Leak-free Cloth Diapering Systems Since 1991!

Cloth diapering 101: “Why do my cloth diapers leak?”

One of the most common questions we find on various online forums is “why do my diapers leak?” Parents are looking for guidance and advice from fellow parents. Most of the well-intentioned advice says “add another liner/insert for more absorbency” or “you must have build-up and therefore water repellency issues.” This could be true, but there is a more prominent reason why diapers and diaper covers fail.

The problem is usually with the diaper cover itself. The cover has two components that make it function leak-free: one is the Thermoplastic Polyurethane film laminated to the back side of the fabric. This film creates a water proof barrier and prevents moisture from seeping through the cover fabric. So long as this film is intact and not peeling, this is not the problem.

The other component — equally as important — is the Water Repellent applied to the face side of the fabric. You can’t see or feel it. No one knows it’s there.

Intact Water Repellent

Here is a short video demonstrating water beading up on fabric with a functioning water repellent:

The water repellent’s job is to prevent moisture from being drawn (wicking) from the absorbent component (diaper itself) through to the outside (face side) of the cover through the stitching on the diaper or cover. This water repellent must be intact for the cover to be effective. Water repellents have a limited longevity and can vary significantly from brand to brand. Once a diaper cover – whether attached to the diaper (Pocket, All in One) or worn over top (pre-folds, fitted diapering systems or Hybrid/All in Two) – shows signs of leakage, an evaluation should be made as to whether the repellent is still effective.

If you are experiencing unexplainable leakage, here is a simple at-home test. Flick some tap water onto the fabric surface (face side). If it beads up, your water repellent is intact. If it sits there for a moment and slowly absorbs, your water repellent is marginal, and if the droplet is absorbed upon immediate contact, the water repellent has expired. Leakage will be a regular occurrence. At this point, you can add numerous layers of absorbency to your diapering system, but the diaper will still leak.

Pocket Diaper Leak Test

We tested this pocket diaper by placing water with food coloring on the inside. As you can see, the color traveled to the face side. The water repellent is no longer working. Moisture will travel through the stitching to the face side of the cover and is transferred onto clothing and bedding. 36 launderings ago this cover’s water repellent beaded up as pictured above and would have prevented the moisture from wicking.

It’s not the water repellent. What else can I try?

If the film and water repellent are intact and you are still experiencing leakage, we now look further to see where the problem may lie. This is somewhat hard to describe so bear with us and read thoroughly.

When the cover and absorbent component of a pocket diaper or all-in-one diaper are cut to the same size (as with most diapers on the market), the addition of liners/inserts to the pocket diaper will make the diaper as a whole, slightly convex.Convex pocket diaper

Through laundering, calcium and magnesium deposits can “plate up” on fibre surfaces and residues from diaper rash creams cause fabric surfaces to become slightly repellent. As a result, liquid takes a moment to penetrate the fabric. If the surface is convex, the liquid may roll off before it has time to penetrate. For more optimal performance, a diaper needs to be slightly concave in order to better hold the liquid.

In order for new parents to better understand their diapering options a guide to cloth diapering has been added to our site. It lists the pros and cons of the various diaper systems available on the market.

So, as you will have learned from this post if your cover is leaking because the water repellent has stopped working, there is no solution other than to replace your diaper or diaper cover. If your diaper or cover passes the flick test, there is a possibility that your problem may lie within the composition of the diaper itself. We hope you find this information helpful.

Erika Froese

Join our newsletter to receive cloth diapering support straight to your inbox:



One Response to “Cloth diapering 101: “Why do my cloth diapers leak?”

  • Elizabeth
    1 year ago

    I had remembered reading this when it was posted and thought … OH wow…file that in the back of my head. Well it came time to trouble shoot and did the test! Sure enough! waterproof outer was gone! WHO KNEW! have posted a video of my test to my local cloth diaper support group with a link to you Blog….. Way to go ME for educating the masses!

Leave a Reply

Your email address will not be published. Required fields are marked *