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  • Writer's pictureJenna Granger

Toilet Science

Updated: Dec 22, 2020

What is really flushable?

Grade Level:



Environmental Science

  • Watershed Protection

Physical Science

  • Properties of Matter

Tools & Materials

  • Toilet paper

  • Wipes of any sort (cleaning wipes, baby wipes, “flushable” wipes)

  • Paper towel

  • Facial tissue paper (kleenex)

  • Cotton balls or swabs

  • Mason jar with lid (or any cup/container that can be sealed)

  • Strainer or colander

  • Water

  • Science notebook or paper & pencil

To Do & Notice

1. Question:

  • What is flushable? Can paper products like wipes, paper towels, facial tissues, cotton swabs or cotton balls be flushed down the toilet? Note: For items to be flushable, they must easily disintegrate (or break down) in water.

2. Make a Claim:

  • What items do you think can be flushed down the toilet?

3. Testing Ideas:

  • Fill the mason jar (or container with lid) half full of water and place one item into the jar.

  • Vigorously shake the jar for 30 seconds (to simulate a toilet flushing).

  • After 30 seconds, stop shaking and make an observation. Has the item disintegrated?

  • Continue shaking the jar for another 30 seconds.

  • Remove the item from the jar by pouring it into your colander or strainer (over a sink or bucket).

  • Observe what happened to the item.

  • Remove the item from the colander or strainer and place in the trash can.

  • Repeat these steps with all of the items you are testing (toilet paper, wipes, paper towels, tissue).

  • If you are keeping a science notebook, write your observations and results next to each item you test.

4. Analyze & Interpret Data:

  • If the item was able to pour through the strainer leaving nothing behind, then it is flushable.

  • If the item stays in the strainer, it is not flushable.

  • You should have found that only toilet paper fully disintegrates (breaks down). All other paper products, including “flushable” wipes, do not break down and therefore are not flushable.

  • Consumer Reports conducted a similar experiment and found that many wipes did not disintegrate even after 10 minutes in a mixer. Watch the video here: Consumer Reports: Are flushable wipes flushable?

5. Communicate Findings:

  • Tell your friends and family about your experiment & results. As we face toilet paper shortages, many people may be tempted to use other paper products and flush them down the toilet. Let them know those items are not flushable and need to be thrown away instead. Only toilet paper and human waste can be flushed!

  • Share your results with SWEP by sending us photos or videos of your experiment. Post your photos on social media and tag us @sweptahoe on Instagram and/or to @swep4 on Facebook. Be sure to hashtag and follow #SWEPsnippets. If you cannot post directly yourself, send your photos or video to SWEP (

What’s Going On

  • What Can be Flushed: Human Waste & Toilet Paper

  • What Cannot be Flushed: Anything other than human waste and toilet paper. All wipes, paper towels, tissue paper, cotton ball, cotton swabs, floss, diapers, grease, etc. cannot be flushed and should be thrown away in the garbage.

  • A Note from North Tahoe Public Utility District (NTPUD): “NTPUD has 4 main pump stations that transport the sewage out of the basin to the Tahoe Truckee Sanitation Agency. In recent years, these pump stations have been experiencing clogs in the pumps. The material clogging the pumps is cloth like, has a high tear strength, and is not disintegrating, dissolving, or decomposing in the collection system. DO NOT use Your Toilet As A Trash Can! Flushable does not mean dissolvable! Clogging of these pumps can cause a sewer spill and because most of these pump stations are at or near Lake level, these could cause sewage overflows into Lake Tahoe.” Please read the NTPUD article: “Protect Your Health, Your Home, Our Lake!”


  • North Tahoe Public Utility District: Save the Pipes! Don’t Flush Wipes” (included below)

Going Further

1. Upcycle your toilet paper tubes with these art & science activities:

2. Bathroom Science:

This book by Christine Taylor-Butler offers 70 home experiments that can be done in the bathroom.

Thank you to our partners at North Tahoe Public Utility District and Truckee Donner Public Utility District for supporting student’s science learning activities.

Please review SWEP's Terms of Use prior to using this resource.

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