Underground drains are a part of our guttering system we rarely tend to think about, as they’re safely out of sight.

And yet their overall role is absolutely huge!

Unfortunately, most of us realise that vital role only when something goes wrong, and our drainage pipe is blocked – which will inevitably happen sooner or later.

No need to worry, though!

If you’re wondering ‘how do you clear outdoor drain pipes’, you’ve come to the right place!

At Drainage Superstore, we’ll show you exactly how to unclog an underground outdoor drainage pipe – and not just one way but six!

Read on.

Table of contents:

How do I know if my underground drain is clogged?

First things first:

What are the tell-tale signs that your underground drainage is clogged?

To begin with, you might start noticing damp patches in your basement. If wastewater can’t make its way to the sewer due to blockage, it’s likely to end up there, causing a fair amount of damage, such as mouldy surfaces or even structural damage to the walls or floor.

In addition, keep an eye on your downpipes and gutters during periods of intense rainfall. Is water pooling there or even overflowing?

If the answer is a resounding yes, chances are you’re dealing with a blocked soil pipe underground. And while an overflowing gutter might not sound like a big deal, over time this might lead to corrosion to both the gutters and the fascia.

So now, it’s time to get to work and fix the issue!

How to unblock your outside drain

Start by finding the blockage. This can be a bit tricky, but you should bear in mind that most clogs tend to occur at transition points or in elbows – so, make sure you check there first.

Provided you’ve found the problem area, you’ve got a few options you can choose from.

Let’s take a closer look at each one in turn.

Use a drain snake

A drain snake is the professional plumber’s go-to drain unblock tool, which does an excellent job of removing clogs in both an indoor and an outdoor drain pipe.

The process of unblocking drains with rods is variously called snaking, cable rodding, augering or rooting. It involves pushing a specialist, heavy-duty metal cable through the pipe to break up the blockage, thus allowing water to flow through.

But how do you unclog a drain pipe without a snake?

Check this out:

Use a drain bladder/ball bag

A drain bladder, also known as a ball bag, is yet another highly effective outside drain unblocker professionals love to use. Essentially, this device is a deflated balloon produced from heavy-duty rubber. After it’s filled with water, the bladder will deliver a huge flow through the pipe, breaking up and flushing away the clog.

A ball bag has to be used carefully, though – and we wouldn’t recommend it if you have old pipes, as the high pressure might cause more harm than good.


Hydro jetting

Hydro jetting is one of the more innovative solutions to blocked pipes.

To put it simply:

You use a high-pressure hose to blast through the blockage and clear it. Then, you pull out the hose slowly and carefully and voila – the clog is gone!

Water jetting

Water jetting is a similar process to hydro jetting.

Here’s the thing:

You’ll insert a water hose into the pipe in question, delivering a high-pressure blast of water, getting rid of oil particles, grease and debris. The only slight drawback of water jetting is that it’s not nearly as effective if your pipework is longer than 100 metres.

Use a Picote milling machine

Think of the Picote milling machine as an upgrade on the drain snake. This amazing high-torque device features specialist heads at the end of a cable to remove stubborn roots, accumulated soil and heavier debris and sediment.

A Picote milling machine can be extremely useful in a wide range of applications, but it can also be somewhat expensive.

Having said that:

There’s one way to unblock house underground drainage which is virtually free.

Here’s the deal:

Use baking soda & vinegar

The classic combination of bicarbonate of soda and vinegar is a tried and tested solution for unblocking household drains.

Basically, what you do is pour bicarb into the drain, followed by plenty of white vinegar. You’ll hear a mighty whooshing sound as a result of the resulting chemical reaction which will create plenty of bubbles and hopefully unclog the drain. Once the bubbles are gone, simply pour a large quantity of hot water down the drain.

Keep in mind that the usefulness of this method can be a bit limited when dealing with a bigger downpipe blocked underground.

Still, you can always give it a shot – and if this method doesn’t work, you have plenty of other options.

We wouldn’t recommend using a heavy chemical to unblock drains, though, as it will damage the pipes.

As a last resort, you can always call a professional plumber.

Knowing when to call the professionals

While there’s plenty you can do to unblock a clogged drainpipe, there are some occasions when it’s best to let the professionals do the heavy lifting.

Here are a few of those instances:

⛔ There are large moss or mildew accumulations around the pipes.
⛔ The seams of the pipework are experiencing stress.
⛔ The joints of the downpipes are leaking.
⛔ The pipework is cracking.

If you notice any of these warning signs, stop! It’s time to give your friendly neighbourhood plumber a bell instead of trying to fix things yourself.

How to avoid getting a blocked gutter drain like a pro

When it comes to cleaning your underground drainage, prevention is better than cure.

The good news is:

There’s plenty you can do to prevent clogs from blocking your pipes!

Firstly, you can buy enzyme cleaners. These liquids contain natural bacteria which work hard to break down organic materials naturally, keeping your pipework nice and clean.

Secondly, you can install a downpipe strainer. That’s a cheap, easy way to prevent leaves, dirt and debris from finding their way into your underground drain pipes.

Thirdly, you can invest in leaf guards. As their name suggests, these handy devices will stop leaves and branches from entering your gutters and, ultimately, your underground drainage.

You can even do all of the above!

And on that note…

Final thoughts

A drainage pipe getting blocked is one of those things that inevitably happen if you live in the same house long enough simply due to the heavy traffic and accompanying wear and tear.

Luckily, there’s plenty in terms of both prevention and cure you can do to ensure it doesn’t cause a massive headache and damage your underground drainage system beyond repair.

The question, as the famous Russian futurist poet Vladimir Mayakovsky put it ever so eloquently, is:

‘But could you play right to the finish a nocturne on a drainpipe flute?’

Well, now that you know exactly how to unclog an underground outdoor drainage pipe in six different ways, you just might be able to!

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