.
Don't mix cleaners without rinsing.
Oxalic acid neutralizes oxygen cleaners, so rinse the first product fully before you use the second. Give each product its own rinse rather than layering one over the other.
Don't wet-clean old CCA wood around kids and pets.
Wetting old CCA-treated wood raises the arsenic at the surface, and bleach releases chromate, so keep children and pets off it while it's wet. If you can't confirm whether the wood is CCA-treated, treat it as if it is.
When to call a professional
Call a pro if the stain stays after several rounds, since the stronger treatments aren't safe to try on siding yourself. For old lumber that may be CCA-treated, replacing it is safer than cutting or burning it, because the sawdust and smoke carry arsenic.
Questions
Can I pressure wash poop off siding?
Wood can take it at the lowest pressure that cleans, with a fan tip. Fiber cement shouldn't see a high-pressure power washer, and vinyl should never be sprayed upward, so start with the hose and soap scrub first.
Is bleach safe on poop-stained siding?
No, bleach isn't a safe pick for poop-stained siding. Fiber cement can't take bleach, and vinyl can't take it undiluted, so the mildew steps use an oxygen cleaner on wood or a mildew-specific cleaner on fiber cement instead.
Is poop on siding a health risk?
It can carry germs, so handle it as a health concern as well as a stain. Wear gloves while you scrape and rinse, and wash your hands with soap and water when you're done.
How long should the mildew cleaner stay on?
About 15 minutes on wood, and it should stay wet the whole time. Mist it with a hose if it starts to dry, then scrub along the grain before rinsing.
Can I use dish soap on fiber cement siding?
Yes, mild dish detergent in water is fine on fiber cement with a soft brush or cloth. Keep the scrub gentle and rinse the soap off well afterward.
Do I need an oxalic-acid brightener for every stain?
No, only for reddish-brown tannin bleed or rust streaks on wood. It isn't a general stain cleaner, and it stays off fiber cement entirely.
Poop on other materials
Other stains on siding, roof & exterior
Start from the bigger picture
How we know this
Every method, amount and warning here comes from university extension services, industry bodies and product makers. We read them, check every step for unsafe combinations and changed amounts, and write it up so you can follow it.