Laundry Science

Laundry Science

Evidence-based cloth diaper washing
WATCH formula

Best Available Information
 We know that there are a lot of opinions on cloth diaper laundry, and people find their own way of doing things. We looked for personal experience during the 100% campaign and got a lot of feedback.
 We realized, though, that we need to understand the science of laundry, so we can all be confident that we give new parents the best possible chance to succeed with cloth diapers.
 RDA's Cloth Diaper Laundering Instructions represent the best available knowledge in the cloth diaper industry.

The WATCH Formula
 Five factors work together in laundry.
 Water – Water does a good portion of your cleaning. You may need to make adjustments to make up for poor water quality. Water plays a large role in cleaning cotton and hemp.
 Agitation – Mechanical action (rubbing together in a top loader, "the fall" in a front loader) simulates hand scrubbing.
 Time – Length of cycles (and/or soaking) affects cleaning.
 Chemicals – (Clean rinsing) detergent is especially necessary in cleaning artificial materials, which are oil-loving and bond with the oils and fats in human waste.
 Heat – While most home laundry machines can’t get water hot enough for long enough to kill organisms, higher heat helps the other components do their parts.

Note that if you reduce one factor in the formula (reducing heat by washing in cold water, for example), you need to increase the other factors to clean your diapers successfully.

WATCH formula adjustments

Dump solid material into toilet.
Exclusively breastfed baby waste is water soluble so will be removed in the initial rinse cycle. Solid- or formula-fed baby waste should be dumped first.

Put diapers in (dry) pail until wash time.
It’s safer not to leave a wet pail around the home with toddlers. That said, if you’re okay with the safety issue, it doesn’t hurt to soak, it’s just not necessary if all else is working okay with your process.
Optimally run your load once you can mostly fill, but not overstuff, your washer.
Most people have success washing every 2 or 3 days, washing 12-24 diapers at a time.

It depends, though, on the size of your washer. Too full a load is not good (inadequate access to water and detergent); too empty a load not good (too much space prevents sufficient agitation).
Rinse diapers in warm water.
Soil is most easily removed at the temperature it was added at. Waste comes out at approximately body temperature, which is approximately what temperature "warm" water is in a washing machine.
Detergent should be fragrance- and color-free with no optical brighteners or fabric softeners.
You’re looking for a detergent that is clean-rinsing and won’t leave any residues on your diapers. You also want it to be safe for your baby’s skin.
Use additional detergent if you have hard water.
Just as shampoo goes further in soft water than hard, so you should adjust the amount of laundry detergent depending on your water quality.
Use enough detergent to clean a load of dirty laundry, but not too much.
Because some laundry detergents are not clean-rinsing, people often recommend reducing the amount of detergent for diapers. However, the most common cause of diaper stink is actually that they’re not getting clean enough --- not detergent buildup.
Rinse twice in warm water.
Most wash cycles will end with a rinse, so you can set the machine for an extra rinse.

This increases the amount of water, which is particularly useful in cleaning natural fibers like cotton and hemp.

It will also be sure to rinse out any remaining detergent to prevent buildup.
Rinse twice in warm water.
Warm water will release residues more effectively and will release more water from the fabric in the spin cycle, shortening drying time.
Thoroughly dry diapers in the sun or in your automatic dryer.
The sun will save energy and bleach out stains. It also will prolong the life of the fabric.
Thoroughly dry diapers in the sun or in your automatic dryer.
If you use a dryer, use the lowest temperature that successfully dries your diapers. Drying at high temps reduces the life of any fabric or component.
Additional Recommendations
 RDA cloth diaper washing instructions assume a mixture of fabric types. For better results, separate fabrics.
  Use more water to clean (hydrophilic) cotton and hemp.
  Use adequate detergent with manufactured (oliophilic) fibersto break the bonds with oil/fat waste, but still be sure to rinse thoroughly.
  Bamboo (rayon) cleans best in neutral pH levels. Though water quality plays a role here, using liquid detergents might help.
 If you are having trouble with your diapers, consult the manufacturer.

 It’s important to all of us at RDA that we distribute science-based information, so we consulted with scientists and others from the industry who have knowledge of laundry.
 Thanks go to the following people for their contributions to these recommendations:
  Clark Caswell, Mt. Hood Solutions
Steve Tinker, American Reusable Textiles Association, has 40 years of experience in the laundry chemical industry, including more than 20 years in R&D. He has a bachelor's degree in Chemistry from the University of Minnesota.
Shirley Murdock, Bummis, has a university degree in biochemistry, which she has put to use in research, testing, and laundry support during her 14+ years in the cloth diaper industry.
Marc Pehkonen, Firefly Diapers, has a bachelor's degree in Materials Science from the University of Bath, England. He has worked in polymer research for BP and Saint Gobain Corporation and is currently a lab supervisor for BioFire Diagnostics, a biotechnology company based in Salt Lake City, Utah. He has been involved in a technical capacity with Fuzbaby and Firefly Diapers since 2000. 
Kim Webb, Rockin’ Green
Do you have specific questions that aren't answered in the Basic Cloth Diaper Washing Guide or in our Frequently Asked Questions about cloth diaper washing? Drop by the Real Diaper Association Facebook page to ask additional questions.