A slow-draining sink or gurgling toilet might not seem like a big deal at first. Many people leave it for days or even weeks hoping it’ll sort itself out. But if you’re wondering what blocks drains, the reality is this: most blockages get worse over time, not better.
What starts as a minor inconvenience can quickly turn into overflowing water, foul smells, or even sewage backing up into your home. Understanding what causes blocked drains and acting quickly can save you stress, damage, and costly repairs.
So, What Actually Blocks Drains?
1. Fat, Oil and Grease
Pouring fat or oil down the sink is one of the fastest ways to block a drain.
It goes down as a liquid, but once it cools, it hardens inside your pipes. Over time, this sticky layer thickens and traps food waste, eventually restricting the pipe completely.
Why this is serious:
Grease blockages often form deep in the pipework, meaning DIY solutions rarely reach them. Left untreated, they can cause water to back up into sinks or appliances.
2. Food Waste Build-Up
Even small bits of food can cause big problems.
Coffee grounds, rice, pasta and peelings don’t dissolve properly. Instead, they collect inside pipes especially when combined with grease and soap residue.
Why this is serious:
Food blockages can create strong smells and attract pests. They also tend to come back repeatedly if not cleared properly.
3. Hair and Soap Scum in Bathrooms
Hair is one of the most common answers to what blocks drains in bathrooms.
It tangles together with soap, shampoo and conditioner, forming dense clumps just below the plughole.
Why this is serious:
These blockages slowly restrict water flow until the drain suddenly stops working altogether often when you least expect it.
4. Wet Wipes and Sanitary Items
Despite what packaging says, most “flushable” wipes are not suitable for drainage systems.
Wet wipes, cotton buds and sanitary products don’t break down. They snag in pipes and create stubborn blockages that can affect entire properties.
Why this is serious:
These blockages are a major cause of sewage backups, which can be unpleasant, unhygienic and expensive to clean up.
5. Limescale and Pipe Narrowing
In hard water areas, limescale slowly coats the inside of pipes.
Over time, this reduces the space water has to flow through, making blockages more likely even from normal everyday use.
Why this is serious:
Limescale-related blockages often go unnoticed until drainage suddenly becomes very slow or stops completely.
6. Tree Roots and Outdoor Drain Issues
If you’re dealing with an outside drain, tree roots could be the cause.
Roots search for moisture and can break into underground pipes, allowing soil and debris to enter the system.
Why this is serious:
Root damage can lead to repeated blockages, pipe collapse, and major repair work if not dealt with early.
Why You Shouldn’t Ignore a Blocked Drain
Many people try boiling water or shop-bought drain unblockers. While these might help temporarily, they often don’t remove the blockage fully.
Ignoring the problem can lead to:
Flooding inside your home
Persistent bad smells
Damage to pipes and flooring
Health risks from dirty water
Higher repair costs later on
If you keep asking yourself “what blocks drains and why does this keep happening?”, that’s a clear sign the issue needs professional attention.
When to Call a Drain Unblocker
If water is backing up, draining very slowly, or you’ve had more than one blockage, it’s time to act.
A professional drain unblocker can:
Clear the blockage completely
Identify deeper issues like root ingress or pipe damage
Prevent the problem from coming back
At Plumbing Immediately, we respond quickly and use professional equipment to fix blocked drains properly not just mask the symptoms.
Blocked drains rarely fix themselves. The longer you wait, the worse (and more expensive) the problem can become.
If you’re dealing with a blocked drain, call Plumbing Immediately today and get it sorted before it turns into an emergency.
Blocked Drain? Don’t Wait for It to Get Worse
Slow drainage, bad smells or repeated blockages are signs of a deeper problem. The experienced drain unblockers we connect you with respond fast and clear blockages properly before they turn into flooding or costly damage. Call Plumbing Immediately today and get your drains flowing again quickly and safely.