Before you begin. This procedure is general reference information, not professional advice. Equipment varies by manufacturer, model, and year. Always follow the documentation supplied with your equipment — where it differs from this page, follow the manufacturer. Verify that you have the tools, the working conditions, and the ability to do this task safely. If anything is unclear, if the equipment is damaged, or if the task exceeds your experience, stop and use a qualified professional. You are responsible for your own safety and for the outcome. This site accepts no liability for any loss, damage, or injury arising from the use of this information.
Specifications marked unverified could not be traced to a manufacturer source. Do not rely on them — obtain the value from your equipment documentation.
A drain that empties slowly, or not at all, is almost always blocked close to the fixture. Hair, soap and grease build up in the trap under the sink, or in the short length of pipe behind it, over months rather than overnight. A cup plunger shifts most of them, cleaning the trap by hand shifts most of the rest, and a hand drain auger reaches what is left. This page covers a sink, a basin, a bath and a shower, and it uses two hand tools and no chemicals.
It also says where to stop. If every drain in the building is slow at the same time, the blockage is not under your sink and nothing here will reach it. That is a plumber's job, and the page says so rather than sending you further down a pipe you cannot see. We do not print a chemical drain cleaner dose or a temperature limit for your pipe, because neither can be traced to a source that applies to your plumbing.
DO NOT DO THIS PROCEDURE IF A CHEMICAL DRAIN CLEANER IS IN THE FIXTURE.
The chemical can splash and burn your skin and your eyes.
| Item | Note |
|---|---|
| Cup plunger | The cup must be larger than the drain opening. |
| Hand drain auger | Use a hand drain auger for a fixture drain. |
| Rubber gloves | The gloves must cover your wrists. |
| Eye protection | Use safety glasses or goggles. |
| Bucket | The bucket must go below the trap. |
| Stiff brush | The brush must go into the trap. |
| Old towels | The towels keep the water off the floor. |
| Adjustable wrench optional | Use the wrench only if the nuts do not move by hand. |
| Flashlight optional | Some drain openings are in a dark space. |
| Hot water material | Water from the hot tap is enough. |
| Refuse bag material | Put the waste from the trap into the bag. |
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
Estimated 4 min
Estimated 1 min
PUT ON THE GLOVES AND THE EYE PROTECTION BEFORE YOU TOUCH THE DRAIN.
Waste water has bacteria in it.
Estimated 5 min
DO NOT USE MORE FORCE THAN NECESSARY WITH THE PLUNGER.
Too much force can cause damage to an old waste pipe.
Estimated 9 min
DO NOT REMOVE THE TRAP IF A CHEMICAL DRAIN CLEANER IS IN THE FIXTURE.
The liquid in the trap can burn your skin.
LOOSEN THE NUTS ON THE TRAP BY HAND ONLY.
A tool can cause damage to a plastic nut.
Estimated 9 min
PUT ON THE GLOVES BEFORE YOU TOUCH THE DRAIN AUGER.
The end of the auger is sharp and can cut your hand.
Estimated 5 min
This page uses one term for each item and holds it throughout, as ASD-STE100 requires. Equipment sellers and other guides use the names below for the same parts.
Stop if all the drains in the building are slow at the same time. The blockage is then in the building drain. Speak to a plumber.
Stop if waste water is at a floor drain. Stop if waste water is outside the building. Stop if the fixture has a leak that you cannot stop. Speak to a plumber.
Do not use a chemical drain cleaner to clear a drain. Do not put a powered drain machine into a pipe. This page does not give a chemical dose. This page does not give a temperature limit for your pipe. Ask the manufacturer of the pipe for these values.
Start at the fixture, because that is where almost every household blockage sits. A cup plunger clears most of them in under a minute. The trap under the sink, the U-bend, is the next place to look, and cleaning it out by hand is often the whole repair. If the plunger and the trap both come up empty, a hand drain auger will reach the short run of pipe behind the wall. Beyond that you are into the building's drain, which is a plumber's job.
This page does not tell you to, and it will not print a dose or a contact time for one. Caustic drain cleaners are sodium or potassium hydroxide, and ATSDR describes direct contact with concentrated solutions as causing thermal and chemical burns leading to deep-tissue injuries, with severe eye damage in strong solutions. The Army's own plumbing manual makes a separate practical point: chemical cleaners have to reach the blockage to do anything, so they should not be used in a pipe that is already fully stopped. What happens instead is that the caustic liquid stands in the fixture, and then it is the thing you plunge, unscrew or splash. Mechanical clearing has none of those failure modes, which is why it is the whole of this page.
Because the blockage is on that fixture's own branch, upstream of the point where it joins everything else. That is good news: it is the short, accessible part of the system, and it is the part this page covers. The Army plumbing course uses exactly this test to place a stoppage. One fixture affected means its own branch line, and every fixture affected means the main line.
A plunger moves the water in the pipe and breaks the blockage apart with it. A drain auger, the snake, is a flexible steel cable you feed down the pipe to reach the blockage physically. Try the plunger first: it is faster, it is cheaper, and it cannot scratch the inside of a trap. Use the auger when the plunger has had three honest attempts and the water still stands.
It means the blockage is downstream of everything, in the building's main drain rather than in any one fixture. Nothing on this page reaches that. It is cleared through a cleanout with heavy equipment, and it is a plumber's job. If waste water is appearing at a floor drain or outside the building, stop using water in the house and call one now.
That is the trap, and the water standing in it is a seal. It stops drain smells and insects coming back into the room, which is why a trap must never be left off overnight. It is also the narrowest and lowest point on the fixture's drain, so it is where hair and grease collect first. That is why cleaning it out by hand fixes so many slow drains.
No related procedure is published yet. This section fills as the repository grows.
Every specification on this page is traced to one of these sources. Tier 1 is a manufacturer document, a published standard, or a government safety authority. See Standards for the full tiering rule.
Current version 1 · updated 2026-07-29 · next review due 2027-07-29
Corrections to this page are listed in the public corrections log. Reports that are credible and not yet verified are listed in the public errata register, and an open one renders above the step it concerns.
Found an error? A correction with a manufacturer source is applied and logged publicly. You can also write to corrections@fixchecklist.com.
Every step above carries its own report control, which tags the report with that step so a correction reaches the right place. For anything about the procedure as a whole — the order of the sections, a step that is missing, something that did not match your equipment — use this: report something about this whole procedure.