A bathroom sink that drains slowly usually has a partial blockage close to the plughole. Hair, soap residue and toothpaste often build up in the basin waste, the pop-up plug or the trap underneath. Because the water still drains, the problem can grow for weeks before it becomes obvious.
Hair, Soap and Toothpaste Build-Up
Every time you wash, shave or brush your teeth, small amounts of hair, soap and toothpaste go down the basin. On their own they seem harmless, but together they form a sticky, stringy mass.
Hair is often the main culprit. It wraps around parts of the waste and catches soap scum, which slowly narrows the gap water can pass through. Toothpaste can add to this, leaving a paste-like coating inside the pipe.
The Pop-Up Plug and Basin Waste
Many bathroom basins have a pop-up plug that you open and close with a small lever or by pressing it down. Underneath the plug is a short rod and fitting, and these parts are a perfect place for hair to catch and twist.
If the plug does not lift as high as it used to, water may struggle to get past it. Sometimes the plug has slipped out of adjustment rather than being blocked. Lifting the plug out, where your model allows, can show whether there is debris trapped around it.
Bottle Traps and Partial Blockages
Below the basin you will usually find a bottle trap. It is compact and neat, which makes it popular, but its shape means debris can gather at the bottom.
A partial blockage in the trap often causes slow draining rather than a full stop. You may notice the water swirling for a long time, or the basin taking longer to empty after each use. If the trap is clear but the problem continues, the build-up may be further along the waste pipe.
Most basins have a small overflow slot near the top. As well as stopping the basin from flooding, it lets air into the waste, which helps water drain smoothly.
If the overflow becomes blocked with soap or grime, the basin can drain more slowly and may make a gurgling sound. Gently cleaning the slot may help, but it is unlikely to fix a blockage lower down.
When to Call a Plumber
Try to avoid harsh chemical drain cleaners, as they may not clear hair properly and can damage some fittings. If the basin is still slow after you have checked the plug and overflow, or if it keeps coming back, it may be time for professional help.
A plumber can take apart the trap and waste safely and check the pipe beyond it. Our team offers help with slow and blocked sinks in bathrooms and kitchens alike.
If your bathroom basin in Swindon is draining slowly and you would like it sorted, Emergency Plumber Swindon is here to help. Call us on 01793 569521.