what can go down the drain? Down the toilet: human waste and toilet paper. That's the whole list — Metro Water Services says it in one line: "You can prevent toilet and sewer clogs — only flush toilet paper." Specifically never flushed, per Metro: "flushable" wipes of every kind, paper towels, cotton swabs, feminine products, hair, dental floss, and fats, oils & grease. Down the kitchen drain: water, and food only in the small, soft amounts a disposal is actually built for — grease never, because it leaves the pan liquid and arrives in your lateral as a solid coating.
The flush list, in Metro's own framing
Metro's "Trash the Wipes" guidance (updated October 2025) puts wipes — baby, cleaning, personal — first under "Items that should not be flushed," and gives the reason in homeowner terms: flushing them "might clog up your toilet [and] cause sewage to back up into your house," besides overflowing sewers and damaging the reclamation equipment where wipes wrap around machinery. Their service-line brochure's list is the one quoted above: wipes (in scare quotes in the original — Metro's punctuation, and it earns its place), paper towels, cotton swabs, feminine products, hair, dental floss, and FOG.
Why these items, mechanically? Toilet paper is engineered to fall apart in water within moments. Everything on Metro's list is engineered for the opposite: to stay strong, absorbent or intact when wet. In your lateral they snag — on a joint lip, a root hair, a patch of corrosion or grease — and then they collect each other. The progression in the market research is the one we unclog weekly: single-toilet clog, branch clog, then a mat down the main line, then the whole house backing up at the lowest fixture.
"Flushable" wipes: the label is the problem
A homeowner on Quora asked it plainly: "Is it true that flushable wipes could still clog up your toilet?" The fetched answer was blunter: "There is no such thing as a flush-able wipe even though it says you can on the package." The honest nuance, from a Nashville plumber's own explainer, is that "flushable" generally certifies the wipe can pass through a toilet under test conditions — nobody certified it to dissolve like paper, or to travel safely through your forty-year-old clay lateral, or through Metro's pumps. It may pass your toilet and still clog your pipes further down; utilities note a toilet can appear to work normally for weeks or months while a mat builds downstream.
The costliest version of this lesson in the whole question bank is the landlord case on the same Quora page: tenants' wipes impacted a line so severely that three companies couldn't clear it by pressure or snake, a section had to be dug up and replaced, and the bill — just over $4,500 — landed on the tenants, because the lease put tenant-caused damage on them. Wipes are the rare household product that can generate a four-figure invoice and a lease dispute at the same time. Trash can. Every time.
Grease: cool it, can it, trash it
Grease lies about its state. In the pan it's a liquid; in the lateral it's a coating — it cools on the pipe wall a fraction at a time, narrows the bore, and then traps everything else that passes. Metro's FOG guidance (its FOG Policy has governed food businesses since 2004) applies the same physics to houses: fats, oils and grease are named in the do-not-flush list because downstream, in a main, one kitchen's grease becomes the street's problem. The household routine is the one utilities print everywhere because it works: let it cool, scrape it into a can or the trash, wipe the pan with a paper towel — which then also goes in the trash, not the toilet. Running hot water and detergent after grease doesn't move the problem away; it moves it further down your own pipe before it sets.
The garbage disposal: smaller claims than the name makes
A Quora homeowner asked what should and should not go in a garbage disposal, and the fetched answer is the right frame: nothing inorganic — not even a paper napkin — and care even with the organics; the classic jam is a dropped spoon, and large bones can clog or break the unit. A disposal is a grinder for small amounts of soft food scraps, not a second trash can with plumbing. Fibrous material (celery, onion skins, corn husks) wraps the works; starch loads (pasta, rice, potato peels) swell into paste; coffee grounds — the myth that won't die — don't scour anything, they sediment into the grease film like sand into wet cement. And when the disposal side of a double sink backs up into the other basin, that's the branch telling you the problem has outgrown the fixture — the clogged drain page has the branch-versus-main test, and the kitchen page takes the kitchen line itself apart.
When the list comes too late
If you're reading this because something already won't drain: one slow fixture is a branch problem, several fixtures plus gurgling is the main introducing itself, and sewage at the lowest drain means stop running water now. Our list is $129 for a single fixture and $249 for a main line with the camera before and after — full list on the cost page, and the number is (615) 555-0134. If several houses on your street are backing up at once, that's Metro's side: 615-862-4600, option 3, and their main-clog investigation is free.