Blog>Expert Advice>What to do if you have a U-bend leak
Last updated: 30 September 2024
What to do if you have a U-bend leak
Have you noticed water leaking underneath your kitchen sink? U-bend leaks often need to be repaired as soon as possible. From DIY repairs to hiring an experienced plumber, we've got everything covered to help you fix the problem.
Why is my kitchen sink U-bend leaking?
A U-bend is a curved pipe used to stop sewer gases and odours from entering your home. This pipe, also known as a P-trap, constantly holds a small amount of water.
If you notice water dripping under your kitchen sink, there's a good chance it is coming from a leaky U-bend.
The most common causes of a leaky U-bend include:
Loose connections - The movement of waste and water can cause pipe joints to become loose over time. Water can leak from the trap If the connections joining it to the sink drain and waste pipe are not tight enough
Poor installation - A U-bend will be more prone to leaks if it has not been properly installed. Poorly sealed and misaligned pipe connections will often result in water leaking underneath the kitchen sink
Worn parts - Rubber washers are often used to create a water tight seal between the U-bend and other pipes in the system. These parts can deteriorate over the years and water can escape through the cracks
Pipe damage - Plastic U-bend pipes are prone to wear and tear. Due to frequent use and changing water temperatures, cracks can form inside the trap pipe. Old fashioned metal U-bends can also corrode and become damaged over time
Blockages - Any debris and food waste that is washed down the kitchen sink can end up in the U-bend. A buildup of waste can cause water to back up, creating high pressure inside the U-bend. This can force water out through the joints and any loose connections
U-bend pipes are also found in your home's bathrooms, connected to the toilet, bath and shower. U-bend leaks are most common in the kitchen due to the many different materials that make their way down the sink on a daily basis.
Food waste, grease, oil and even cleaning chemicals can all cause problems inside your kitchen's plumbing system.
How to fix a leaky U-bend
Fixing a leaking kitchen sink U-bend can be challenging. You will need to know how to safely remove the pipe and how to securely insert any replacement parts. That being said, a DIY fix is possible if you have the necessary skills and equipment.
For the best results, we recommend hiring a professional plumber to do this job for you. An experienced tradesperson can easily locate the source of the leak, complete the repairs and correctly install the new parts.
Search the Checkatrade directory to find reputable plumbers near you.
See the tradespeople we've checked and recommend for your job
Still want to try and fix a leaking U-bend yourself? Read our brief step-by-step guide before you begin:
1. Find the leak
Slowly wipe over the U-bend pipe with a dry paper towel. Next, use a fresh paper towel to wipe over the pipe again. You have found the source of the leak when you see a damp patch appear on the towel.
The most common U-bend leaks are found around the pipe's joints and connections. Try tightening these connections using your hands. We don't recommend using a wrench as over-tightening can cause more damage.
If the U-bend keeps leaking, a loose connection was not the problem.
2. Turn off the water supply
Turn off the water supply before doing anything else. We always recommend switching off the water before doing any DIY plumbing work. There is a risk of accidentally flooding your kitchen if something goes wrong!
3. Remove the U-bend
Carefully unscrew the U-bend from the other pipes in the system. Make sure to place a bucket underneath to catch the small amount of standing water that sits inside the trap.
4. Inspect and replace damaged parts
Closely inspect the rubber washers located around the U-bend connections. Leaks are often caused by worn or misaligned rubber washers. These components will need to be replaced if they are cracked or worn away.
Make sure your replacement washers are the correct size for your sink's U-bend. Parts that are too big will be unable to form a water tight seal.
As well as the smaller parts, closely inspect all other areas of the U-bend. The pipe will need to be replaced if it is cracked, or there are small holes in the plastic or metal surface.
5. Check for blockages
A buildup of debris in the drainage system can cause pressure to build up. When this happens, water can start to leak where the U-bend connects to the waste pipe.
With the U-bend pipe removed, you should be able to see if there is anything blocking the system. If so, clear the buildup of waste away. A professional drainage clearance service may needed to remove a large build up of debris further down in the pipes.
6. Check for leaks
Once you have finished, reinstall the U-bend into the plumbing system. Take care to make sure the washers are aligned and secured in place. Tighten the connections between all of the pipes and turn the water supply back on.
Run the tap and look closely for any dripping water. Wipe down the pipe again with a dry paper towel. If the towel stays dry then you can consider your DIY U-bend repair a success!
When to hire a professional
We recommend hiring an experienced plumber to fix a leaking U-bend.
You may end up causing more harm than good if you try to fix a leak yourself. Even if you know what you're doing, sometimes DIY repairs don't deliver the best long-term results.
A skilled professional can locate the source of the leak and easily install any replacement parts needed. Many experienced handypeople also have the skills needed to fix a leaking pipe.
Hiring a handyperson is a great option if you don't want to pay a high hourly rate for a plumber. Also, a handyperson will likely be able to complete any other small household jobs that you need doing at the same time.
See the tradespeople we've checked and recommend for your job
Cost of U-bend leak repair
Kitchen sink U-bend repair is typically not very expensive. In most cases, this job can be completed in less than an hour and small replacement parts are often available at an affordable price. The average hourly rate for a handyperson in the UK is £30.
If you choose to hire a plumber, you can expect to pay a higher rate per hour. On average, plumbers charge an hourly rate of £50 but this fee varies across the country.
Fixing leaks is bread and butter for plumbers and the price range for this repair work is£77 - £128.
Read our plumber cost guide for a full breakdown of current prices.
Key Takeaways
Common causes of U-bend leaks include worn washers, loose connections and pipe blockages
A leaking U-bend can be repaired by tightening the connections and replacing damaged parts
Plumbers charge an average of £77 - £128to fix a leak
Hiring a reputable plumber
Search the Checkatrade directory to find high quality plumbers in your local area. We only approve tradespeople who pass our checks and work to our high standards. Enter your postcode below to begin browsing plumbers near you.
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FAQs
Should there be water in the U-bend?
U-bends hold a small amount of water at all times. This water sits in the pipe, or P-trap, to prevent sewer gases and bad smells from entering your home.
What is the most common leak under the kitchen sink?
A faulty drain pipe is one of the most common causes of a leak under the kitchen sink. This plastic pipe can become loose and water can leak out where the drain connects to other pipes in the system.
Worn U-bends and damaged overflow pipes can also cause water to drip out. Read our guide to fixing a leak under the kitchen sink to learn more.
Why is my toilet leaking from the U-bend?
A damaged pipe, loose connections and poor installation are the most common causes of a leaking toilet U-bend.
This leak can often be fixed by tightening up the pipe connections or replacing damaged parts. We recommend hiring a plumber to find the source of the leak and fix the problem.
See the tradespeople we've checked and recommend for your job