TL;DR
Everything in a catio is a walking surface, so residue is the main risk rather than dirt. Sweep and scrape the debris out dry, wash shelves and mesh with plain soap and water, rinse until nothing is left behind, and let it dry fully before the cats return. Deep clean the whole enclosure two to four times a year.
Residue matters more than shine
Cats walk on every surface in a catio, then groom their paws. Anything you leave on a shelf ends up ingested.
That rules out concentrated disinfectants used without a rinse, scented outdoor cleaners, and any weed or pest product inside or around the structure. Some common garden treatments are dangerous to cats, and a catio floor collects overspray from anything applied nearby.
It also rules out essential oils. Many are toxic to cats, including tea tree, citrus, pine, and eucalyptus, and cats groom whatever transfers onto their fur from a surface.
The safe default is plain soap, water, and a thorough rinse, then time to dry. If something genuinely needs disinfecting, ask your veterinarian what to use and how long it needs to stay wet, and rinse it away completely afterward.
Source: ASPCA Animal Poison Control Center guidance on household and garden hazards for cats
What builds up in an outdoor enclosure
A catio collects a mix nothing indoors produces.
Leaf litter, pollen, seeds, and dust blow in through the mesh and pile in corners. Bird droppings land on the roof and drip through. Rain splashes soil onto lower shelves, and the whole structure grows a green algae film on the shaded side.
Then there is the cat contribution: fur, hairballs, the occasional accident, and food debris if you feed out there.
Damp wood is the structural issue. Shelves that stay wet grow mildew and eventually rot, and a rotten shelf is a fall risk.
How do you clean a catio?
Take the cats indoors, remove all bedding and bowls, then sweep or blow the loose debris out and scrape anything stuck. Wash shelves, ramps, and mesh with warm water and a small amount of plain soap, rinse everything thoroughly, and let the enclosure dry completely before the cats return.
The step-by-step routine
1. Bring the cats inside and shut the access door. Nobody should be in there while you work.
2. Remove everything loose. Beds, mats, bowls, toys, litter trays, and cushions come out and get washed separately.
3. Sweep and brush dry. Corners, shelf tops, and the floor. A stiff outdoor broom and a hand brush. Dry removal first means less mud later.
4. Scrape what is stuck. A plastic scraper for dried droppings and hardened debris. Bag it and put it in an outdoor bin.
5. Wash the shelves and ramps. Warm soapy water and a scrub brush. Work along the grain on wood, and pay attention to the front edge of each shelf where paws land.
6. Do the mesh and the frame. A brush along the wire clears pollen, cobwebs, and the algae film. Rinse it as you go.
7. Wash the floor. Sweep first, then wash and rinse. Take extra care with anything that becomes slippery when wet.
8. Rinse everything with plain water. Twice on shelves. This is the step that removes soap, and soap left on a walking surface ends up on paws.
9. Dry fully before letting cats back in. Open it up, let air and sun do the work, and give it several hours. Longer for wood in damp weather.
Wood, mesh and the algae film
Bare and stained wood. Soap, water, and a brush along the grain. Avoid soaking, and let it dry hard. Reseal or re-stain periodically with a pet-safe finish, applied when the cats are away and fully cured before they return. Follow the product instructions for cure time, since fumes matter here.
Painted and sealed surfaces. Wipe or wash easily. Watch for chips, since exposed wood absorbs water and rots.
Wire mesh. Brush it, rinse it, and check for rust or a gap. A hole in the mesh is the whole point of failure for an enclosure.
Plastic and composite decking. Washes easily, and it stays slippery with algae, so scrub the walking surfaces properly.
The green algae film. It is a damp-and-shade problem, not a dirt problem. Scrubbing with soapy water removes it, and improving airflow and light slows its return. Avoid strong algae-killing chemicals in a space cats walk on.
Bedding, bowls, litter and toys
Everything you removed at the start needs its own routine.
Wash fabric beds and mats on a cool cycle with unscented detergent, no fabric softener, and dry them fully before they go back out. Damp outdoor bedding grows mildew fast.
Bowls get washed daily if you feed outside, since outdoor food attracts insects and wildlife. Litter trays in a catio need the usual daily scoop and periodic wash.
Toys and scratchers get vacuumed and washed by their material. A sisal post outdoors weathers faster than one indoors, and the same rules apply as in how to clean a cat tree and scratching post.
For the full kit, our guide to cleaning pet bowls, bedding, toys and gear collects the same rinse-and-dry-fully approach.
Safety checks worth doing while you clean
A catio is a structure and it weathers, so cleaning day is inspection day.
Check every mesh panel for holes, rust, and gaps at the joints, and check that staples or fixings are still holding. Check that shelves and ramps are firmly attached and have not gone soft with rot, since a shelf that gives way drops a cat from height.
Check the roof drains and does not pool water, check the door latch closes properly, and check that no branch has grown into a position a cat could climb out on.
Look for wasp nests, spiders, and anything that has moved in. If you find a pest problem, an infestation, or evidence of rodents, that is pest control's job. A cleaning routine does not resolve an infestation and pretending otherwise wastes time.
How often should you clean a catio?
Sweep and spot clean weekly, wash the shelves and walking surfaces monthly, and do a full deep clean two to four times a year, ideally at the start and end of the wet season. In the Willamette Valley, where wet weather runs long, the shoulder months are the natural time for it.
Scoop any litter tray daily, wash bowls daily, and take bedding in when heavy rain is forecast.
A window perch is the indoor version of the same idea and gets cleaned on a similar rhythm, described in how to clean a cat window perch.
FAQ
What can you safely use to clean a catio?
Plain soap and water, followed by a thorough rinse and full drying. Cats walk on every surface and groom their paws, so residue is the main risk. Avoid essential oils, scented outdoor cleaners, and garden pest or weed products in or near the enclosure entirely.
How often should you clean a catio?
Sweep and spot clean weekly, wash the shelves and walking surfaces monthly, and do a full deep clean two to four times a year. Scoop any litter tray daily and wash outdoor bowls daily, since outdoor food attracts insects and wildlife quickly.
How do you get algae off catio shelves?
Scrub the surfaces with warm soapy water and a stiff brush, then rinse thoroughly with plain water. Algae is a damp-and-shade problem, so improving airflow and light slows its return. Avoid strong algae-killing chemicals on surfaces cats walk on and groom off their paws.
Can you use bleach in a catio?
It is a poor choice on walking surfaces, and it must never be mixed with ammonia, which is present in urine, or with vinegar or any acid, since those release chloramine and chlorine gas. If disinfecting is genuinely needed, ask your veterinarian and rinse thoroughly afterward.
How do you clean a wooden catio shelf?
Scrub along the grain with warm soapy water, rinse twice with plain water, and let the wood dry hard before the cats return. Avoid soaking it. Reseal or re-stain periodically with a pet-safe finish while the cats are away, and let it cure fully first.
What should you check while cleaning a catio?
Look for holes, rust, and gaps in the mesh, loose or rotting shelves and ramps, a door latch that no longer closes firmly, pooling water on the roof, and any branch a cat could use to climb out. Structural failures matter more than dirt.
An outdoor enclosure is one small piece of a much larger job. Every home is different, so the real number depends on size, condition, and what you want covered. Get a quote or read more about house cleaning services.