Does Your Rain Jacket Smell Bad?

You grabbed your used rain jacket from the closet and got hit with a strong ammonia smell. 

It's not mildew. It's not body odor. It's something sharper, almost like cat pee or cleaning chemicals. 

You're wondering if the jacket is ruined, if it's safe to wear, and what the hell happened to it while it was just sitting there. Here's what's actually going on with your jacket.

What's Making Your Jacket Smell Like Ammonia?

The smell comes from polyurethane coating breakdown. Most waterproof rain jackets have a thin layer of polyurethane (PU) on the inside that keeps water out. Over time, this coating degrades through a process called hydrolysis. 

When the polyurethane breaks down, it releases organic compounds that smell exactly like ammonia.

Hydrolysis happens when moisture reacts with the polyurethane coating. Even if you stored your jacket in what you thought was a dry place, humidity in the air is enough to start the process.

The coating literally falls apart at a molecular level, and those broken-down chemicals create that distinctive sharp smell.

A 2018 study in the Journal of Applied Polymer Science found that PU coatings can begin degrading within 3-5 years depending on storage conditions and jacket quality. 

Cheaper jackets with thinner coatings break down faster. But even expensive jackets aren't immune—they just take longer to deteriorate.

Heat speeds up the breakdown. If you stored your jacket in a hot attic or garage, you basically created the perfect conditions for the coating to fall apart. The combination of heat and moisture is what really destroys these coatings.

Can You Still Wear a Jacket That Smells Like Ammonia?

Short answer: yes, it's safe to wear, but it probably won't work as a rain jacket anymore.

The ammonia smell itself isn't toxic in the amounts you'd encounter from a jacket. The compounds causing the odor are irritating but not dangerous unless you're literally huffing the jacket (which you obviously shouldn't do). 

You might notice some skin irritation if you wear it for extended periods, especially if you sweat, but most people won't have any reaction.

The bigger problem is that the jacket has lost its waterproofing. When the PU coating breaks down, it stops being waterproof. 

You might notice a sticky or tacky feeling on the inside of the jacket. Sometimes the coating flakes off in pieces. If you wear it in the rain, water will soak right through.

Some people report that the smell fades after the jacket airs out, but the waterproofing issue doesn't fix itself. You're basically left with a breathable shell that won't keep you dry.

Symptom	What It Means	Can You Fix It?
Strong ammonia smell	PU coating is breaking down	No, the damage is permanent
Sticky/tacky interior	Coating is degrading	No, it will continue to worsen
Coating flaking off	Advanced hydrolysis	No, coating needs replacement
Lost waterproofing	Coating no longer functional	Sometimes, with recoating

How Do You Get Rid of the Smell?

You have a few options, but none of them are perfect.

Washing the jacket might help temporarily. Use cold water and a gentle detergent made for technical fabrics. Don't use regular laundry detergent—it can make the problem worse. Hang it to dry completely. Some people report the smell comes back after a few days, while others say washing helped significantly.

Stripping the old coating is the nuclear option. You can remove what's left of the degraded PU coating using isopropyl alcohol or specialized coating removers. This is tedious work—you basically scrub the inside of the jacket until all the old coating is gone. It takes hours and makes a mess. But once the old coating is removed, the smell goes away completely.

After stripping the coating, you can apply a new waterproof treatment. Products like seam sealers or brush-on waterproofing can restore some water resistance.

But you're never going to get back to original factory waterproofing. The new coating won't last as long and won't perform as well.

Airing out the jacket in direct sunlight for several days helps some people. UV light can break down some of the smelly compounds. But this doesn't fix the underlying coating failure—it just masks the smell temporarily.

Some people throw the jacket in the freezer for a few days. The cold slows down the chemical reactions and can reduce the smell. Again, this is temporary. The smell usually comes back once the jacket warms up.

What About That Used Rain Jacket You Just Bought?

If you bought a used rain jacket online or from a thrift store and it arrived smelling like ammonia, you got a jacket with a failed coating.

This is common with older outdoor gear. The previous owner probably didn't mention it because they didn't know about the problem, or they were hoping you wouldn't notice until it was too late to return it.

Check the inside of the jacket. If it feels sticky or you can see the coating peeling, the damage is already done.

You can try the cleaning methods mentioned above, but be realistic about your expectations.

A jacket with advanced hydrolysis isn't going to become fully waterproof again without professional recoating, which typically costs more than buying a new jacket.

Some outdoor gear companies offer recoating services. You send them your jacket, they strip the old coating and apply a new one.

Prices range from $40 to $100 depending on the jacket size and complexity. Whether that's worth it depends on how much you like the jacket and how much you paid for it.

How Can You Prevent This From Happening?

If you want your current rain jacket to last longer, store it properly. Keep it in a cool, dry place with good air circulation. Don't leave it stuffed in a compression sack or storage bag—the jacket needs to breathe.

Hang it on a hanger in a closet, not in a basement or attic where temperature and humidity fluctuate. Clean and dry the jacket completely before storing it for the season. Trapped moisture and body oils accelerate the coating breakdown.

Some people recommend storing jackets with desiccant packets to absorb moisture. This probably helps, but it's not a guarantee. Even with perfect storage, PU coatings eventually fail. It's just a matter of when, not if.

Newer jackets use different waterproofing technologies that don't have the same degradation issues.

Jackets with ePTFE membranes (like expanded polytetrafluoroethylene) or newer polyester-based coatings last longer and don't develop the ammonia smell.

If you're buying a new jacket and plan to keep it for years, look for these technologies instead of traditional PU coatings.

So What Should You Do With a Smelly Jacket?

If the smell bothers you and the jacket isn't waterproof anymore, you have three real choices. One, strip the coating and reapply a new treatment if you're handy and have time. Two, pay for professional recoating if the jacket is worth saving.

Three, accept that the jacket has reached the end of its waterproof life and replace it.

For most people, option three makes the most sense. Technical outdoor gear has a lifespan, and PU-coated rain jackets typically last 5-10 years before the coating fails.

That ammonia smell is basically your jacket telling you it's time to retire it.

You can still use it as a light windbreaker on dry days. Just don't expect it to keep you dry in the rain.

And if the smell is really strong or you notice skin irritation, it's probably time to let it go. Your rain jacket served its purpose, but the chemistry of its waterproof coating has finally caught up with it.

Frequently Asked Questions

Why does my rain jacket smell like ammonia or cat pee?

Answer: That sharp ammonia smell comes from the polyurethane (PU) coating breaking down through a process called hydrolysis. Moisture and heat cause the waterproof coating to decompose, releasing compounds that smell like ammonia.

Is it safe to wear a rain jacket that smells like ammonia?

Answer: Yes, it’s generally safe to wear, but it’s no longer waterproof. The smell isn’t toxic in small amounts, though it may irritate sensitive skin. The real issue is the failed coating—it won’t keep you dry anymore.

Can I remove the ammonia smell from my jacket?

Answer: You can lessen the smell by washing the jacket gently with a technical fabric cleaner or airing it out in sunlight. For a permanent fix, you’d need to strip the degraded coating—a time-consuming process that removes the smell but won’t fully restore waterproofing.

Can a jacket with a broken PU coating be repaired?

Answer: Partially. You can try professional recoating services or apply DIY waterproofing treatments, but these won’t bring it back to factory quality. Often, it’s better to replace the jacket if the coating is sticky or flaking.

How can I prevent my rain jacket from developing this smell?

Answer: Store it in a cool, dry place, not a hot attic or damp basement. Always hang it loosely, make sure it’s completely dry before storage, and avoid compressing it for long periods. Proper storage can delay hydrolysis for years.