Almost every plumbing call we run starts with a single observation: a drain is not working. Sometimes it is a sink that has been getting slower for weeks; sometimes it is a basement floor drain that just sent water across the laundry room at 11 p.m. Knowing why your drain is clogged — and which kind of clog you are dealing with — decides whether you grab a plunger or pick up the phone.

First, the diagnostic question

Before you do anything else, answer this: is it one fixture that is acting up, or multiple fixtures at once?

One drain only (a single sink, tub, shower or toilet, slow or stopped): the clog is local — within a few feet of the drain, in the trap, the branch line or the immediate fixture itself. Usually a DIY fix.
Multiple fixtures backing up (the shower gurgles when the toilet flushes, water rises in the bathtub when the washing machine drains, the basement floor drain overflows): this is a main sewer line problem. Everything in the house is trying to leave through the same blocked pipe. Stop running water and call.

This single question routes you correctly. People often spend an hour on a plunger when the main line is the problem, and end up with sewage on the floor.

Why single drains clog

The boring causes are usually the right ones.

Bathroom drains clog with hair and soap scum. Hair traps soap, soap holds more hair, and over months you have a felt-like wad just below the strainer. Combs and bobby pins are surprisingly common too.

Kitchen drains clog with grease, food debris and coffee grounds. Grease that goes down warm and liquid hardens further down the line where it is cooler. Coffee grounds are sand-like and accumulate at the bottom of pipe bellies. Pasta, rice and "flushable" wipes (which are not) round out the list.

Toilets clog with too much paper at once, with non-flushable items — wipes, paper towels, cat litter, dental floss — and occasionally with the toys young children find fascinating to flush.

Floor and laundry drains clog with lint, hair, and the gunk that washing machines push down their standpipes. They are also a leading indicator of a main-line issue, because they are the lowest point in many houses.

Why drains in older Omaha homes clog more

Some clogs are not really clogs. They are the pipe itself.

In pre-1960s homes in neighborhoods like Dundee, Benson, and older parts of Midtown, the drain stacks are usually cast iron. Cast iron is durable but scales internally over decades. The interior of a pipe that started at 2 inches in 1925 might be effectively 1.5 inches now, with a rough, debris-snagging surface. The pipe is not clogged in the conventional sense; it is just permanently narrower. That kitchen sink will keep "clogging" until the pipe is replaced.

Galvanized branch drains have the same issue. If you live in an older home and the same drain keeps slowing down within weeks of clearing, the pipe itself is likely the problem.

Main-line clogs: roots, bellies and the rest

A whole-house clog is a different conversation. The most common causes:

Tree root intrusion in clay-tile or older cast-iron sewer laterals. Mature elms, silver maples and willows in older Omaha yards send roots through any small gap or joint, then keep growing inside. Once roots are in, every flush adds material that catches on them. Snaking with a root cutter buys time; permanent fixes are covered on our sewer line repair page.
A belly in the line — a settled section where waste pools instead of flowing. Common where old fill or expansive soil moved under the pipe. A camera tells us immediately if this is happening, and it is not solved by snaking.
A foreign object lodged at a turn or transition. Toys, "flushable" wipes, accumulated grease, even broken pieces of pipe wall.
A collapsed or offset section — old clay tile is brittle, and a single bad freeze-thaw cycle or a heavy vehicle on the yard can crack or push a section out of alignment.

If the drain cleaner you just bought is the third one this year, the answer is not a fourth bottle.

Things to try yourself (and one not to)

For a single slow fixture, in order of effort:

Hot water down a kitchen drain that is slow with grease. Not for a fully blocked drain — you will just have hot water in a sink.
A plunger. The right tool for sinks and toilets. Seal the overflow opening on a bathroom sink with a wet rag for proper suction.
A hand auger (drain snake) — about $25 at any hardware store. Most effective on bathroom sinks, tubs and showers, and toilets. Wear gloves.
Remove and clean the P-trap under a sink. Put a bucket underneath. Half the bathroom sink clogs we see could have been a 5-minute job for the homeowner.

Do not use chemical drain cleaners on a real clog, and avoid them entirely in older homes. They rarely clear a true blockage, they can corrode metal traps and aging cast iron, and the residue makes the plumber's job riskier when the line is finally opened. If a plunger and an auger have not worked, the next step is a professional, not a stronger chemical.

A quick word on garbage disposals

A surprising number of kitchen-drain calls trace back to the disposal — not because it is broken, but because of what is going into it. Coffee grounds, eggshells, potato peels, rice, pasta, fibrous vegetables like celery and onion skins, and anything starchy will accumulate downstream of the disposal where the pipe slopes off. The disposal grinds them small enough to look like they are gone, but they pile up at the first elbow in the line. Run the disposal with plenty of cold water, keep the high-volume starches and fibers out of it, and pour a kettle of hot water down the drain once a week as preventive maintenance. None of this is a substitute for a real clog fix, but it heads off a lot of repeat calls.

How a plumber actually clears a drain

For a single fixture, a small motorized snake or a hand auger does the job. For a main line, the proper tool is a motorized drum machine with the right cutter head for the pipe and the situation — root cutter for roots, blade head for grease and debris. For badly fouled commercial lines or heavy grease, hydro-jetting scours the pipe wall and is more thorough than a snake; for severe root masses, it is sometimes the difference between buying months and buying years.

For any recurring main-line issue, a camera inspection is the cheapest investment you will make. It costs less than another year of "I'll snake it again" and it tells you exactly what is happening, where, and what the right repair is. Our drain cleaning service includes camera inspection when the situation warrants.

If you have an active backup right now and the water is rising, do not run any more fixtures, and call our 24/7 emergency plumbing line. If you suspect the bill for the eventual repair will be in the higher range, our guide on how much an emergency plumber costs in Omaha gives you the honest ranges.

When to call

Call as soon as a single drain stops responding to plunging and a hand auger, or any time you see whole-house symptoms — multiple slow drains, gurgling, water at the basement floor drain. A recurring "clog" that keeps coming back is almost always trying to tell you something specific, and a camera tells you what — usually faster and cheaper than guessing for another six months.

Why Is My Drain Clogged? Causes and Real Fixes