A sink that takes longer than usual to empty is often an early sign of a developing blockage. Acting while the water still drains can be easier than waiting until the bowl is full and unusable. The likely cause depends on which sink is affected and what normally goes down it.
What commonly slows a sink?
In a kitchen, fats, cooking oil, grease and food scraps can stick to the inside of the waste pipe and build up over time. Hot water and washing-up liquid do not make grease disappear permanently: it can cool and harden further along the pipe.
Bathroom basins are more often restricted by hair, soap residue, toothpaste and debris around the plug mechanism. A damaged, poorly aligned or inadequately ventilated waste pipe can also drain slowly even when the visible trap is clear.
Start by checking the drain opening
Stop using the sink and let the water level fall. Wearing household gloves, remove any visible hair, food or debris from around the plug and strainer. Clean a removable strainer or pop-up plug in accordance with its instructions, taking care not to lose small seals or fittings.
If standing water will not drain, scoop it into a bucket rather than repeatedly adding more water. Do not pour it into another fitting if several drains are already slow or backing up.
Try a sink plunger carefully
A flat sink plunger can sometimes move a local soft blockage. Cover the overflow opening with a damp cloth, add enough water to cover the plunger cup and make a firm seal over the waste. Use several controlled pushes, then check whether the water drains more freely.
On a double sink, seal the second waste opening before plunging. Stop if a joint beneath the sink moves, leaks or appears loose.
Hot water is not a cure for every blockage
Very hot—but not boiling—water may help with a small amount of soap or soft grease in suitable pipework. Boiling water can damage some plastic pipes, seals and fittings. Never use this approach when the sink contains a chemical cleaner, when the waste pipe is damaged, or when the manufacturer advises against it.
Do not rely on repeated kettles of water to clear cooking fat. Prevention is more effective: allow fat to cool, scrape it into the bin or a food-waste container, collect liquid oil in a sealed container and wipe greasy pans before washing them.
Be cautious beneath the sink
The trap—the curved or bottle-shaped fitting below the sink—can collect debris, but removing it is not always a simple job. Old fittings can crack, seals can be disturbed and water can spill into the cupboard. Tenants should report the fault before dismantling landlord-owned plumbing.
If you are responsible for the property and are confident the trap is designed to be removed, turn off nearby electrical appliances, protect the cupboard, place a bucket underneath and follow the fitting manufacturer's instructions. Stop if the connections are seized, damaged or inaccessible. After reassembly, run a small amount of water and check every joint for leaks.
Signs that the blockage is deeper
- More than one sink, bath, shower or toilet is draining slowly.
- Water rises in another fitting when the sink is used.
- There is gurgling, a persistent sewage smell or wastewater returning through a waste.
- The problem returns soon after a local clean.
- An outside inspection chamber is overflowing.
Stop using affected fittings if wastewater is backing up. A problem outside the property boundary, affecting several homes or involving a public sewer may be the water company's responsibility. A blockage within the home's private pipework will normally need the owner, landlord or their plumber to arrange clearance.
What should tenants and landlords do?
Tenants should report a slow drain early, explain which fittings are affected and avoid dismantling pipework or using strong chemicals without permission. Send a photograph or short video showing how slowly the water clears.
Landlords should treat repeated blockages as a fault to investigate rather than repeatedly clearing the visible trap. The underlying cause could be a poor pipe fall, damaged waste, restricted shared pipe or something entering the system elsewhere. Keep a record of previous visits and what was found.
When should you call a plumber?
- The sink is completely blocked or keeps filling again.
- Plunging and cleaning the visible opening have not helped.
- A trap or joint is leaking, cracked or loose.
- Several fittings are affected or wastewater is backing up.
- The blockage repeatedly returns.
- A chemical drain product has already been used.
For slow or blocked sinks across Essex, call Ricky on 07939 013120 or email Essexemergencyplumbing@gmail.com. Explain which fittings are affected, whether water is backing up and anything already poured into the drain.