Tea towel testing (and why your PUL probably isn't problematic) - Baba+Boo

Tea towel testing (and why your PUL probably isn't problematic)

Failed PUL. It’s everywhere right now. Faulty pre-loved nappies are being sold left, right and centre; new nappies are only lasting a month or two; and nappy libraries are being inundated with useless nappies that are good for nothing except making bunting.

Clearly, there’s a problem. But the problem isn’t the nappies. All these reusables with “failed PUL”? They’re fine. They’re usable, good quality nappies with many months and years of wear left in them. 

Last week there was a message from a beleaguered nappy librarian who was trying to track down a parent who had sent her some failed nappies to use for bunting.

The nappies in question were two nearly new, expensive nappies that had failed ‘the tea towel test’.

But the librarian - who has been inundated with ‘failed PUL’ in recent weeks - decided to check the PUL herself. And, like so many nappies that she’s been sent recently, the PUL was absolutely fine. The chances are these nappies have enough wear in them to last another two or three children. 

So what’s going on to make perfectly rational people assume their nappies are rubbish?

To start at the beginning, ‘PUL’ is simply the layer inside a pocket (or wrap) that makes the nappy waterproof. 

If you’ve been around cloth nappies long enough you’ll have noticed the trends and cycles that come and go. And right now, the tea towel test is on people’s minds. 

A search of a popular online nappy group reveals no mentions of the tea towel test in the whole of 2018. In the last three months? Twenty six. And in another group - three mentions in 2018; 24 in the last three months.

The tea towel test has been around for a long time. It’s a useful, niche solution for a specific problem. You wet and fold one tea towel and place it in the nappy in question, then lie a dry one underneath. If the one underneath is wet after 30 minutes, you might have a problem with the PUL>

But it was never intended as a catch-all, go-to remedy for leaks.

And the implications for the way it’s now being used and recommended are worrying.

Why not-so-dodgy PUL matters

Firstly, the number of nappies ‘failing’ the tea towel test is significant. As happened with the nappy librarian’s experience, it means that perfectly good nappies are being chucked away. By the bucket load. It’s an eye-watering waste of money - and our planet’s resources.

Secondly, it implies that failed PUL is a big issue. Those of us who have been around nappies for a long time know that failed PUL in good quality nappies is not common.

But look online at the moment and it would be easy to conclude that it’s totally normal for PUL to fail within a few months. If we want reusable nappies to become mainstream, we cannot create a myth these products are of such poor quality that they fail so quickly. 

Thirdly, when parents ask for advice online, it’s unhelpful to suggest PUL is the issue. If a parent is having leaks, it’s unlikely that failed PUL is the cause. Leaks are almost always due to fit or absorbency. Leading new, daunted parents down the rabbit hole of dodgy nappies overwhelms them - and it prevents them from solving the real problem.

Why do so many nappies fail the tea towel test?

There’s nothing wrong with the tea towel test - but doing it correctly is not as straightforward as people assume, especially with pockets. (It’s worth noting that the original article about the tea towel test refers to wraps, not pockets.)

If you understand how PUL works, and you follow the instructions carefully, the tea towel test might just help you out if you’re at a loss as to why a nappy isn’t working for you. 

PUL is waterproof - sort of. But if you’ve ever left a reusable nappy on for too long then you know that, eventually, it will leak. The fluid will make its way through the weakest spot - which is usually the stitching around the legs.

That’s what’s happening with the tea towel test. The liquid from the test is wicking through the stitching. That’s natural, it’s normal, and just the way PUL works. It doesn’t mean your nappy is going to leak (unless you leave it on for too long…) and it doesn’t mean the PUL has failed.

How should I check PUL?

The best way to check PUL is also the simplest: visually. The vast majority of PUL damage/wear can be seen - if it’s there you’ll know it.

Having said that, if you do see ‘damage’ - little cracks or irregularities - the beauty of PUL means the nappy could continue to function for many more months or years. Even with small snags, the PUL will only leak if the inserts are saturated enough that the fluid goes for an escape route. 

When should I check the PUL?

Having leaks does not mean it’s time to reach for the tea towel. If you’re online and someone is having leaks, then please, please, please do not reply with the words “Have you tried the tea towel test?”

If you’re worried for yourself then our PUL checklist should help.

The dodgy PUL checklist

-Testing PUL is a last resort, not a first port of call.

-If you’re having leaks then the most likely cause is fit or absorbency.

-If you’re having leaks from more than one nappy then it is unlikely to be PUL (assuming you’ve followed your manufacturer’s guidelines). 

-If it is always the same nappy that leaks then check the elastics and give the PUL a visual inspection. 

-A visual check of PUL is usually all that’s needed - it’s probably around 1 in 50 PUL issues that aren’t immediately visible.

-If the elastics and PUL appear to be in tact you may wish to do a PUL test using the bucket method or the tea towel test; ensure you follow the instructions carefully.

-If the nappy fails around the stitching then it's probably an incorrect test, not a failed nappy.

-Cracks and marks do not automatically mean the nappy will not work for you. Depending on how quickly the inserts get saturated, you may find that the PUL remains ‘good enough’.

-If you have bought a pre-loved nappy and want to check it meets the seller’s description, then you may wish to give it a visual check before using it. If it passes a visual check, there is little reason to do a tea towel test - remember, it’s a test of last resort, not a first port of call.

-“I’ve washed my nappies at 90 - will they survive?” is a question we see fairly often. The answer is probably/maybe/possibly. The easiest way to find out if they’ll survive isn’t to individually test all your nappies - it’s to put them on your baby and see what happens.

-If you have more than one pocket with a problem then it’s likely that something is damaging your nappies - eg rings or nails during stuffing, an over-enthusiastic washing machine, or excess heat. 

-Eventually PUL will degrade - but as long as your nappies are well cared for that takes a long time. 

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This is really useful. I have 2 B&B I bought second hand and at least one of them has leaked on two occasions (they’re similar prints so I can’t recall if its the same one each time). I had been going to do the tea towel test before using them again but I think I’ll brave putting them on the baby again to see what happens! One question – you mention the bucket test – what’s this?


Such great advice! Thank you!

Melody Blundy

That’s a helpful article thank you! However I’m getting leaks with all my nappies – I’ve tried bamboo, hemp, and charcoal inserts. I’ve tried putting a bit of cotton on top of the hemp, tried pairing the charcoal with the bamboo, tried one insert, two inserts, three inserts and we still get loads of leaks sometimes after an hour. I have some nappies that last nearly 3 hrs but all my pockets need to be changed after about 1.5 hrs max. That’s a lot of nappy changes in a day and prob wouldn’t help us get this to be “mainstream” (when we use single use nappies on holidays I’m amazed at how few nappy changes we need to do! ) Any tips?! :)


This is such a useful read. We have been using cloth for 2.5 years and never had any PUL issues


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