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Why are my cloth nappies leaking?

Not enough absorbency

Your baby may be outpeeing the inserts/absorbency you’re using in the nappy. Ideally we want to be changing cloth bums every 2-3 hours during the day, so if you’re changing every hour and the insert is soaking wet – it’s time to bump it up.

This is where nappy boosters come in and change the game. A booster such as a Little Lamb bamboo booster or a Thirsties hemp insert can increase the absorbency in your cloth nappies.

You can simply pair your booster with your current set up, but for the most effective boost you can fold up your booster and place it in your baby’s wet zone (the direct area they pee on). For boys it’s towards the front of the nappy and for girls it’s the middle.

Check out our chart to see which materials absorb liquid the fastest and which materials pair together best.

Before you splurge on boosters, you might have items in your stash that can double up as extra absorbency, for instance;

Flat nappies

Prefold nappies

Muslin squares


Poor fit

Cloth nappies at first glance look complicated with their multiple poppers and fastenings but there are a few basic checks you can do to ensure the fit is correct for a popper nappy:

1. Place baby’s bum down on the nappy, ensuring the top of the back of the nappy is in line with the hips (this is significantly lower than if you were using a disposable.)

2. Use your hand to then hold the middle of the nappy, squeezing it slightly it in your hands so that as you bring it up between baby’s legs, it fits neatly in the knicker line (note that some nappies such as certain Little Lovebum and Petit Lulu nappies, these can be resting on the thighs instead of in the knicker line)

3. Whilst holding the middle of the nappy in one hand, use your free hand to take one wing of the nappy, gently pulling it up and across and popping the hip popper first if you can. You want a snug fit without being tight (run your finger around the leg hole – if you can’t do this comfortably, it’s too tight.)

4. Popper the waist snap(s) – again these do not need to be too tight. Gapping at the top of the nappy is fine and normal and usually will not cause any leaks unless fabric is poking out.

5. Push your fingers up in between the rise poppers, pushing any excess fabric upwards.

6. Do your final checks and run your finger around the legs, making sure they are tucked into the knicker line comfortably and that no inserts, liners, or inner lining of the nappy are poking out and there aren’t any big gaps anywhere.

Important notes:

Symmetry is not necessary! You do not have to have the same amount of poppers on one side as the other. Focus on comfort and fit and not appearances.

For velcro fastened nappies follow the fit guidance above. If your baby is having any redness from the velcro rubbing on the tummy, try pointing the velcro downwards when you fasten instead of in line with the velcro.

Light sock marks (pink marks on skin) that fade by the next nappy change are normal! Red, painful looking marks/blisters are not – this is most likely caused by nappies that are too tight but can be due to the wash routine.


Tight clothing

If baby’s clothing is too tight around their cloth nappy, it may be pressing and squeezing pee out.

Don’t worry if your baby’s onesies are slightly too small – you can always buy a Little Lamb vest extender which poppers onto the onesie, making it bigger!


Problems within your wash routine

In some instances leaks can happen due to issues with your wash routine.

If there is a build up of detergent/nappy creams/fabric softener on cloth nappies they might not be absorbing as much liquid as they should be.

A good way to see if this is the root of your leak problems is to watch your washing machine when you’re doing your pre-rinse. Can you see suds? If yes, that’s a good indication that there is some detergent build up.

Ensure that you are using the correct amount of detergent for your machine/load/type of water – have a good read of the back of the detergent packet (who’s got time for Vogue magazine nowadays anyway?) and find out how much you should be using.

Remember you should be aiming for a ¾ full drum, so keep your detergent amount proportional to your wash load and avoid using fabric softener.

At the end of your next nappy wash, run an extra rinse cycle after your main wash cycle. Do this a few times. Then from your next nappy wash start implementing one extra rinse cycle after every main wash cycle and that should keep on top of detergent build up.

See our guide for an effective cloth nappy wash routine.


The nappy is damaged

Occasionally leaks can be due to old or damaged waterproof PUL fabric on the nappy.

If there are any obvious holes in the PUL then that’s probably the cause of your leak problem! But it’s quite unusual for PUL to be so damaged that it fails – unless it’s on a very old nappy which has been on direct heat quite a lot.

Old, slack elastics may be another cause of leaks. If when you stretch the leg elastics of the nappy and they don’t spring back as much as you’re used to, the elastics may need replacing – you can try replacing these yourself if you’re handy at sewing!

Unless you have a new faulty nappy, I’d expect damaged PUL or slack elastics on older, well used nappies such as preloved nappies.

Make sure when you purchase preloved nappies that the owner can send you detailed pictures of the PUL and leg elastics.


These are the most common reasons for leaky cloth nappies. If you've followed the guidance above and are still having issues, feel free to contact us via email at