What Not to Flush or Pour Down the Drain

The rule is short: toilet paper and human waste, nothing else. Everything below either fails to break down, snags on pipe defects, or binds with grease into the mass that plumbers call a fatberg.

• Wipes of any kind, including those labelled flushable, which pass the toilet and then do not disintegrate
• Paper towels, tissues, and napkins, which are designed for wet strength rather than dispersal
• Feminine hygiene products, which absorb and expand
• Cotton balls, swabs, and dental floss, which catch on anything and bind other debris
• Diapers and wipes packaging, which cause immediate hard blockages
• Medications, which pass through treatment plants into waterways; use a pharmacy take-back
• Cat litter, including varieties labelled flushable, which clumps and sets
• Condoms, hair, and cigarette butts

The label is a marketing claim about whether the product will leave the toilet bowl, not a statement about whether it will break down in the sewer. It will not. Wipes retain their structure through the entire drainage system, catch on joints and roots, and bind with grease into the masses that block municipal sewers and destroy lift station pumps.

Water utilities across the world spend enormous sums removing them, and they are a leading cause of both household lateral blockages and municipal system failures. If a household has a recurring main line blockage and someone in it uses wipes, that is very often the whole explanation.

Grease is to kitchen drains what wipes are to sewers. It goes down warm and liquid, cools within a few feet of pipe, and coats the walls. Over months the effective diameter shrinks, food particles catch on the coating, and the line blocks.

Running hot water while pouring does not solve it; it moves the cooling point further down the line, which puts the blockage somewhere less accessible.

• Cooking grease, oil, and fat: pour into a container, let it solidify, and bin it
• Coffee grounds, which do not break down and accumulate in traps and bellies
• Eggshells, which grind into small sharp fragments that bind with grease
• Pasta and rice, which continue absorbing water and swelling in the line
• Fibrous vegetables such as celery and artichoke, which wrap around disposal blades
• Flour and starches, which form a paste with water
• Paint, solvents, and chemicals, which are an environmental problem as well as a plumbing one

A disposal grinds food into smaller pieces; it does not make those pieces dissolve, and it does nothing at all about grease. Everything ground up still has to travel through the same pipe, and in a line that already has a grease coating, ground food is exactly what catches on it.

Use plenty of cold water when running a disposal, which keeps fats solid so they are carried through rather than coating the pipe, and run it for several seconds after the noise stops to clear the line.