Blocked drains can cause serious problems for homeowners, potentially leading to foul smells, flooding, structural damage and a build-up of nasty bacteria in the areas surrounding the blockage if unresolved.

If a drain is within the boundary of your property, it is your responsibility – rather than that of your local water company – to ensure it is well maintained and repaired.

But how do you deal with the issue if a drain outside your property becomes blocked? We have put together this guide to help you get a better understanding of your properties exterior drainage system as well as the best course of action should you be faced with the unfortunate circumstance of a blocked outside drain. 

What is outside drainage?

Before understanding how best to solve the problem of a blocked outside drain, it is first important to understand as much as possible about your property’s exterior drainage infrastructure.

That is because the potential fixes for a blocked drain will often change depending on the elements of the system affected. If you want to identify the source of a blockage, you first need to know what you are looking at. 

Let’s take a look at some of the most common elements of a property’s exterior drainage system…

Manhole chambers

Also known as an inspection chamber, a manhole chamber is a point of access for the underground drainage system, so that drains can be inspected and cleaned whenever required.

They can typically be found in three locations in the drainage system:

• Where a main drainage run meets a branch pipe
• Where a drain changes direction horizontally by more than 30 degrees
• Where there is a straight run of piping that is over 22 metres long

Rainwater pipes (downspouts)

Rainwater pipes, also known as ‘downspouts’, are part of the roof drainage system that carries rainwater from a rain gutter on a property.

Rain gutters are the half-pipes found beneath a property’s roofing, designed to prevent water seeping into the property by channelling the rainwater away from the exterior walls and into downpipes.

These gutters are connected to vertical rainwater pipes, which run down the length of a property to ground level, where the water is piped into a surface water drain.

Surface water drains

Surface water drains are the element of the drainage system that collects surface water, i.e. rainwater and melted snow and ice, from various parts of your property and transports it into the sewer network – specifically surface water sewers. The surface water is then put back into rivers and the sea.

These kinds of drain, usually covered by a grid, are typically located at the base of rainwater pipes or in paved areas, such as driveways, around the property.

Foul water drains

Foul water drains carry foul sewage – often referred to as wastewater – from toilets, sinks, showers and baths, and from household appliances such as dishwashers and washing machines.

The foul sewage is then taken to a wastewater treatment facility via foul water sewers, which are kept separate to surface water sewers.

Soil vent pipes (SVPs)

Also called a soil stack or drain-waste-vent (WV), a soil vent pipe (SVP) carries foul waste (sewage) from a property into the underground sewer network. It extends up to roof level to allow sewage smells to release into the atmosphere. SVPs are usually fitted externally, but can also be installed within the wall cavity.

Combined drains

If your home was built during the Victorian era, it could be that you have a combined drainage system that has one set of drains taking both surface water and foul water into the sewer network from your property.

However, since around the 1950s, combined drainage systems have stopped being used in newly constructed houses, as they struggle to accommodate the amount of foul and surface water that needs to be transported from a modern home into the sewage network.

In addition, a combined drainage system can potentially increase the risk of clean, surface water sewers becoming polluted with foul water.

Is your outside drain blocked?

Should you suspect that you have an issue with your drainage, you need to identify what the trouble is. With a better understanding of the parts that make up your drainage system, you can follow the following steps and hopefully locate and identify the issue at hand, which will then inform your next actions.

Visual inspection

The first thing to do when solving the problem of a blocked drain outside is to carry out a visual inspection of the area you think is blocked and try to understand what is causing the problem.

In many cases the cause of a blockage in the exterior drainage system, particularly around grates, grids, and guttering, is as simple as a build-up of debris, silt and leaves. Alternatively, around sink discharge pipes, the cause could be the dreaded fats, oils and grease (FOG).

However, the cause of the blockage may be deeper inside your drainage system and, as a result, may not be instantly visible.

You can remove and lift manhole covers for a closer inspection of your drains, but how much of the drain you will be able to see will be limited. If lifting manhole covers, it’s important to exercise extreme caution, as they can be very heavy.

We also suggest using the following signs of spotting a blocked drain:

• Smell: the easiest symptom to recognise
• Sink drainage; water takes longer than usual to drain from your sink
• Toilet drainage: water rises or overflows after flushing
• Noises: gurgling sounds from the plughole

How to unblock an outside drain with  DIY solutions

There are a number of solutions that can be employed if you want to try to unblock an outside drain yourself.

Generally speaking, you should check for blockages by assessing the flow of water through the pipes. If you think a foul water pipe is affected, run the water in your sink or flush the toilet to see what happens. If you think a rainwater pipe is blocked, pour some water into the top of the pipe to see how it flows.  

If you want to tackle the blockage yourself, you can use a drain rod or plumber’s auger – also known as a plumber’s snake.

If the cause of the blockage is debris and leaves, simply put some protective gloves on and remove the debris manually.

Contacting drainage experts 

If you cannot identify the cause or location of the blockage, or if you you can but cannot unblock it yourself, you should get the experts involved.

The engineers at Lanes for Drains offer a 24-hour emergency service and can tackle any drainage challenge, using state-of-the-art technology and equipment to locate and remove blockages.

We carry out in-depth inspections of the exterior drainage system using CCTV video footage and 360 ̊ camera technology, to help us understand your drainage problem. From there we will employ electro-mechanical, high-pressure jetting and vacuumation units to clear the blockage.

If your drainage problem is more serious than a simple blockage, for example if you have a  crack in your pipe, we can help too, by using CIPP repair methods or traditional excavation.

Keeping your pipes clear

Prevention is better than the cure when it comes to your drainage system – so don’t wait for your outside pipes to become blocked before thinking about the best way to keep them flowing.

The key thing to remember is to avoid putting anything down the drain that could cause blockages. The Main Offenders to avoid at all costs are:

• Fats, oils and grease (FOG)
• Wet wipes
• Nappies and pads
• Sanitary products
• Tampons, applicators and wrappers
• Condoms
• Razor blades
• Bandages and plasters
• Dental floss
• Medicines and syringes
• Cotton buds
• Hair

Get in Touch

If your drainage problem persists and your drain remains blocked after following these steps, contact the 24 hour Lanes team today for a free consultation on 0800 526 488 or use our online enquiry form.