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10 tips for clearing blocked drains

One small, smelly blocked drain can become a big headache, causing substantial damage to your home. It can also become a major inconvenience for you and your family.

Blocked drains are a recurring problem for homeowners. To ensure free-flowing drains, learn how to pinpoint the blockage, identify potential issues, and take action with the aid of a plumber.

Curran Plumbing’s expert technicians have prepared the following tips for homeowners.

Signs of a Blocked Drain

The signs of a blocked drain can creep up slowly or overpower immediately – either way: take action if you spot the following red flags.


A stinky sink or drain hole indicates that household waste matter – including paper, fat and hair – has clogged the drainpipe. While it festers it blocks the water flow, causing a bad smell.


An overflowing toilet should really trigger alarm bells since a blockage could potentially send raw sewage out of the toilet bowl and into your home. Even with clean water, overflows in sinks cause extensive household damage. From a safe distance, check outdoor drains and manholes for overflow signs to report to a plumber.

Gurgling sounds

As water tries to flow around a local blockage in the drains there will be odd gurgles and other strangulated sounds coming from pipes, sinks and showers, indicating trapped air. Noises near bathtubs or showers may signify a blockage further down the line.

Slow to drain

If water in sinks, showers, baths and toilet bowls is slow to empty, pools or forms bubbles and backwash a blockage is obstructing the flow. If several fixtures are affected, for example the water level changes in the basin as well as the toilet bowl upon flushing, it suggests the blockage is located down the main sewer drain.

Causes of Blocked Drains

There are some common reasons that drains get blocked. Secure your home by avoiding these common blocked drain culprits:

Tree roots

Be aware when tending and planning your garden that roots from plants and trees breaking into hairline cracks in older pipes are the number one cause of damage. This is even more likely during a long dry spell when plants are looking for a water source. Old clay pipes are also particularly vulnerable to tree root damage.


Wipes, tissues, sanitary products and excess loo paper can cause severe blockages. When sanitary products are placed in the toilet they expand, causing major drainpipe issues. While some wipe packaging indicates they can be flushed this isn’t the case – for example, Sydney Water reports that 75% of sewer blockages involve flushed wet wipes.

Foreign objects

Start the lesson early: Kids’ toys should stay out of the toilet – for obvious reasons of hygiene as well as the expensive blockages they can form.

Cooking oil

If kitchen oil, fat and grease have been tipped down the sink they can coat pipes and harden into obstructions in the cold. Down the sewer line, the oil, grease and fat can form enormous ‘fatbergs’.

Food scraps

Food waste can block sinks, even with a garbage disposal device. It’s also handy to remember that coffee grounds and tea leaves don’t break down and they can cause a serious blockage.

Mineral build-up

Descale regularly or install a water softener in hard water areas to prevent mineral build-ups like limescale or calcium constricting pipes and encouraging blockages.


Soap bars are made with fats and oils and soap bar scum can thicken inside drains and bind dirt and items into a clump. Look for soap-free alternatives that don’t contain fats and oils.


Regular shampooing will result in some hair loss that can clog drains in bathtubs and showers. If you wash your dog in the bath its hair can also end up blocking drains and pipes.

Natural Debris

Garden grills and gutters fill up with leaves, soil and other natural matter, especially during heavy rains and autumnal leaf drops. Uncleared debris blocks up gutters, drains and drainpipes.

Cat litter

As kitty litter is designed to clump and absorb moisture the last place you want it in your drains, so never put it down the toilet.

How to Clear a Blocked Drain

Here are some tips for minor drain clogs at home, but call in a professional plumber for stubborn blockages.

boiling water down sink

1. Boiling Water

A straightforward non-toxic option is to carefully clean sink holes, drain holes and toilet bowls with boiling water. Avoid the sink seal. Boiling water breaks down grease, soap and food that binds objects into a clump and loosens blockages. Mix with detergent for tackling grease. Choose hot water rather than boiling water if you have PVC pipes

2. Natural drain cleaners

A great household non-toxic solution is the combo of bicarbonate of soda (baking soda) and white vinegar, reacting together to clean grease and break down solids. Flush drains with hot water afterwards to remove any residue. Also try commercial kind-to-earth cleaning fluids, such as bacteria-based enzyme cleaners. This solution won’t help with plastic objects or tree roots.

3. Caustic cleaners

They aren’t friends of the environment but commercial caustic cleaners, when used carefully, can dissolve tougher items like hair, as well as grease. Protect your hands and wear a mask, leave in chemicals for the recommended time and flush pipes with cold water afterwards to reduce chemical residue (hot water might react).  Caustic cleaners aren’t suitable for PVC pipes, older pipes and some pipe glues.

4. Plunger

Cup plungers are a practical non-chemical de-clogger of sinks. First cover the overflow drain with tape or a damp cloth to create a seal. For sufficient pressure in a double sink, seal the second drain. Pressing a plunger up and down over a drainage hole will create an air-based force that can shift obstructions. Even squeezing an empty milk carton over the sinkhole can create a jet of air. Use a flange or toilet plunger for clearing loos. Grease and mineral remnants don’t respond as well to plunging so may require another option.

5. DIY drain snake

From a coat-hanger, fashion your own version of a plumber’s snake to scrape away at minor close-by blockages, including hair or soap.  Or, buy a drain auger, a handheld version of the plumber’s snake.

6. Plumber’s drain snake

The ‘Eel’ or plumber’s snake can remove blockages near the drain opening. The tool has a sharp-tipped coil at the end of a cable and cuts away at blockages when it spins. It has a longer range than a handheld drain auger and benefits from being operated by a plumber.

7. CCTV drain inspection camera

CCTV drain inspection cameras are a great plumber’s tool to verify cracked and obstructed pipes. The camera is attached to a cable reel and guided through pipes providing a real-time inspection and identification of the problem.

8. High Pressure Water Jet

Hydro jets or high pressure water jets can move even the toughest blockages along. Plumbers should operate the equipment as the force is very strong. The water pressure from the water jet can blast tree roots and blockages out of the way.

9. Excavation

A severe blockage may require a plumber to dig out the area around the pipe, remove blockages, repair damage then replace the pipe and backfill. Old clay pipes can crack and collapse and the entire pipe may need to be dug up and replaced to clear the blockage.

10. Pipe Relining

A professional plumber can reline existing older pipes economically with an epoxy resin that hardens to make the pipeline watertight and resistant to tree roots that cause flooding or backed-up sinks and toilets. Before the relining, the plumber will employ CCTV and water jets to locate and clean out blockages. ‘No Dig’ pipe relining is an increasingly popular option for people who wish to repair their pipes without damaging their gardens.


Professional plumbers can advise on blocked drain fixes and future-proofing solutions. Call Curran Plumbing for drainage advice including services such as ‘No dig pipe relining’, on 1300 781 891. 

Need a plumber? Call Curran.