How To Unblock Drains Outside (And When You Need A Plumber)

Are you dealing with a soggy patch of lawn? A smelly puddle near your house? Water pooling near your outdoor grates? You’re probably asking yourself how to unblock drains outside.

It’s actually one of the most common plumbing issues Brisbane homeowners face – and while some blockages can be dealt with using DIY methods, others are best (and sometimes legally required) to be handled by a fully-licensed plumber.

So let’s unpack:

• What’s going on with your outside drains
• What you can legally do yourself in Queensland
• And how professionals actually go about clearing underground outdoor drains.

Signs you’ve got a blocked underground drain

As you probably already know, underground drains are designed to carry wastewater away from your home efficiently and safely. However, they can become blocked by things like tree roots, fat build-up, silt, debris, and broken pipes.

You’ll usually know something’s wrong when you notice:

• An outside drain overflowing during rain or after a shower
• Slow drainage from toilets or kitchen sinks
• Bubbling or gurgling sounds in outdoor grates
• Foul smells coming from outside near your drain area.

Once you see the signs, you can’t un-see them! It’s then time to figure out whether it’s safe and legal to attempt a DIY fix – or whether you need to call a pro.

Can I unblock my own outdoor drain in Queensland?

First, the good news. In Queensland, minor maintenance – such as plunging or using a drain snake on a visible grate or gully – can legally be done by a homeowner. But anything involving plumbing work on underground pipes, sewerage systems, or stormwater drains generally requires a licensed plumber under QBCC regulations.

So if you have an outside drain blocked, you can try some safe surface-level techniques. But if that doesn’t work – or if the blockage is deeper – it’s best (and legally necessary) to hand it over to a fully-licensed plumber.

DIY methods that are legal (& sometimes effective)

If you’re confident the blockage is close to the surface, here are a few homeowner-safe things to try:

1. Check for debris at the grate

Remove leaves, mulch, or garden debris from around the outdoor drain opening. Sometimes it’s as simple as that.

2. Try a hose blast

Run a high-pressure garden hose into the drain. It can help dislodge minor blockages or built-up grime.

3. Use a plunger

If you have a blocked kitchen drain outside or similar gully trap access, try using a plunger with strong, even pressure. This works best when there’s standing water above the drain.

4. Blocked outside drain home remedy

Some homeowners swear by pouring boiling water followed by baking soda and vinegar down the drain. It may help with fat and soap scum – but it’s rarely enough for tougher underground blockages.

Just remember, once you’re reaching below ground level or entering a sealed pipe system, you’re not legally allowed to proceed without a plumbing license. That’s when you need to call in the experts.

How plumbers unblock outdoor underground drains

Plumbers use advanced tools and techniques that go far beyond home remedies or hardware store gear. And yes – underground blockages are harder to diagnose and fix because they’re not visible.

Here’s what a professional will do:

1. Inspection with a drain camera

A licensed plumber will often start with a CCTV drain inspection. A camera is fed down the pipe to visually identify the blockage, its location, and what caused it – whether it’s roots, collapsed pipe, grease, or foreign objects.

2. High-pressure water jetting

This is the go-to method for how professionals clear outdoor drain blocked scenarios. A drain jetter blasts extremely pressurised water through the pipe to cut through tree roots, clean pipe walls, and flush out debris – all without digging up your yard.

3. Mechanical augering (If needed)

If the blockage is tough or in older pipes, plumbers might use a rotating mechanical auger. It’s like a powerful version of a hardware store drain snake, capable of cutting through thick obstructions.

4. Pipe repairs or relining

If the problem turns out to be structural (eg. cracked, crushed, or sagging pipes), the plumber may recommend relining the pipe internally or replacing a section. This is especially common with older clay or concrete pipes in Brisbane suburbs.

This kind of work is far beyond DIY – and absolutely must be carried out by a licensed plumbing professional under Queensland law.

Why underground blockages are more difficult

Trying to figure out how to unblock a drain when it’s buried underground is not the same as dealing with an indoor sink. Why?

• You can’t see what’s causing the blockage
• You can’t hear or smell where it is
• The blockage could be anywhere between your house and the street.
• Digging without knowing the pipe’s location risks damaging other services.

Even the best plumbers rely on camera inspections, locators, and years of experience to pinpoint the exact spot.

So when you look up how to unblock drains, it’s important to consider whether the problem is accessible – or needs professional help.

Can blocked drains come back?

Yes! And the blockage can definitely come back if the cause isn’t fully removed. For example, if tree roots are cleared with a jetter but the cracks in the pipe remain, those roots will grow back. That’s why full inspections and long-term solutions are key.

This is also why Brisbane Drain Cleaning offers ongoing maintenance plans and root control programs – not just one-off jetting.

What if the blockage is from the neighbour or council?

If you think the blockage isn’t on your property – for example, if your yard is flooding but your neighbour’s isn’t, or if the gully is filling from downstream – call a plumber first. They’ll determine where the issue lies and can contact the council on your behalf if needed.

Never attempt to dig or unblock council-owned drains yourself – it’s illegal and potentially dangerous.

Final tips on how to clear blocked drains outside

Here’s a quick checklist before you call in the pros:

• Make sure it’s not just leaf or mulch buildup around the grate
• Try a safe flush with hot water or a garden hose
• Don’t use harsh chemicals – they can damage pipes and harm your garden.

Remember to know your limits – if your outside drain is blocked and it’s underground, the best thing you can do is call a pro. If you’re really determined to learn how to clear blocked drains outside yourself, just make sure the information you find is QLD-compliant – or you risk fines and worse damage.

Need your outdoor drain cleared professionally?

If you’re struggling with a blocked outside drain, don’t stress. Brisbane Drain Cleaning has the tools, training, and required licensing to locate, diagnose, and fix any outdoor blockage – fast.

Our friendly Brisbane drain plumbers use the latest in drain jetting and CCTV camera tech to make sure the problem is fixed at the root – not just patched up. Learning how to unblock outside drain pipes properly takes years of training and on-the-job know-how, so

Call Brisbane Drain Cleaning today. We’ll take care of your underground drain issues the right way – safely, legally, and efficiently.