Does Bleach Unblock Drains?

If you have ever been tempted to reach for the bleach when you encounter a blocked drain, you’re not alone. However, the truth is that bleach isn’t always effective and can have some negative impacts that make the situation worse in certain cases.

Bleach may clear light organic residue or mask unpleasant smells, but it’s not designed to break down the most common causes of drain blockages. That means things like fat, oil, grease, food waste, wipes or structural pipe issues are untouched by bleach. You could also create a health hazard, damage your pipework and kill your septic tank bacteria.

So, can bleach unblock a drain? In most cases, no. For persistent problems, you need a professional drainage inspection – such as a CCTV drain survey from Express Drainage Surveys – which is why we’ve written this guide to help you find the most effective ways of identifying the causes and the role bleach can play.

What causes blocked drains in the UK?

Before we take a closer look at whether bleach is helpful for a blocked drain, it’s important to uncover the cause of your blockage. Here are the most common causes of drainage issues in the UK. Do any of them sound familiar to your blocked drain situation?

Fat, oil and grease: Poured down your sink, these cool and solidify to eventually form a fatberg that bleach simply cannot dissolve.
Wet wipes and sanitary items: Yes, even the flushable options take time to break down, and so can contribute to dense blockages.
Food waste: Whether it’s rice, pasta or coffee grounds, these organic foodstuffs can lodge themselves in your pipes.
Hair and soap scum: A common cause of blockages in bathrooms, these can clog showers and sinks.
Limescale: If you live in a hard water area, mineral deposits can accumulate and reduce the pipe diameter, creating a slower flow over time.
Structural issues: From tree root intrusion and displaced joints to collapsed pipework, a structural issue isn’t something any chemical can solve.

What is bleach, and how does it work?

The standard bleach you can buy in the supermarket is simply a strong chemical cleaner. Most commonly, it will be sodium hypochlorite, widely sold in the UK and a decent disinfectant or whitening agent. But this has led people to assume it’s a heavy-duty cleaning or dissolving agent.

Here’s what bleach can do:

It can kill bacteria and sanitise surfaces
It can break down some lighter organic materials, such as mould or mildew
It can remove an odour by eliminating the bacteria causing it

But here, importantly, is what bleach cannot do:

It cannot dissolve grease or fat
It cannot break down solid obstructions
It cannot remove limescale or mineral deposits
It cannot shift wipes, food or hair masses
It cannot fix structural problems in the pipework

Can bleach unblock drains? The truth

No, bleach cannot unblock a drain. It’s marketed as a cleaner, but it doesn’t make it an unclogger or a fixer. In reality, its usefulness is pretty limited to removing slimy residue, light soap scum and neutralising smells.

In fact, pouring bleach into a severely blocked drain can be quite counterproductive. Instead of making its way through the system, you’ll end up with a pool of hazardous liquid, which creates a health problem and plumbing problem.

The risks of using bleach to unblock drains

Using bleach in drains is not just largely ineffective, but can also present a range of significant hazards, including:

Damage to your pipework, with PVC and metal pipes being softened or weakened when exposed for prolonged periods.
Dangerous chemical reactions, since bleach can react violently with other household cleaners such as acid-based cleaners, ammonia-based cleaners and vinegar.
An environmental impact occurs when bleach enters wastewater systems, contributing to overall toxicity.
Health risks from the strong fumes that irritate your eyes, nose, throat and lungs, as well as the splashback risk in restricted spaces such as bathrooms.
Septic tank problems can be created if your bleach kills the beneficial bacteria needed for the tank to function properly.

At the least, using bleach could end up costing you a lot of money; at its worst, it could impact your health.

What to use instead of bleach

If bleach isn’t safe or effective in unblocking drains, what should you try instead? Here are some better options:

Boiling water: a quick flush for light buildup
Bicarbonate of soda and vinegar: to mask mild odours
Enzymatic drain cleaners: to break down light organic matter gently
Manual tools (such as plungers): to create pressure and dislodge a small blockage
Routine maintenance to flush your system: to prevent gradual buildups that cause blockages

When bleach fails: Signs you need a drainage professional

A blocked drain is a minor inconvenience, but what can you look out for that indicates a deeper issue that requires professional attention? Check out our key warning signs below:

Persistent slow draining throughout the property
Gurgling noises coming from your plugholes
Bad smells that return over and over again
Water backup into your sinks, shower and bath
Outdoor drains that are overflowing
Localised flooding outside or patches of damp ground

Any of the above could point to either a more solid obstruction somewhere in the system or structural damage, such as collapsed or displaced pipework. In these cases, household bleach is not going to help – it’s time to call the local drainage experts.

How Express Drainage Surveys can help diagnose and solve blockages

When you have a blockage and you don’t know the cause, or if you’ve tried the DIY route and it has failed, then a professional CCTV drain survey is the most reliable solution. At Express Drainage Surveys, we offer a variety of services to help you navigate your drainage system, find the cause of your issues and help you set things right again, including:

Get rapid service and precise results without wasting money on ineffective products by contacting our team today – we’re always happy to help homeowners and businesses restore proper flow to their drainage system.

Does Bleach Unblock Drains? The Truth Nobody Is Telling You