Stop Banging Pipes: Fix Water Hammer & Noisy Plumbing
By The FixDelivered Team · Updated 2026-07-05 · 8 min read
That sudden BANG, THUMP, or incessant humming from your pipes can be startling and irritating. Often referred to as 'water hammer', these noises aren't just a nuisance; they can signal potential problems within your plumbing system that, if left unaddressed, could lead to leaks or damage over time. This guide will help you understand why your pipes are noisy and provide practical steps to quieten them down.
What Causes Noisy Pipes?
Several issues can cause your plumbing to make a racket. Identifying the cause is the first step to finding a solution.
1. Water Hammer
This is the most common culprit behind loud banging noises. Water hammer occurs when water flowing through pipes is suddenly forced to stop or change direction, typically due to a fast-closing tap, washing machine, or dishwasher valve. The momentum of the water creates a shockwave, causing the pipes to vibrate and knock against walls or joists.
2. Loose Pipes
Pipes that aren't properly secured can vibrate and knock against their surroundings (walls, floorboards, other pipes) as water flows through them, especially during changes in pressure or temperature.
3. High Water Pressure
Excessive water pressure can exacerbate both water hammer and general pipe vibrations. If your mains water pressure is too high, it puts undue stress on your entire plumbing system, leading to noisier operation and increased wear and tear.
4. Trapped Air
Air pockets within your heating or hot water system can cause gurgling, hissing, or bubbling noises. When these air pockets are pushed through the system, they can also contribute to banging sounds.
5. Faulty Components
Worn-out or faulty components, such as a ballcock in a toilet cistern, a failing pump in a sealed heating system, or a loose washer in a tap, can also generate unusual noises.
DIY Solutions for Noisy Pipes
Before calling in a professional, there are several things you can try yourself.
1. Bleed Air from Your Heating System
If the noise is more of a gurgling or hissing, trapped air is a likely cause, particularly in your central heating radiators.
Tools You'll Need:- Radiator key
- Old cloth or small bowl
- Turn Off Your Boiler: Ensure your central heating system is switched off and has cooled down. This prevents air from being drawn back into the system while you're bleeding.
- Start at the Lowest Point: Begin bleeding radiators on the ground floor, working your way up to the highest radiators in your home.
- Locate the Bleed Valve: This small valve is usually found at the top corner of the radiator.
- Insert Radiator Key: Place the radiator key into the square slot on the valve.
- Open the Valve: Slowly turn the key anti-clockwise. You should hear a hissing sound as air escapes. Hold the cloth or bowl underneath to catch any drips of water.
- Close the Valve: Once water starts to come out in a steady stream (without air), turn the key clockwise to close the valve. Do not overtighten.
- Check Boiler Pressure: After bleeding all radiators, check your boiler's pressure gauge. It may have dropped. Top up the pressure as per your boiler's instructions (typically 1-1.5 bar when cold).
- Radiator water can be dirty and hot. Use a cloth and be careful.
- Do not over-pressurise your boiler. Consult your boiler's manual if unsure.
- If the noise persists after bleeding all radiators.
- If you frequently need to bleed radiators or top up boiler pressure, which could indicate a leak.
- If you are unsure how to top up your boiler's pressure.
2. Secure Loose Pipes
If you can identify specific pipes that are vibrating or knocking, securing them can often resolve the issue.
Tools You'll Need:- Pipe clips (correct size for your pipes)
- Screws
- Drill
- Screwdriver
- Spirit level (optional)
- Torch
- Locate the Source: Listen carefully to pinpoint where the knocking sound is loudest. This might be in a loft, under floorboards, or behind accessible panels.
- Identify Loose Sections: Gently press on pipes near the noise source to see if they move or rattle.
- Install Pipe Clips: For accessible pipes, measure and mark where new clips are needed. Ensure clips are snug but not overtightened, allowing for thermal expansion. Space them appropriately (typically every 1-1.5 metres for horizontal runs, closer for vertical).
- Check for Obstructions: Before drilling, ensure there are no electrical cables or other pipes directly behind your drilling point.
- When working in lofts or under floorboards, be mindful of your footing and potential hazards like wiring or insulation.
- Always use appropriate personal protective equipment (PPE) like gloves and eye protection.
- If pipes are in inaccessible areas (e.g., within solid walls) requiring disruptive work.
- If you're uncomfortable drilling into joists or walls, especially near other services.
3. Reduce High Water Pressure
If your mains water pressure is consistently high (above 4-5 bar), a pressure reducing valve (PRV) might be needed or adjusted.
Tools You'll Need:- Water pressure gauge (can be bought cheaply online or from hardware stores)
- Adjustable spanner (if adjusting an existing PRV)
- Check Your Water Pressure: Attach a pressure gauge to an outside tap or a washing machine connection. Note the reading. If it's consistently above 4 bar, it's considered high for a domestic property.
- Locate Your PRV (if you have one): This is usually found on your incoming mains water supply pipe, often near your stopcock or water meter. It looks like a bell-shaped brass valve.
- Adjust the PRV: If you have an adjustable PRV, there will be a screw or knob on top. Slowly turn it clockwise to increase pressure or anti-clockwise to decrease it. Make small adjustments and recheck the pressure. Aim for 2.5-3 bar.
- Do not reduce pressure too much, as this can affect shower performance and appliance operation.
- If you don't have a PRV, do not attempt to install one yourself unless you are a competent plumber.
- If you don't have a PRV and your pressure is consistently high.
- If you're unsure how to adjust your existing PRV.
- If high pressure is causing frequent issues despite adjustments. A local plumber can assess and install a PRV if needed.
4. Install Water Hammer Arrestors
For persistent water hammer near specific appliances (like washing machines or dishwashers) or fast-closing taps, a water hammer arrestor can be installed.
Tools You'll Need:- Adjustable spanner
- PTFE tape
- Water hammer arrestor(s)
- Turn Off Water Supply: Locate your main stopcock and turn off the water supply to your property.
- Drain the Pipes: Open the lowest tap in your house to drain water from the pipes.
- Install the Arrestor: Water hammer arrestors are typically installed inline with the water supply to the offending appliance or tap. They usually screw directly onto the appliance's inlet valve or can be plumbed into the pipework. Wrap the threads with PTFE tape before tightening with a spanner.
- Restore Water Supply: Slowly open the main stopcock and check for leaks.
- Ensure the main water supply is off before attempting any work.
- Do not overtighten connections, as this can damage threads.
- If you're not confident working with plumbing connections.
- If the water hammer is widespread and you suspect it requires a more comprehensive solution (e.g., multiple arrestors or system rebalancing).
When to Call a Professional Plumber
While many noisy pipe issues can be tackled with DIY methods, some situations warrant professional help. It's always best to call a qualified plumber if:
- The noise persists despite your best efforts.
- Pipes are inaccessible (e.g., behind solid walls or under sealed floors).
- You suspect a more serious underlying issue, like a failing pump or boiler component.
- You are uncomfortable or lack the tools to perform the necessary repairs.
- Any work involves your gas boiler or gas supply – this must ONLY be carried out by a Gas Safe registered engineer.
A professional plumber has the experience and specialist equipment to accurately diagnose the problem and provide a lasting solution. They can also advise on system-wide improvements, such as installing a whole-house water hammer arrestor or optimising your heating system.
What Does a Plumber Charge to Fix Noisy Pipes?
The cost to fix noisy pipes can vary significantly based on the cause and location. As a rough guide for 2026 in the UK:
- Call-out fee: Typically £70-£120, though emergency call-outs can be higher.
- Hourly rate: Around £60-£90 per hour.
- Simple fixes (e.g., securing accessible pipes): £100-£200, including parts and labour.
- Installing a water hammer arrestor: £150-£300 per unit, depending on complexity and location.
- Installing or adjusting a pressure reducing valve: £200-£400, including the valve and labour.
- Tracing and fixing inaccessible pipes: This can vary widely from £300 to £800+ if it requires significant investigative work or remedial building work.
Always get a clear quote upfront to avoid surprises. With FixDelivered, the plumber's callout fee and rates are agreed directly with them before any work begins, giving you transparency.
Get Your Plumbing Sorted with FixDelivered
Don't let noisy pipes disrupt your peace and quiet. If DIY solutions aren't working or you'd prefer a professional assessment, FixDelivered can help you find a trusted expert quickly. We connect you with vetted emergency plumbers near you, ensuring you get quality service when you need it most.
You can tell us your emergency and get a plumber now, or learn more about how FixDelivered works to find a reliable plumber in your area.
Frequently asked questions
What is water hammer?
Water hammer is a common plumbing issue where a loud banging or knocking sound occurs in pipes. It's caused by the sudden stopping or changing direction of water flow, often when a tap is quickly turned off or an appliance valve closes rapidly. The momentum of the water creates a shockwave, causing pipes to vibrate and hit nearby surfaces.
Can noisy pipes cause damage?
Yes, if left unaddressed, persistent noisy pipes, especially severe water hammer, can cause damage over time. The constant vibrations and pressure surges can weaken pipe joints, fittings, and even lead to leaks or burst pipes. It can also loosen pipe supports and damage appliances connected to the system.
How do I know if my water pressure is too high?
You can check your water pressure using a simple pressure gauge, which screws onto an outside tap or washing machine connection. A healthy domestic water pressure typically ranges between 1.5 and 3 bar. If your reading is consistently above 4 bar, your pressure is considered high and may contribute to noisy pipes and other plumbing issues.
Are water hammer arrestors effective?
Yes, water hammer arrestors are very effective at reducing or eliminating water hammer, especially when installed near the source of the problem (e.g., washing machine, dishwasher, or fast-closing tap). They work by absorbing the shockwave created by sudden water flow changes, protecting your pipes and reducing noise.
When should I call a Gas Safe registered engineer for noisy pipes?
You should call a Gas Safe registered engineer if the noisy pipes are directly related to your gas boiler or any gas appliance, or if you suspect any issue with the gas supply pipework. While most noisy pipe issues are water-related, any work involving gas must always be carried out by a qualified and registered professional for safety reasons.
Need a plumber now? Tell us your emergency and FixDelivered will find and confirm an available local plumber near you, usually within the hour.
Written by the FixDelivered Team. Reviewed by Rupert Lowe, Editor. Last updated 2026-07-05.