Cloth diapers function by combining an absorbent inner layer with a waterproof outer layer to contain urine and stool, working on the same basic principle as disposable diapers but using washable, reusable materials. The absorbent core soaks up liquid, a stay-dry layer pulls moisture away from the baby’s skin, and a waterproof shell prevents leaks onto clothing or bedding.
How the Layers Work Together
Every cloth diaper system has three functional jobs: absorb, wick, and contain. The absorbent core is typically made from natural fibers like cotton, hemp, or bamboo, layered or folded to increase how much liquid it can hold. On top of that core sits a stay-dry layer, often made from microfleece or suede cloth, that lets urine pass through to the absorbent material underneath but doesn’t hold moisture itself. This keeps the surface against your baby’s skin feeling relatively dry between changes.
The outermost layer is a waterproof shell that prevents liquid from soaking through to clothes or sheets. Most modern cloth diaper shells use a thin film of polyurethane bonded to a polyester fabric. Two versions of this material exist: TPU, which is heat-bonded, and PUL, which uses chemical solvents to create the bond. TPU is more breathable, allowing air to circulate through the diaper while still blocking liquid. That airflow helps reduce trapped moisture against the skin. PUL is also waterproof but slightly less breathable, and its manufacturing process involves solvents that raise environmental concerns.
Types of Cloth Diaper Systems
Cloth diapers come in several designs, each balancing convenience against cost and flexibility. The right choice depends on how much assembly you’re willing to do and how much you want to customize absorbency.
- All-in-ones (AIOs): The absorbent layers are sewn directly into the waterproof shell, so there’s nothing to fold, stuff, or snap together. You use it like a disposable, just fasten it on the baby. These are the easiest option for daycare providers or anyone who wants minimal fuss, but they take longer to dry since everything is one piece.
- Pockets: A waterproof shell with an opening where you slide in absorbent pads, called inserts. You can add more inserts for nighttime or heavy wetters and use fewer during the day. They need to be stuffed before use and unstuffed before washing, but that trade-off gives you the most control over absorbency.
- Prefolds with covers: Rectangular panels of layered cotton or cotton-blend fabric that you fold into thirds (or use a snappi fastener) and place inside a separate waterproof cover. This is the lowest-cost entry point. One cover can be reused across several diaper changes as long as it hasn’t been soiled, so you need roughly one cover for every three absorbent prefolds.
Skin Health Compared to Disposables
A common concern is that cloth diapers cause more diaper rash because they don’t contain the superabsorbent gel found in disposables. Research published in the Jornal de Pediatria compared rash rates between the two and found no significant difference. Mild rash occurred a few times a year in about 47% of both groups. Severe rash showed up in roughly 13% of disposable users and 11% of cloth users, a gap that wasn’t statistically meaningful.
Modern cloth diapers are designed to pull urine away from the skin through that stay-dry top layer, which functions similarly to the permeable liner inside a disposable. The key factor for preventing rash in either system is changing frequency. A cloth diaper left on too long will cause irritation the same way a disposable will. The difference is that cloth generally holds less total liquid before it feels wet, which can actually prompt more frequent changes.
How Washing Maintains Function
Cloth diapers only keep working properly if they’re washed correctly. When a baby urinates, the urine contains urea. Over time, especially in a warm, moist environment like a diaper pail, bacteria break urea down into ammonia. Ammonia buildup is what causes that sharp barnyard smell, and it can irritate skin and degrade fabric over time.
The standard approach is a two-cycle wash. A first cycle in warm water lifts surface-level soil and ammonia, flushing it away. A second heavy cycle in hot water deep cleans the fibers. Detergent choice matters too. Fragrance, fabric softeners, and optical brighteners are designed to leave residue on fabric after rinsing. That residue gives ammonia and bacteria something to cling to, making each subsequent wash less effective. A clean-rinsing detergent without those additives keeps the absorbent fibers clear and functioning at full capacity.
Cost Over Time
The financial function of cloth diapers becomes clear when you look at total costs over a year or more. Disposable diapers run roughly $800 to $1,300 per year when you include wipes and related supplies. A cloth diaper setup, including the initial purchase of diapers plus ongoing water, energy, and detergent costs for laundering, runs about $390 to $670 for the first year.
Because cloth diapers are reusable, the savings compound. The startup cost is front-loaded, but once you own the diapers, you’re only paying for laundry. If you use the same set for a second child, total savings over both children often exceed $1,000 to $2,000. Prefold-and-cover systems sit at the cheapest end of this range, while all-in-ones cost more upfront but still come in well below disposables over time.
Environmental Function
Cloth diapers reduce the volume of waste sent to landfills. A single child goes through an estimated 6,000 to 7,000 disposable diapers before potty training, and each one takes centuries to break down. Cloth diapers don’t eliminate environmental impact entirely since they require water, energy, and detergent for laundering. But the tradeoff shifts from solid waste to water and energy use, which many families consider preferable. Some newer shells made with TPU are marketed as biodegradable, though how quickly they actually break down depends on disposal conditions.