If you’ve noticed a strong, sour smell in your car that won’t go away, it could be rat urine. And once it’s there, it can be really hard to ignore. You might’ve cleaned the seats, sprayed air freshener, even left the windows open for days — but that musky, ammonia-like scent just keeps coming back.
The truth is, rat urine has a very distinct odour. It clings to surfaces and soaks into fabric, insulation, and plastic. It’s not just unpleasant — it’s also a sign that you might’ve had rats living in your car.
So what do you do now? This guide walks you through everything step by step — from identifying the smell to getting rid of it for good.
What does rat urine smell like?
Before you start scrubbing, it’s worth making sure you’re dealing with the right thing. Rat urine smells different from general bad car odour. It’s sharper. It has an ammonia-like scent that’s hard to miss once you notice it. Some people describe it as musty or sour. Others say it smells a bit like mouldy towels or stale old socks.
The smell is usually strongest in the mornings or after the car’s been closed up for a while. If you open the door and the odour hits you straight away, it’s a strong sign that something’s soaked into the fabric or air system.
You might also notice:
- Stains or spots near wiring, insulation, or under seats
- Chew marks or droppings nearby
- Nesting materials like paper or shredded plastic
If you’ve found any of these along with the smell, chances are a rat’s been living in the car.
Where should you check first?
Rats don’t usually leave mess in plain sight. They prefer warm, hidden areas where they feel safe. That means you’ll probably need to check places you wouldn’t normally look.
Start with these spots:
- Under the bonnet (especially near the battery or fuse box)
- Around the engine bay insulation
- Behind or under the dashboard
- Beneath the seats and floor mats
- Inside the boot, especially near the spare tyre
Use a torch if you need to. If you spot dark stains, damp patches, or shredded material in these areas, that’s where the smell is likely coming from.
Can rat urine make you sick?
Yes — in certain cases, it can. Rat urine can carry bacteria like leptospirosis, which can spread to humans through direct contact or inhaling particles from dried urine. That’s why it’s important to wear gloves and a mask when cleaning it up. You should also wash your hands thoroughly afterwards and avoid touching your face while cleaning.
If you’ve been feeling unwell with flu-like symptoms and think it could be connected to the smell in your car, speak to your GP as soon as possible.
How do you clean rat urine from a car?
Cleaning it properly takes more than a quick wipe-down. You’ll need to go deeper than that to remove the odour completely. Here’s how to go about it:
- Ventilate the car
Start by opening all the doors and windows. Let fresh air flow through for at least 15 to 30 minutes. This won’t remove the smell entirely, but it helps reduce the intensity and makes it easier to work inside.
- Remove any visible nesting material
If you spot shredded paper, bits of plastic, leaves, or cloth, remove it carefully. Use disposable gloves and double-bag everything before throwing it in the bin. Don’t vacuum this stuff — you don’t want to spread bacteria into the air.
- Clean up any droppings
Use paper towels and disinfectant to clean up droppings. Avoid brushing or disturbing them without protection. Always spray first to dampen them — that helps stop harmful particles from getting into the air.
- Locate and treat urine stains
Use a UV torch if you have one — rat urine often shows up under ultraviolet light. It usually glows a faint yellow or green, depending on the surface.
Once you’ve found the stain, spray it with an enzymatic cleaner made for urine odours. These cleaners break down the proteins in the urine that cause the smell. Don’t just wipe it straight away — let it soak in for 10 to 15 minutes first. Then scrub gently with a soft brush or microfibre cloth.
Repeat the process if the smell’s still strong.
What’s the best cleaner for rat urine in a car?
Standard car cleaning sprays often don’t work on rat urine. You’ll need something made for biological mess — like pet urine cleaners. These are enzyme-based and are designed to target organic odours, not just cover them up.
Look for products that say they remove:
- Urine odours
- Protein-based stains
- Pet or rodent smells
Brands like Simple Solution, Nature’s Miracle, or Urine Off are often recommended. Make sure the product is safe for use on upholstery, plastics, and carpets. Always test a small area first, just to be safe.
Can vinegar or baking soda remove the smell?
Vinegar can help neutralise some of the ammonia smell, but it won’t break down the urine itself. Same with baking soda — it might absorb some of the odour, but it won’t clean the area deeply enough.
That said, if you don’t have an enzyme cleaner to hand, you could try this short-term:
- Mix equal parts white vinegar and water in a spray bottle.
- Spray the affected area lightly — don’t soak it.
- Leave it for 10 minutes, then blot dry.
- Sprinkle a small amount of baking soda over the area.
- Leave it overnight, then vacuum it up.
This might reduce the smell, but you’ll still need a proper cleaner to deal with it long-term.
What if the smell’s in the air vents?
Rats sometimes nest behind the dashboard or near the cabin air filter. If the smell comes through the vents when you turn on the heater or air con, it’s likely the filter’s been contaminated.
Here’s what to do:
- Remove and replace the cabin air filter (you can usually find this behind the glovebox)
- Spray an enzyme cleaner into the air intake vents
- Let it sit for 15 minutes before running the fans on full blast
- Repeat as needed until the smell clears
If the smell is really strong, you might need a professional to take the dashboard apart and clean the inside properly.
Can a car valeting service remove rat smell?
Some valeting services offer deep-cleaning options that go beyond a standard wash. Look for one that provides:
- Interior sanitising
- Odour elimination
- Upholstery shampooing
- Air system treatment
Call ahead and explain what you’re dealing with. Not every valeter will take on rodent-related jobs, but many will — especially if they work with taxis, commercial vehicles, or rental cars.
This is a good option if the smell is lingering and you’ve already tried cleaning it yourself.
How long does it take for rat urine smell to go away?
It depends on how deep the urine soaked in, how quickly you treated it, and how thorough the cleaning was. If it’s on the surface and you deal with it straight away, you might notice a big improvement within a few days.
But if it’s in the carpet padding, under seats, or inside the dashboard, it can take weeks to fully go. That’s why enzyme cleaners and repeat applications are often needed. Patience is key here.
How can you stop it from happening again?
Once you’ve cleaned everything, you’ll want to make sure rats don’t come back. Prevention is just as important as cleaning.
Here’s what you can do:
- Don’t leave food or wrappers in the car, even for a day
- Park in open, well-lit spaces whenever possible
- Keep the area around your car tidy — no bin bags or stacked boxes nearby
- Leave the bonnet slightly open when parked at home (if safe)
- Use peppermint oil or rat deterrent sprays near the engine bay
If you’ve had a rat in the car once, it’s more likely to happen again — unless you change the environment that made it comfortable for them in the first place.
Final thoughts: Clean it properly, then keep it clean
Rat urine in your car isn’t just a bad smell. It’s a warning sign. It means your car was home to a rodent, even if just for a night. That smell won’t go away on its own, and the longer it stays, the harder it is to shift.
But you can sort it. It takes patience and the right cleaner, but you can absolutely get rid of the smell — and stop it coming back.
Take your time, work through it step by step, and don’t rush the process. Once it’s clean, you’ll feel better every time you open the door.
