Blocked Drains: How to Clear Blockages and Resolve the Underlying Cause

It’s easy to take your plumbing for granted until it stops…

Blocked drains are among the most common and disruptive maintenance issues homeowners face. Understanding what to look for, how to prevent them and who to call can provide peace of mind and help prevent minor problems from becoming major headaches.

With over 40 years of experience as maintenance and emergency plumbers, we’ve encountered blocked drains of all shapes and sizes. In this comprehensive guide, we’ll help you identify the common causes of blocked drains, offer some DIY fixes you can try, and explain the short, medium, and long-term solutions a professional plumber can provide.

If you’re experiencing a blocked drain in Brisbane, our expert team is ready to help. Call us today at (07) 3878 4444 or visit our Blocked Drain service page for prompt and professional assistance.

What Are the Different Types of Drains?

Before we get into how to clear blocked drains, let’s quickly explore the different types of drains you have on your property.

Sewer Drains

Most people think of a sewer system when they hear the word “drain.” Sewer drains connect toilets, bathrooms, kitchens, and laundries, carrying wastewater into a sewer main. In Brisbane, the mains connection is managed by Urban Utilities (QUU) and leads to a sewer treatment plant.

An example of a Brisbane City Council Drainage Plan for a domestic property with a kitchen, laundry, and bathroom.

Stormwater Drains

Stormwater drains remove rainwater from your roof and gutters via downpipes and surface drains (such as pits and strip drains). This water is directed to the street or council stormwater line and eventually runs into creeks, waterways, and reservoirs.

A blocked stormwater pit. This pit is designed to collect surface water during heavy rainfall events.

Warning Signs Your Drain May Be Blocked

Early detection of a blocked drain can save you from a plumbing nightmare. Keep an eye out for these common warning signs:

• Slow Drainage: If water takes longer than usual to drain from sinks, bathtubs, or showers, it may indicate a blockage.
• Gurgling Sounds: Strange gurgling noises when water drains often indicate that air is trapped in the pipes due to a partial blockage.
• Foul Odors: Partially blocked drains can create unpleasant smells, often due to trapped debris or buildup.

If you notice any of these signs, it’s essential to take action promptly to prevent the blockage from worsening.

Common Causes of Blocked Drains

Understanding what causes blocked drains is the first step in preventing them. Here are the most common culprits:

External Drains (Sewer or Stormwater)

• Tree Roots: Roots can invade damaged or cracked pipes, leading to blockages and significant damage.
• Leaves and Debris: Leaves, dirt, and other debris can clog outdoor drains, especially after heavy rain or storms.
• Back-falling or Broken Drains: Ground movement or old earthenware clay pipes in poor condition can cause drains to back-fall or break.

Kitchen and Bathroom Drains (Sewer)

• Grease and Oils: Cooking fats and oils can solidify in pipes, causing blockages in kitchen sinks.
• Food Scraps: Small bits of food can accumulate over time, leading to slow drainage or clogs.
• Hair: Hair strands can tangle together, forming clumps that block water flow in showers, bathtubs, and vanity basin drains.
• Soap and Hygiene Products: Soap scum and remnants of toiletries can build up inside pipes, leading to partial or full blockages.
• Debris and Foreign Objects: We’ve encountered everything from children’s toys to chopsticks and tennis balls lodged in drains. These foreign objects can cause significant blockages.

Why you should never try to wash a chopstick down the drain!

DIY Methods to Clear a Blocked Drain

If you’re dealing with a minor blockage, there are some simple methods you can try before calling a professional plumber. These approaches can often resolve common blockages and help restore proper drainage:

Plunging

• When to Use: Plunging is effective for clearing minor blockages in sinks, toilets, and showers. It’s particularly useful for blockages caused by excess toilet paper or food waste.
• How to Do It: Place a plunger over the drain opening, ensuring there’s enough water to cover the plunger’s head to create a strong seal. Press down and pull up on the plunger handle vigorously to create suction and dislodge the blockage. Repeat several times until the water drains freely.

 Hot Water and Detergent

• When to Use: This method is especially effective for grease-related blockages commonly found in kitchen sinks, as the hot water and detergent help dissolve built-up fats and oils.
• How to Do It: Boil a kettle or pot of water. Mix a small amount of detergent and pour the mixture down the drain. Let it sit for a few minutes to dissolve grease and debris, then flush the drain with another pot of boiling water to clear out any remaining residue. This can be repeated multiple times.

Drain Cleaning Fluids (Use With Caution)

• When to Use: Use chemical drain cleaners as a last resort and with extreme care, especially if natural methods don’t work. Consider more environmentally friendly options first.
• Caution: Chemical cleaners can corrode pipes and are harmful if mishandled. Always follow the manufacturer’s instructions and use protective gear.

How Professionals Clear Blocked Drains

If DIY methods haven’t cleared the blockage or you have a major blockage, it’s time to call a professional plumber. Depending on the type of blockage and its severity, professionals use various methods including:

Manual Cleaning:

Plumbers might use specialised plungers, hand rods, hot water with detergent, or heavy-duty drain cleaning fluids to clear blockages.

Electric Drain Cleaning (Drain Snake):

This mechanical method uses a motorised drain snake to tackle more challenging blockages, such as those caused by tree roots or large debris. It is a very common and effective way of clearing external drains.

Our team using a drain cleaning machine to clear a tree root blockage at a set of units in Paddington in Brisbane.

Jet Rodding (High-Pressure Water Jet):

This technique uses a high-pressure water jet to clear stubborn blockages, including tree roots and grease build-ups. Jet rodding is very effective for many types of blockages, such as clearing sludge from back-falling drains and removing heavy root intrusion.

Note: The information below about clearing a blocked drain is from the Master Plumbers Association of Queensland (MPAQ). Keep in mind that clearing the drain does not mean the underlying issue has been resolved. More on this later

Investigating The Root Cause of Blocked Drains

If your drain blockage is severe or recurring, there may be an underlying cause that requires attention. Identifying and addressing this root cause is crucial to preventing future blockages and keeping your plumbing system flowing freely. However, further investigation often involves specialised equipment and can be time-consuming, so it’s best to discuss with a plumber when these steps are both practical and cost-effective.

If the blockage requires investigation, the next step is a CCTV drain inspection to thoroughly examine the condition of your pipes. This inspection uses a specialised, flexible camera inserted into the drain to provide a view of the interior of your pipes. With this, plumbers can identify the cause and location of the blockage—whether it’s tree roots invading the line, accumulated debris, or structural damage. They can also use locating equipment to record the approximate position and depth of any issues. This information is essential for planning the most effective repair solutions to address the root cause and prevent future blockages.

A screenshot from one of our drainage specialists’ CCTV camera inspection showing a collapsed drain with tree root ingress.

Treating The Root Cause of Blocked Drains

(Short-Medium and Long Term Solutions)

Once the root cause of a blocked drain is identified and located it’s possible to recommend an appropriate solution. Depending on the severity and nature of the problem, the recommendation will likely include one of the below options.

Pipe Replacement (Long Term Solution)

When pipes are extensively damaged or collapsed, excavation may be necessary to remove and replace the affected sections of pipe.

• Benefits: It completely removes damaged pipes and upgrades them, typically to PVC. This provides the most reliable long-term solution.
• Ideal For Damaged pipes due to extensive root intrusion or ground movement.
• Disadvantages: Pipe replacement can be costly and time-consuming depending on the depth, size, and location of the break. Excavation can also impact other services, and landscaping which may need restoration after the repair.

Pipe Relining (Medium-Long Term Solution)

Pipe relining is a trenchless repair method that reinforces existing pipes without the need for extensive excavation. A lining is inserted into the damaged pipe, which then hardens to form a new smooth surface inside the old pipe.

• Benefits: Minimally invasive and preserves landscaping or structures above ground. It can seal cracks and prevent root intrusion.
• Ideal For: Pipes with cracks, leaks, or minor structural issues, especially when access is difficult, such as under concrete slabs or within service ducts.
• Considerations: While this method avoids digging, it can still be relatively costly and time-consuming depending on the pipe’s length and the extent of the damage. It’s important to ensure the pipes are suitable for relining and that any collapsed sections are addressed first.

Routine Maintenance and Drain Cleaning (Short-Medium Term Solution)

Regular maintenance can be an effective way to keep drains functional and prevent them from escalating into a major issue. Scheduling periodic drain cleaning helps remove the buildup of grease, debris, and other materials that can lead to blockages.

• Benefits: Reduces the risk of unexpected blockages.
• Ideal For: Homeowners looking for proactive solutions to maintain clear drains, particularly if minor blockages or slow drainage are a recurring issue.
• Considerations: This approach won’t fix underlying structural problems but can keep your drains clear and functional in the short to medium term.

Preventing Future Blockages

Regular maintenance and mindful habits can go a long way in preventing blocked drains. Here are some practical tips to help keep your drains clear:

1. Mind What You Flush

• Follow the “3 Ps” Rule: Only flush Pee, Poo, and toilet Paper.
• Avoid Flushing Non-Degradable Items: Wipes (even flushable wipes), feminine hygiene products, diapers, cotton swabs, or other items can cause blockages and should never be flushed down the toilet.

Flyer is from Queensland Urban Utilities (QUU) on the 3 P’s.

• Use Sink Strainers: Place strainers or guards in your kitchen sink to catch food particles before they go down the drain and cause blockages.

• Gutter and Outdoor Drain Cleaning: Keep outdoor drains clear of leaves, debris, and other materials that can cause blockages, especially before and after heavy storms.

Over the past 40 years, we’ve seen our fair share of blocked drains. This one may take the cake!

Conclusion

Blocked drains are more than just a nuisance—they can lead to significant plumbing issues if left unaddressed. You can keep your plumbing system flowing freely by understanding the common causes, recognising early signs, attempting some DIY fixes when appropriate, and knowing when to call in the professionals.

Need Professional Help?

Don’t let a blocked drain disrupt your life. Our expert team in Brisbane is ready to provide fast, effective, and affordable blocked drain solutions.
• Call Us: (07) 3878 4444
• Same-Day Service: We attend 99% of jobs the same day!
• Guaranteed Work: All our work is 100% guaranteed.
• Expert Advice: Our experienced team offers honest advice at great prices.
If you’re experiencing a blocked drain in Brisbane, call us today or visit our Blocked Drain service page for prompt and professional assistance.

Image: A water hammer arrestor installed near a washing machine. This was installed as a last resort and provided some temporary relief by reducing the severity of the water hammer.