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How to clear a blocked outside drain

A blocked outdoor drain can be a big source of worry for any homeowner, especially if there is rain or storms on the horizon. A simple blocked drain can turn into a nightmare for a homeowner, with flooding or other issues impacting your home. Make sure if you find a blocked or slow running drain you deal with it as soon as possible, you do not want to find out too late that parts of your house are flooded.

In fact, outside drains need to be regularly cleaned to prevent issues, as over time it is impossible to prevent small debris and dirt from flowing into the pipe. Regularly checking and clearing out your outside drains can prevent the need for expensive repairs that blocked drains can cause to your home.


There are a few simple steps you can try at home if you get a blocked outdoor drain to try and remove the source of the blockage yourself before you need to call in the professionals. Have a look at the list below for some easy steps to try yourself.

Verify the source of the blockage

It is important to first try to figure out what the blockage could be. Most drains would have a grate to filter our debris, however sometimes the grate does not prevent all the rubbish from flowing through and clogging the drain. The usual suspects for outdoor stormwater drains are leaves, sticks or mud. Outdoor showers could be clogged up with hair, and for gutters and downspouts the culprits tend to be leaves or small sticks.

Clear out by hand

Make sure you first put on a pair of long gloves to protect your hands and arms and carefully reach into the drain and remove anything you find by hand. Make sure you search around as some drains can be multidirectional and branch off in different directions. These bends or corners can be an easy way for debris to get caught so check around the edges of the pipe to ensure you have removed all you can.

If the source of the blockage is too far down for you to reach, there are several other options you can look at.

Drain Snake or Drain Auger

A drain snake or drain auger can be bought at any hardware store. It is a long, flexible cable that has a short coil on the end. You insert the coil end into the drain and feed the cable through until you feed resistance, which will be the source of the blockage. If you carefully rotate, the coil on the end of the drain snake will catch the debris and allow you to pull it back through the pipe and remove it.

Drain Rod

Similar to a drain snake, but straight instead of a cable. These can be easier to use than a drain snake as long as the pipe is relatively straight. You can also buy a number of different brushes or scraping tools which can be attached to the end that can make this tool work for both clearing out any blockages, and also will make general pipe cleaning and maintenance much easier.

Water and Bleach

Water and bleach are a potent combination to clear out any debris. You can use your hose to spray down the pipe, taking care to hit the sides with as much force as possible to clean out the drain and try to break down any debris. Adding 1-2 cups of bleach can both help breakdown any additional smaller blockages and also kill any bacteria that could be causing unpleasant odours because of the blockage.

Another option if you have a large bucket is to use boiling water instead of the hose. The additional heat can help breakdown any rubbish faster and is especially effective if any grease or similar debris has gone down the drain. You can add the bleach directly into the hot water or add it as a middle step between buckets of hot water.

Bicarb (baking soda) and Vinegar

This is definitely an either/or solution as you cannot do this at the same time as the water and bleach option. Mixing bleach and vinegar creates an extremely dangerous chemical reaction, so you can choose to use water and bleach or baking soda and vinegar, never both in the same pipe at the same time.

Get some baking soda from your kitchen and pour a cup down inside the drain. Depending on the width of the drain you may need more, you can normally buy large boxes from hardware retailers or even the grocery store. Immediately follow the baking soda with a cup or more of vinegar. The two items will react, fizzing up and clearing your drain. Let it sit for at least an hour, then wash through with the hose on high to guarantee the drain is clear.

High Pressure Hose

One last option you can try is a high-pressure hose, or water jet. High pressure hoses or water jets can be bought from hardware stores, and even rented for the day. While using a high-pressure hose is extremely effective at cleaning outside drains and pipes, you do need to be careful as the pressure from the water can damage your pipes. You can ask for advice where you purchase or rent your high-pressure hose or water jet on the correct water pressure to use, depending on the material your pipe or drain is made from. However, with the right settings, high pressure hoses are a versatile and eco-friendly method of cleaning out the most stubborn of blockages. As it uses only water and pressure, there are no chemicals being added to the environment. They can also have flexible cables which let you feed it down the pipe for a certain length, which will let you reach any blockages that are a little out of reach.