How To Unblock An Outside Drain

Blocked drains can be a big frustration for homeowners, causing foul smells and even flooding in your garden. Blockages are more common in the narrower pipes inside your home, however, debris can easily build up within outside drains as well, leading to some nasty blockages. 

While outdoor drain blockages can be a little harder to solve than a blocked sink, fixing the problem isn’t as hard as you might think. There are steps you can take to resolve the problem and clear the blockage to get your drains back in working order in no time. All you need is the right tools and knowledge. To give you a helping hand, we’ve put together a simple guide on how to unblock a drain outside.

Table of Contents

Why Is My Outside Drain Blocked?

Most blockages in drains are caused by people putting things down their drains that they shouldn’t. In the kitchen, this tends to be grease and fat, food debris, coffee grounds and bits of paper and cardboard packaging. In the bathroom, soap scum and hair clogs are notorious for causing blockages in sinks and shower drains, while flushed wipes, excessive toilet paper and sanitary products can easily block up the pipes. 

All of these things can cause problems to your outside drains too. After all, they are all going down the same pipes. In addition, outdoor debris, such as leaves, soil and mud, litter and branches can all cause blockages to form, especially after bad weather. 

Is Your Inside Drain Blocked?

If you have a problem with a clog or blockage in one of your inside drains, such as the kitchen sink or the shower drain, then there is a good chance you can unblock it yourself. Common causes of blockages in your kitchen is the build-up of fat and grease in your kitchen sink. Take a look at our article on How To Unlock A Sink for some DIY guidance. 

If your shower isn’t draining well then it is likely a hair clog or clumps of soap scum causing a blockage in your shower drain. Our article, How To Unblock A Shower Drain has plenty of advice on how to clear any blockages in your shower drain pipe easily and effectively. 

If it is your toilet that is blocked, it is always best to attempt a few common DIY toilet unblocking methods, before attempting to clear any toilet drains outside. Our article, How To Unblock A Toilet has a number of effective DIY methods that can fix a blocked toilet, including ones with or without a plunger.

Who Is Responsible For Fixing Outside Drainage Issues?

Before attempting to unblock an outside drain it is important that you establish who is responsible for clearing the blockage. Who is responsible for blocked outside drains will often depend on how the drainage system is set up. In many cases, the responsibility lies with local sewerage companies to ensure clear ownership and a more efficient and effective maintenance system. 

The public sewer and lateral drains will always be the responsibility of the sewerage or water company. However, any private drains within the boundary of your property will be the responsibility of the homeowner and will be up to you to take care of. 

However, it is possible that you have a shared drain, such as a lateral drain that you share with your neighbours that’s blocked, then you may not be on your own with this issue. In this case, you will need to contact your local water company.

How Do I Know If My Drain Is Shared?

To find out if your outside drains are shared, contact your water sewerage company. You can also get in touch with your local authority for more information. 

How To Unblock A Drain Outside

Once you have confirmed that the drain is your responsibility then you can go ahead and attempt to unblock it yourself or call out a professional plumber for help. If the drain is outside of your property, then simply contact your local water sewerage company so they can take care of the blockage. 

There are steps you can take to fix a blocked outside drain yourself, as long as the problem isn’t too serious and the drain isn’t shared with your neighbours. If you are at all in any doubt, it is always better to be safe than sorry and get in touch with a professional who will have the tools and experience to take care of any problem quickly and effectively.

What You Will Need To Unblock An Outside Drain

You will need a few key items to tackle an outside drain, and it is best to gather them in advance before making a start. 

  • Rubber gloves, preferably long sleeve ones. 

  • Protective clothing, goggles and a face covering.

  • A drain rod (a bigger version of a plumber’s auger or drain snake, often found in hardware stores). 

  • A screwdriver.

  • A bucket and some bin bags.

  • Garden hose, preferably a pressure hose.

What You Will Need To Unblock An Outside Drain

Finding Where The Drain Is Blocked

The first step to unblocking any drain is to identify and locate where the blockage is. To do this, check the water levels in the drain chambers. Simply take off the drain cover and look inside. If it is full of water, then the blockage is after that drain chamber. On the other hand, if the chamber is empty, then the blockage will be upstream of that chamber. Use this to narrow down the location of the blockage, which will be in between a full and empty drain chamber. 

Remove The Drain Cover

You may need to use your screwdriver for this part. Simply use the screwdriver to pry the drain cover off, be careful not to let the cover fall into the drain. If it is particularly heavy, or the screwdriver isn’t working, try rowing a rope around the cover to get better leverage. 

Start Removing The Blockage By Hand

With your gloves, face mask, goggles and protective clothing start to remove as much of the blockage by hand as you can if you can reach it. The more you remove now, the easier it will be to clear the blockage with the drain rod. Use your bucket or bin bags to gather up the debris, so you can dispose of it later. 

Use The Drain Rod

Feed the drain rod into the drain and twist the rod into the blockage. The narrow metal should slide through the sludge. Be sure to twist it in a clockwise direction, as twisting it anti-clockwise could cause the joints of your rod to unscrew. Apply some pressure and keep plunging and twisting, it may take some time to get through the blockage, especially if the blockage is stubborn. Move the rod around to try and break apart the blockage as much as possible. If it starts to feel easier, it is a good sign that the blockage is starting to clear. 

Use The Drain Rod

What If There Is Standing Water?

If there is standing water caused by the blockage in your external drain then you will need to remove as much of it as possible by using your bucket before attempting to remove some of the blockage debris by hand. 

How To Clear A Drain Blockage With Caustic Soda

You can also use an outside drain unblocker like caustic soda to clear your blockage. Caustic soda is easily found in stores and is a low priced solution. Caustic soda is a very corrosive chemical that reacts vigorously with hair, dirt and food debris. The vigorous chemical reaction will dissolve the debris, clearing the blockage quickly and effectively. 

simply dilute cups of caustic soda in a large bucket of cold water before pouring the solution into the blocked outside drain. After a few minutes, the debris should rise to the top, allowing you to remove the debris from the pipe. Then simply clean the drain with a pressure hose. 

What If I’m Trying To Unblock A Outside Drainpipe?

Unblocking an external drainpipe is the same process you would use to unblock a drain blockage inside your home. 

Start by pouring hot water down the drain. Don’t use boiling water as this could damage or warp your pipes. Either wait a few minutes after boiling a kettle or stop it before it completely boils. 

Then, add a cup of baking soda or bicarbonate of soda to the drainpipe. Wait five to ten minutes, then follow up with a cup of white vinegar. The addition of white vinegar will cause a chemical reaction that will fizz and froth. This will cause the blockage to become dislodged. 

Leave the reaction to do its work for as long as possible, before following up with another kettle’s worth of hot water. If this hasn’t worked, try repeating the process.  

What To Do After Unblocking A Drain?

Once you have successfully removed the blockage and restored a regular flow of water, it is worth spending some time giving your outside drain a good clean with a pressure hose. Clear away any excess debris that has built up around the drain to dislodge any leftover bits of the blockage and help to prevent future build-ups. A regular clean up of your outdoor drains will help prevent any future blockages from occurring. 

Preventing Blocked Drains

It is important to keep your outside drains clear to prevent any future blockages from occurring. However, the best way of preventing your drains from becoming blocked is to control what goes down them. Similarly to your inside drains, your outside drains can become easily blocked and clogged by the build-up of cooking grease and fat, sanitary products, food debris and pieces of plastic and paper. 

In addition, the addition of grates and filters that prevent garden debris, like leaves and branches, from falling into your drains and causing blockages are very effective at preventing blockages in your outside drains. 

Can’t Clear The Blockage? - Call In The Professionals

Outside drain blockages tend to be more complex than blockages in your kitchen sink, which can often leave you unable to clear the blockage with common DIY methods. If this is the case, it is always better to call in a professional to help, rather than attempting more extreme techniques that could cause more harm than good. 

Here at VHL, we provide a drain cleaning and unblocking service in the Greater London area, that includes unblocking clogged drains, high-pressure drain jetting and drain cleaning. Our team of professional plumbers and drain cleaners are drainage experts and will be able to quickly and efficiently identify the problem and apply the right solution to get your drains back to normal in no time. Get in touch with us by phone on 020 3918 6405 or Book Online to arrange a call out and same-day quote.