Before you start: one fixture, or several?
This determines whether anything below is worth attempting.
One slow fixture, everything else fine. That fixture's trap or branch line. Proceed.
Two or more at once, or a toilet that makes a tub gurgle, or water rising in a shower when the washing machine drains — that is a shared restriction in the main line. A plunger will not reach it, and vigorous plunging can push waste water up into whichever fixture sits lowest.
Stop and get the main line looked at instead. The signs are covered in what each sewer symptom means.
Step one: the plunger, used properly
Most plunging fails on technique rather than on the blockage.
Use the right shape. A flat cup plunger is for flat surfaces — sinks and tubs. A flange plunger, with the extra sleeve that folds out, is for toilets. The flat one cannot seal a toilet outlet and mostly moves air.
Cover the overflow. A basin or tub has an overflow opening, and if it is open your plunging pushes air out of it instead of pressure down the pipe. Block it with a wet cloth held firmly. This one step is the difference between working and not.
Get water over the cup. Plunging in air accomplishes nothing — you need water, which does not compress, to transmit the force.
First push gentle, then firm. A hard first thrust just splashes. Then steady strokes maintaining the seal, fifteen to twenty. It is the pull that usually shifts the blockage, not the push.
On a double sink, block the other side. Otherwise the pressure simply goes up the second drain.
Worth knowing
If you have already poured chemical drain cleaner in, do not plunge. You will splash a caustic solution around, and possibly onto yourself. That is one of the more practical reasons to skip the chemicals in the first place.
Step two: the trap
The U-bend under a sink is where most kitchen and bathroom blockages actually sit, and removing it is more straightforward than people expect.
Put a bucket underneath — it is full of water and it will all come out. Loosen the two slip nuts by hand where possible, or with slip-joint pliers, protecting plastic nuts with a cloth.
Clean it out fully, including the arm running into the wall. Check the washers while it is apart; they are cheap and a perished one causes the drip people notice a week later.
Reassemble hand-tight plus a nudge. Overtightening cracks plastic nuts, and that turns a free fix into a parts run.
Then run hot water and watch every joint for a full minute before walking away.
Step three: a hand auger, and where to stop
If the trap was clean, the blockage is further along, and a hand auger (drain snake) is the next and last step worth attempting yourself.
Feed it in gently and crank steadily. When you meet resistance, keep turning rather than shoving — you are trying to bore through or hook the obstruction, not ram it.
For a toilet, use a closet auger specifically. It has a protective sleeve to stop the cable scratching the porcelain, and that scratching is permanent.
Stop and call if: the auger will not pass a certain point, the blockage returns within days, more than one fixture is now affected, or you are working on the main line. Beyond that point, forcing tools risks damaging older pipe — and if the line is failing structurally, no amount of clearing will hold.
The tell that matters most: a properly cleared line stays clear. One that blocks again within months is catching on something structural, and that needs a camera rather than another clearing.
What professionals use, and when it is warranted
A powered drum machine reaches much further with far more torque and cuts through root masses a hand auger cannot touch. It is also capable of damaging old or compromised pipe, which is why the operator matters as much as the machine.
Hydro-jetting uses high-pressure water to scour the pipe wall rather than punch a hole through the blockage. That distinction matters: an auger makes an opening through grease, and the grease that remains starts catching material immediately. Jetting removes the buildup, so the line stays clear far longer.
Jetting is not for every pipe — it needs a line sound enough to take the pressure, which is another reason a camera comes first on anything that has failed repeatedly.
The honest position: for a one-off kitchen sink blockage, a plunger and a trap clean are the right answer and we will say so. For a line that has backed up three times, clearing it a fourth time is selling you the same afternoon again.
Why chemical cleaners are on the excluded list
They work by generating heat and reacting with the blockage, and on a light, partial clog they sometimes appear to succeed.
What they cannot do is clear a root mass, a sag holding standing water, or a wipe accumulation — the things that cause the repeat problems people actually call about. On those, the product sits in the standing water doing nothing.
It is then a hazard for whoever opens the pipe, including you if you decide to plunge afterwards.
Repeated use damages older pipe and rubber seals, and the heat generated can deform PVC. On a main line backup it is wasted money at best.
Prevention beats all of it: a hair catcher on every shower and basin, no grease down the sink, and nothing but waste and toilet paper down a toilet. The full list is in what never goes down a drain.