Unclog Drain: Step-by-Step Guide & Costs

By Mohammad Barzegar, Director, TQN Plumber · Reviewed by a licensed NSW plumber · Updated October 2026 · 11 min read

The quickest way to unclog a drain is to lift the grate, pull out the hair or food scraps, then plunge the plughole with a cup plunger. If several fixtures drain slowly at once, or water rises in the shower when you flush, the blockage is in your pipes and needs a licensed plumber.

Below are five safe ways to unblock a drain at home, how drain unblockers and drain acid compare, and what Sydney plumbers charge.

What you need to unclog a drain

Most of what you need to unclog a drain is already under your kitchen sink.

Item	What it’s for	Price band (indicative)
Cup (sink) plunger	Flat rubber cup that seals over a sink, basin, bath or shower plughole to push and pull a blockage loose	$
Plastic drain snake (hair grabber)	Thin barbed strip that hooks hair out of shower, bath and basin wastes without scratching chrome	$
Rubber gloves and eye protection	Protect your skin and eyes from dirty water, and from splash-back if anyone has already used a chemical	$
Bucket, old towels and a torch	Catch water, protect floors and cabinetry, and let you see into the waste	—
Dishwashing liquid, bicarb soda and white vinegar	Gentle household cleaners that loosen soap scum and light grease on slow drains	$
Enzyme drain pipe cleaner	Bacterial product that slowly digests organic build-up; better for prevention than for a drain that’s already blocked	$–$$
Electric drain machine, jetter and CCTV camera	The right tool to unblock drain pipes beyond the fixture, from fat build-up to tree roots in the sewer	Plumber only

5 ways to unclog a drain at home (easiest first)

Work through these in order and stop once the water runs freely. Each way to unclog a drain here works at the plughole, grate or the fixture’s own trap only.

1. Clear the grate and plughole by hand

1. Put on gloves and remove the grate or pop-up plug, unscrewing it if needed, so you can see straight into the waste.
2. Pull out the hair, soap and debris you can reach; in showers, the plug of hair usually sits just below the grate.
3. Scrub the underside of the grate and plug, because the slimy film left behind catches the next lot of hair within weeks.
4. Bin the waste rather than rinsing it away in another fixture, or you’ll simply move the blockage somewhere else in the house.
5. Run hot tap water for a minute to test the flow; if it still pools, move on to the plunger.

2. Plunge the plughole with a cup plunger

1. Block the overflow hole with a damp cloth, and plug the second bowl of a double sink, so pressure goes down the drain instead of escaping.
2. Leave enough water to cover the rubber cup, because a plunger moves water far more effectively than it moves air.
3. Seat the cup flat over the plughole and press down slowly to squeeze out trapped air and form a tight seal.
4. Pump 15–20 times with firm, even strokes; pulling up drags the clog back and forth, which breaks it apart faster than pushing alone.
5. Lift off and watch the water level; a quick swirl means it’s clear, so finish with hot tap water to rinse the pipe.

3. Hook out hair with a plastic drain snake

1. Feed the barbed strip slowly into the plughole until you feel resistance, without forcing it past the bend of the trap.
2. Twist the handle a few turns so the barbs grab the hair and soap that have knotted together in the waste.
3. Pull it out steadily over a bin bag; in a shower or basin, expect a long grey clump that smells worse than it looks.
4. Repeat two or three times until the strip comes out clean, because hair often catches in more than one spot.
5. Run hot tap water for a minute to flush loose strands through, then bin the strip or wash it outside.

4. Flush a slow drain with detergent and hot water

1. Squirt a generous amount of dishwashing liquid into the plughole so it coats the grease and soap scum lining the pipe.
2. Wait 10–15 minutes to give the detergent time to soak into the build-up on the pipe walls.
3. Pour a kettle of hot, not boiling, water slowly; boiling water can damage plastic pipe joints and crack cold porcelain or enamel.
4. Repeat once if the water starts moving but still drains slowly, as a second dose often shifts what the first loosened.
5. Finish with the plunger, because a lubricated blockage usually slides through after a few firm strokes.

5. Use bicarb soda and vinegar on a slow drain

1. Use this on slow drains only, not a full blockage; it fizzes and loosens soft build-up but creates no real pressure.
2. Pour half a cup of bicarb soda into the plughole, then slowly follow with a cup of white vinegar to avoid overflow.
3. Cover the plughole for 30 minutes with the plug or a wet cloth, so the fizzing works down the pipe.
4. Flush with a kettle of hot tap water to rinse the loosened gunk through the trap and into the line.
5. Never combine it with drain cleaner or bleach; our guide to cleaning drains with baking soda and vinegar explains when it works best.

Unclog a drain by location: shower, sink, basin and outdoor drains

Where the drain is tells you most of what’s blocking it. In older Sydney homes, a slow shower often turns out to be a cast-iron or clay line further down rather than hair.

Drain	Usual culprit	First DIY fix	Plumber job when…
Shower drain blocked	Hair knotted with soap scum and conditioner	Lift the grate, hook out hair, plunge	Water pools after every shower or rises when the toilet flushes
Kitchen sink	Fat, oil, coffee grounds and food scraps	Detergent and hot water, then plunge with the other bowl sealed	It stays slow after plunging, or the dishwasher backs up into the sink
Bathroom basin	Hair, toothpaste and soap around the pop-up plug	Remove and clean the plug, then use a drain snake	The basin and shower are slow at the same time
Laundry floor waste	Lint, sand and hair	Lift the grate and scoop out debris	Water comes up through the floor waste
Outdoor stormwater drain	Leaves, silt and roots	Clear leaves from the grate and gutters	The yard floods in rain or water backs up out of the pit

• To fix a blocked shower drain for good, clean the grate and waste every few weeks; our how to clean a shower drain guide shows the routine.
• To clear sink drain blockages, scrape plates into the bin first and follow our how to unclog a sink guide for double bowls.
• For outdoor pits and grates, leaves and silt are the usual cause; the blocked stormwater drain guide covers what you can safely clear.
• If one drain smells but still flows freely, the trap may be dry or slimy rather than blocked; read about bathroom drain smell causes.

Drain unblockers compared: plungers, snakes, drain acid and sewer unblockers

Supermarket shelves are full of products that promise to unclog a drain overnight. Here is how they really compare.

Method	Works on	Doesn’t work on	Risk
Cup plunger	Hair, soap and food blockages close to the plughole	Roots, objects deep in the pipe, sewer blockages	Low
Plastic drain snake	Hair in shower, bath and basin wastes	Grease, roots, anything past the trap	Low
Detergent, hot water, bicarb and vinegar	Slow drains with soap scum or light grease	Full blockages	Low (never use boiling water)
Enzyme drain pipe cleaner	Ongoing organic build-up when used regularly	A drain that’s already fully blocked	Low, but slow to act
Caustic drain unblockers (gel or crystals)	Some grease and hair blockages	Roots, wipes, objects	High: chemical burns, heat, damaged chrome and seals
Drain acid sold as a sewer unblocker	Heavy organic blockages, in trained hands	Roots, broken pipes, anything solid	Very high: severe burns, toxic fumes if mixed, damaged fixtures
Plumber’s drain machine, jetter and CCTV	Roots, fat build-up, sewer and stormwater lines	—	None to you; costs more

• The best toilet unblocker is still a flange plunger, not a chemical; our how to unblock a toilet guide walks you through it.
• If you use any chemical drain unblocker, wear gloves and eye protection, open a window, follow the label exactly and never plunge afterwards.
• Never pour drain acid into a fixture holding standing water, or one where another product has gone in; the reaction can boil and spit back.
• Plumbers clear grease and roots with water, not acid; see how hydro jet drain cleaning works and when it’s worth it.

Why drains block: causes, signs and fixes

Cause	Sign you’ll notice	Fix	DIY or plumber
Hair and soap scum	Shower or basin drains slowly; water pools around your feet	Clean the grate, drain snake, plunger	DIY
Fat, oil and food scraps	Kitchen sink slow, greasy smell from the plughole	Detergent and hot water, plunger; jetting if it returns	DIY first, then plumber
Wet wipes and sanitary products	Toilet and nearby drains block again and again	Drain machine or jetting	Plumber
Tree roots in old clay sewer pipes	Several fixtures slow, gurgling, overflow gully spilling	CCTV inspection, cutting and jetting, relining	Plumber
Collapsed, cracked or sagging pipe	Recurring blockages, a wet or sunken patch in the yard	Pipe repair or relining	Plumber
Leaves and silt in stormwater	Yard floods in heavy rain, downpipes overflow	Clear grates and gutters; jet the pipe	DIY at the grate, plumber for the pipe

What not to do when you unclog a drain

• Don’t plunge after pouring in a chemical cleaner; the plunger can splash caustic or acidic water onto your face, eyes and arms.
• Don’t mix drain products or add bleach, because some combinations release toxic gas or boil up out of the plughole.
• Don’t pour boiling water down the drain; sudden heat can damage plastic pipe joints and crack cold porcelain, enamel or acrylic.
• Don’t push a wire coat hanger down the plughole; it scratches chrome, can pierce plastic traps and usually packs the clog tighter.
• Don’t open the overflow relief gully or a sewer inspection opening when sewage is backing up; that’s work for a licensed plumber.
• Don’t keep running water into a blocked fixture to force it through, or you risk an overflow onto floors and into cabinetry.

When to call a plumber to clear blocked drains

• More than one fixture is slow at once, such as the shower and basin together, which points to a blockage further down the shared line.
• Water rises in the shower or floor waste when you flush, meaning the main sewer line is blocked rather than one fixture.
• You hear gurgling from plugholes or smell sewage outside, especially around the overflow relief gully near the house.
• The same drain blocks again within weeks, which usually means roots, fat build-up or a damaged pipe; see the signs of a blocked sewer drain.
• Water is leaking under the sink or around a floor waste, which can damage cabinetry, flooring and the waterproofing beneath tiles.
• Drain flies keep hovering around one plughole, a sign of sludge deep in the pipe; read how to get rid of drain flies.

Sydney Water lists clearing blockages in private wastewater pipes as work for a licensed plumber. If you can’t unclog a drain from the plughole, the grate or the fixture’s own trap, stop there.

What a plumber charges to unclog a drain in Sydney

Service (Sydney, Oct 2026)	Price range	Typical
Call-out fee (incl. GST)	$69–$170	$140
Hourly rate (incl. GST)	$92–$230	$140
After-hours hourly rate	$170–$345	$255
Standard blocked drain clear	$150–$500	$320
Blocked drain with CCTV and jetting	$350–$1,100	$700
After-hours or emergency visit	$290–$805	$520

• Ask for a fixed price before work starts, so a simple blockage isn’t billed open-ended by the hour.
• Ask whether CCTV is included if the drain keeps blocking, because the camera shows roots or breaks you’d otherwise pay to clear again.
• Ask for a Certificate of Compliance for any pipe repair; it confirms the work meets the Plumbing Code of Australia.
• Compare rates in our Sydney plumber cost guide before you book, and avoid after-hours rates if the drain can wait.

How to stop your drains blocking again

• Fit a hair catcher over shower and basin plugholes and empty it weekly; it’s the cheapest way to avoid a blocked shower drain.
• Wipe greasy pans with paper towel and bin cooled fat, rather than pouring it down the kitchen sink where it sets in the pipe.
• Flush only toilet paper and human waste; wet wipes labelled “flushable” still don’t break down in sewer pipes.
• Run hot tap water and detergent down kitchen and basin drains weekly to stop soap and grease building up on the pipe walls.
• Keep leaves out of gutters, downpipes and stormwater grates, especially before storm season in leafy Sydney suburbs.
• Book a CCTV check if you have old clay sewer pipes and big trees nearby, so roots are cut before they cause a backup.

Unclog drain FAQs

How do you unblock a drain?

Start at the plughole. Lift the grate, pull out hair or food scraps, then plunge with a cup plunger while the overflow is blocked. Follow with detergent and hot tap water. If the water still sits there after two or three proper attempts, the blockage is past the trap and needs a licensed plumber.

How do you unblock drains at home without chemicals?

To unclog a drain without chemicals, use a cup plunger, a plastic drain snake for hair, and dishwashing liquid with hot (not boiling) water. Bicarb soda and vinegar help on slow drains. These cost little, won’t burn you and won’t harm your pipes. Skip caustic products and drain acid, which are risky to handle and rarely fix a deep blockage.

How do you clear a clogged drain that won’t drain at all?

A fully blocked drain needs mechanical force, so skip bicarb and vinegar. Clean the grate, then plunge firmly with the overflow sealed. If nothing moves, stop before the fixture overflows. A full blockage beyond the trap usually needs a plumber’s drain machine or jetter, and Sydney Water lists that as licensed work.

How do you fix a blocked shower drain?

Unscrew or lift the grate, pull the hair out with gloved fingers or a plastic drain snake, and scrub the grate clean. Plunge the waste, then run hot tap water. If the shower still pools, or water appears when the toilet flushes, the blockage is further down and needs a licensed plumber.

How do you clear a drain blockage further down the pipe?

First work out where it is. One slow fixture usually means the blockage is near that plughole or trap. Several slow fixtures, gurgling or a spilling overflow gully mean it’s in the shared line or sewer. Clearing private wastewater pipes is licensed work, and a plumber’s CCTV camera pinpoints the cause.

Is drain acid safe to use at home?

Drain acid is the most dangerous drain product you can buy. It can cause severe burns, gives off fumes, reacts violently with other cleaners and can damage fixtures. If you use any chemical, wear gloves and eye protection, ventilate the room and never combine products. For a stubborn blockage, a plumber is the safer option.

Getting a blocked drain cleared in Sydney

If you’ve tried to unclog a drain with the grate, plunger and hot water and it still won’t clear, the problem is in your pipes rather than the fixture. TQN Plumber’s licensed Sydney plumbers clear blocked drains, find the cause with CCTV and fix it so it stays clear. We give you an itemised quote before any work starts. Book a blocked drain plumber.

Related guides

• How to clean a shower drain
• How to unclog a kitchen or bathroom sink
• Blocked stormwater drain: causes and fixes
• Blocked sewer drain: signs and solutions
• Hydro jet drain cleaning explained
• Bathroom drain smell: causes and fixes
• How to get rid of drain flies
• Cleaning drains with baking soda and vinegar