In accordance with California’s Proper Labeling of Wet Wipes law (AB818), the California Association of Sanitation Agencies (CASA), the Responsible Flushing Alliance (RFA), and the Association of the Nonwoven Fabrics Industry (INDA), have partnered to conduct a sewage collection study to help determine what is clogging sewer lines and equipment across the state.

“As a co-sponsor of the Proper Labeling of Wet Wipes law, we recognized the importance of educating Californians about not treating their toilets as a trashcan,” says Adam Link, Executive Director of CASA. “We’ve all seen the huge rag balls pulled from clogged sewer lines, and through this study we are taking a forensic approach by untangling those products and determining what is actually being flushed. These efforts will help inform our educational outreach.”

The two locations for the study include the Inland Empire Utilities Agency (IEUA) in Southern California and Central Contra Costa Sanitary District (Central San) in the greater San Francisco Bay Area in Northern California. The collections and forensic analysis are underway with the “dry season” studies taking place this month and the “wet season” studies taking place this winter, if required pending dry season final results outcome.

Preliminary collection study results from IEUA (Oct. 11-12) and Central San (Oct. 17-18) showed 94% of items collected were paper (53%), wipes labeled with the “Do Not Flush” symbol (34%) and feminine hygiene products (7%). Less than 1% of items collected so far were considered to be flushable wipes. The baby wipes and other non-flushable items were found mostly fully intact.

Some of the more unusual items collected include an action figure, hair weave, pet mouse, banana peel, a knee sock, rubber bands, cloth towels and a plastic toy frog. Also observed before the collection period started were other toys, syringes, condoms and underwear.

“With approximately 90% of wipes sold in the U.S. being non-flushable, it makes looking for the ‘Do Not Flush’ symbol and following disposal instructions exceptionally important,” says Responsible Flushing Alliance President Lara Wyss. “Non-flushable wipes are engineered to be different from flushable wipes. Non-flushable wipes are made with long, often plastic fibers that are meant to be strong. Flushable wipes are made with 100% plant-based fibers and are designed to break down in water, similar to toilet paper.1” 

Kennedy-Jenks, an independent engineering firm, was hired to design the collection study and compile the findings in a report, due during the first half of 2024. Study parameters include pulling raw sewage samples from the headworks during peak flow times. Analysis of the items spans four days of sorting with more than 1700 items identified in the “dry season” sample alone.

“To make accurate identifications, we purchased over 150 wipes brands and types to compile a sample book for comparing markings and patterns,” says Matt O’Sickey, PhD, INDA’s Director of Education & Technical Affairs. “We also enlisted the expertise of technical leaders and material scientists from INDA member companies to lead the identifications of wipes and other items. By using a magnifying glass, gently pulling at the fibers and examining them, as well as comparing them to our sample book, we are individually inspecting each item carefully.”

Categories for items identified include all baby wipes and other non-flushable wipes outlined in the Proper Labeling of Wet Wipes law, feminine hygiene products, flushable wipes (moist toilet tissue), and non-flushable paper products (paper towels, wrappers).

Once collected, sample items are separated, identified, and documented by taking a picture of each piece and writing its description in a collection logbook. A count of one item is considered any material measuring one inch or more in two dimensions.

“There is a lot of consumer confusion around what should or should not be flushed and that’s where our consumer education campaign, #FlushSmart, comes into play,” Wyss said. “We surveyed Californians about what they are flushing. The results showed that 20 percent mistakenly think all soft paper products can be flushed and approximately 25% think baby wipes are flushable, which is never true. Even worse, 60% self-reported they flushed something they knew they shouldn’t.”

According to the Proper Wet Wipes Labeling law, manufacturers of non-flushable wipes, including products such as baby wipes, cleaning wipes, makeup removal wipes, and many others, that are primarily used in a bathroom setting must include the “Do Not Flush” symbol on the front of packaging. The #FlushSmart consumer education campaign promotes the “Do Not Flush” symbol and provides information on what should and should not be flushed.