RALEIGH — Another sewer line became clogged in Raleigh over the weekend, and city officials are once again pointing the finger at so-called flushable wipes.
A sewer overflow on Marlowe Road can be traced back to a line clogged by the wipes and paper towels, city officials said Monday. The overflow started sometime early Saturday and lasted for about 15 hours before a homeowner reported it Saturday evening.
By the time city crews were able to stop the spill, an estimated 39,750 gallons of wastewater had overflowed into an unnamed tributary to nearby Crabtree Creek. Workers expected to have the spill cleaned up by late Monday.
The city responded to 29 sewer overflows like this, of 1,000 gallons or more, in the year ending last June 30. To prevent them, the city has for years waged a campaign to discourage people from pouring cooking grease down the drain, going so far as to collect it at the curb during holiday cooking season, from Nov. 1 until Jan. 15.
But grease is the second leading cause of sewer clogs in Raleigh, after debris, including paper products other than toilet paper, which caused 28 percent of them, according to the city.
One of the most common forms of debris are “rags,” including hygienic wipes, some of which are advertised as safe to flush. The problem, says Raleigh Public Utilities Director John Carman, is that many of the wipes don’t actually break down.
“There is this notion that somehow they’re safe to flush down the toilet,” Carman said. “Flushable wipes don’t always disintegrate.”
Several years ago, the city tested various paper products, including facial tissues and wipes, to see how quickly they disintegrated in a beaker of swirling water. Toilet paper began to fall apart almost immediately, while the tissues and wipes – even those sold as flushable – remained almost completely intact.
Thicker and heavier than toilet paper, wipes often stick to the sides of pipes or on other obstructions in the sewer lines, making small problems much bigger, city officials say.
The Association of the Nonwoven Fabrics Industry, based in Cary, has heard these complaints before. INDA has developed industry guidelines for determining what qualifies as a “flushable” wipe, and says its tests show that wipes that meet the guidelines do break down in a reasonable amount of time.
The association does allow that consumers may flush wipes that aren’t designed to be, however. It has developed a “No Flush” logo that it encourages its member companies to include on non-flushable wipe products.
But Raleigh officials still insist on a no-wipe stance. Sanitary products, paper towels, facial tissue and wipes, even the flushable kind, should all be placed in the garbage, said Carolyn Dumas, public information officer for the city’s public utilities department.
“Only water, human waste and toilet paper are permitted to be discharged into the sewer system,” Dumas said.