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Fixing a blocked water pipe caused by trapped air

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gices anonymous_2 bernielawrance

It's very frustrating to open your taps and not get any water out of it. Now unless it's the draught season and the water authority board has decided to cut off water supply at specific times during the day, there must definitely be a problem with your water system. In most cases, if water is not coming out of your taps, it's because of an airlock. It happens when an air bubble gets trapped inside your water pipes and then creates a blockage, preventing water from flowing properly in your water system.

solving airlock

You can try some DIY tricks to fix the airlock in your house.

Solution 1

Step 1: Attach a hosepipe to the affected tap (tap where you're not getting any water) and attach the other end to another tap which is working fine (use a tap where there is direct feed from the mains water).
Step 2: Open both taps to allow the pressure from the working tap to force the air back out of the pipes. Leave to run for a few minutes.
Step 3: Turn off the air locked tap first and then the other one.

You may need to repeat this procedure a few times to get rid of the air lock.

Solution 2

If that doesn't solve the problem, then you can try to drain the water system down. You will need to turn off the water feed to your house. Locate the stopcock and turn it off. Then open all taps until all water has been drained down. After that, you need to open each tap only a little bit, let the water flow for a bit, then turn it a little bit more. Keep on opening each tap a little bit more until they are all fully open.

Solution 3

If you're still having problems with the airlock, then you can hire an air compressor to force the air bubble out. After plugging in the air pump, you need to put its hose to the affected tap and let air push the water back to your cold water tank. You will hear bubbles at the water tank to let you know that everything is being pushed back. After 5 minutes, you can disconnect the hose from the air compressor and you should see water flowing back from the tap.

Solution 4

As a last resort and if everything else above does not work, then you will need to call in a plumber. It can cost you on average £90 for a plumber to fix your air lock, so try the above methods before you call one.

gices Published 19 May 2009
I'm a Software Developer and the founder of Clever Dodo. I encourage people to practice MAM (Movement/Arts/Meditation) for a well-balanced and happy life. Born in Mauritius and now living in the UK, I usually blog about fitness, music, spirituality and driving topics to pass on my knowledge.


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MaggieHealy 15 Jan 2010
Hi, I also have a mixer tap in my bathroom can't put a hose from one tap to the other. Have you got any advice on mixer taps? Thanks in advance.
Vaksha 09 Nov 2019

No water upstairs when downstairs is on

We have a CL125 megaflow installed on the ground floor of a 3-storey house. If we use the shower on the third floor, the pressure is very good. However if someone uses the water on the ground or 2nd floor (whether it be flushing the toilets, washing machine, sink etc), the water flow stops on the third floor. Likewise water will reduce or stop on the 2nd and 3rd floor if someone is using water from the ground floor, and similarly, there will be good pressure on the 2nd floor if no one is using any on the ground floor. Our cold water throughout the house is drinking water (which presumably is coming straight from the mains) Is there anyone that can help?

[Migrated from previous topic 12653 dated 17 Apr 2011]

gices 09 Nov 2019

The megaflow is probably losing the air gap so it might need a recharge. You will find instructions on the side telling you how this is done. Usually this should do the trick:

  1. Turn off the water to the megaflow system
  2. Open any hot water tap
  3. Turn the relief valve clockwise to open it
  4. Close the relief valve when the gurgling sound stops

You might need to do that a couple of times a year though.

[Migrated from previous post 2249 dated 23 Aug 2011]

Jackie_2 09 Nov 2019

High water pressure from the mains shared by other houses

techinically who is responsible if the water pressure is too great coming from the mains shared by other houses, my house is the end of terrace we have turned the mains off from outside and did what was suggested but we are getting such pressure the water continues to flow even though the tap is off and i dont mean dripping cos then id know it was the tap someone help , meanwhile i have a airlock in my hot water tap

[Migrated from previous topic 12651 dated 20 Jan 2011]

gices 09 Nov 2019

Does that happen with all the taps in your house. Seems a bit strange that the water keeps flowing if you have turned off the main. If you leave it for 10 mins, do you still get water flowing out even with the mains closed? Just checking to see whether this is not caused by the tap draining the existing water from the pipes.

[Migrated from previous post 2251 dated 23 Aug 2011]

smallbummum 09 Nov 2019

How do I get hot water from my tap again?

My bath mixer tap will only let out hot water if you get it into exactly the right position to the mm, any ideas why its suddenly started doing this?

[Migrated from previous topic 12681 dated 07 Apr 2012]

gices 09 Nov 2019

The rubber tap washer might need replacing. It's usually easy to dismantle a tap to access the washer, so try to see if you can do that and buy another one from B&Q/Homebase and see if that helps.

[Migrated from previous post 2253 dated 13 Apr 2012]

anonymous_2 09 Nov 2019

I have fitted new hot and cold taps in the bathroom (i have 2) and cannot get any water flowing. I had to turn off the supply in the loft by the 2 pipes coming from the main tank marked hot and cold. This was ok until I turned them back on. I cannot get a supply to both bathrooms, the shower or toilet so by replacing 2 taps I have lost supply to most of the house.

[Migrated from previous post 2258 dated 08 Apr 2013]

Keith_Benjamin 09 Nov 2019

airlock in pipes running from a shower pump

I have just fitted a new shower pump (everything was fine until the pump went, no problems to report) more or less the same pump as before. Now I have a continous air lock in the out let supply pipes to the shower/taps in my loft bathroom, so the pump is not detecting demand for water. There is more than enough supply pressure of 1 ltr/min going in. No matter how I configure the outlet pipes to minimise on 90 degree bends, I cant seem to get rid of the airlocks. The pump works fine as you can trick it by placing a magnet in front of the flow sensor switch to make it it think there is a demand for water. Any other tips?

[Migrated from previous topic 12702 dated 05 Aug 2013]

gices 09 Nov 2019

Have you checked there's no loose fittings in the pump? Many times that's where the problem comes from.

Once you've done that, take off the shower head in your loft's bathroom, turn on the cold water and suck on the hose to get rid of any air lock.

See if that works.

[Migrated from previous post 2263 dated 06 Aug 2013]

bobauh 09 Nov 2019

How to clear an airlock in a cold water mains feed

Having drained the hot and cold water system and replaced the taps in the ground floor sink unit, turned on the stop cock, I have hot and cold water from all taps in the 3 storey house EXCEPT no cold water in the ground floor shower mixer valve. Any suggestions to cure this please?

[Migrated from previous topic 12705 dated 29 Dec 2014]

sarssarahsars 09 Nov 2019

Hot water feed to my shower makes a loud whistling noise to it

Hi when the hot water feed is on in shower it makes a whistling noise which we can heat thru the house.Sometimes the hot hot flow completely stops so then only cold water comes thru!!! We just recently changed the shower for a new one thinking it was the old one making this happen. Help!!

[Migrated from previous topic 12706 dated 24 Feb 2015]

bernielawrance 09 Nov 2019

No cold water at all

We have a private water supply, the farmer 'ploughed' our water pipe!! He has replaced the pipe, water now enters the house, both hot & cold tanks have filled. However we are getting no cold water through any taps or cisterns, hot is fine through everything. Could this be an airlock? How can I solve this? we obviously only have a gravity fed system, and before anyone asks... YES I have checked EVERY stopcock/gate valve, I only turned one off, but I have checked them all

[Migrated from previous topic 12707 dated 26 Mar 2015]

bernielawrance 09 Nov 2019

Sorted it (mostly) using a tip from elsewhere on here, blocked the mixer tap, had cold on then opened the hot forcing hot back through the cold pipes, after a minute or so the cold started running.

Just 2 taps and 2 toilets left to fix

[Migrated from previous post 2265 dated 26 Mar 2015]

nyorksannie 09 Nov 2019

overhead shower airblock

There's an intermittent problem with the overhead shower in the main bathroom. Sometimes there is no water until the shower in the ensuite bathroom has run for a few seconds, then it's fine. Sometimes it just works normally, but maybe four or five times a week we have to turn one on before using the other.

[Migrated from previous topic 12708 dated 20 May 2015]

Dodgey-Donna_Wilton 04 Oct 2013

Thank you great help tap now not banging ;-) who needs a man wen you can do it yourself lol thanks again helped a lot cheers xxxx

gerryt 25 Jan 2012
tried the above solution shown in picture at top of page with hose going from tap to tap it fixed it first attempt thank you
Waynester 29 Jul 2011
Solution 1 worked fine for me. It cleared the blockage within two minutes now i have two taps & a toilet working again. Many thanks.
Mark_7 08 May 2011
After trying all sensible solutions with no luck I attached my hoover, turned on, problem solved!!!
Harry_1 21 Apr 2011
We have a mixer tap in both the kitchen and the bathroom, and an air lock in the hot water supply, which tap is it best to turn on? and do you need to leave any other tap running whilst doing this?
Dave_9 14 Feb 2011
Rather than getting NO water I get an 'explosion' of water when I turn the kitchen tap on - happens every day - I assume it has something to do with an 'air' problem??
ChiragPatel 26 Jan 2011
I have a same problem of Air locking in pipeline. I am living at Sea Level but water coming from municipal is on hill. And so all water is going to trap in my pipeline. What will be the best possible way ? Which mecahnism you suggest? IS any instrument in market which extract the air only from pipeline and not water? Please help.. I am tired from air...
Sean_4 31 Dec 2010
Mixer taps are easier to fix and air lock, as mentioned before just cover the tap with your hand (or somthing else) open the hot then the cold with out letting any water come out of the tap. This blows the cold (mains) up through the hot and into the roofspace tank. As for a combi boiler or pressure system it should not have air locks because of the pressure.
CarolLynch 30 Dec 2010
Hi I tried the hoover and it worked first time after days of no water, thanks.
Darren_4 16 Nov 2010
I woudn't recommend a hoover incase water goes into it, however I think it's a great idea and if you use a VAX wet n dry cylinder vaccum i bet it would really do the trick. well i'm going to try it tonight when i get home i'll let you know how it goes.
BO'Grady 12 Nov 2010
The plumber did exactly that and it worked - I was amazed as I'd tried inserting the mains water hose into the bath cold water tap and it failed to shift the airlock despite good water pressure.
AlfredAbela 14 Oct 2010
I got the kitchen tap is dripping water slowly while is open. It got airlock do you think it will come good if we leave it open for a day or two thanks
Paul_14 12 Jul 2010
Just got rid of air lock.had same problem as other people with mixer tap in kitchen; bound up end of tap with gaffer tape turn on hot tap then cold keep firm grip on tap outlet. Worked great. Good luck
Tony_5 01 Jun 2010
I have no hot water cylinder or header tanks as I have a Combi boiler, does this tap to tap meathod still work?
Barry_2 16 May 2010
Put the end part of your hoover to the tap outlet - turn on hoover and this will suck air out thus releasing the blockage - never fails.
EarlyBirdHandyman 06 Apr 2010
You can turn the water off and then remove the pipe fitting from pipe shank under the sink and connect you hose on those pipes. It does the same job as going from tap to tap. A pain to do but should resolve problem (hopefully)
Guhan 04 Apr 2010
I have garden pipe with air blocked I suppose. It happen when the gardener accidently punctured the the pipe when digging the ground. the main pipe was immediately closed and the broken portion was repaired. There is now water coming from all taps inside the house but no water fron the garden pipe. Please advice what to do.
Alec 10 Oct 2009
Hi, The advice already given is great and really helpful but I have a mixer tap in my kitchen and I can't put a hose from one tap to the other. Have you got any advice on mixer taps? Thanks in advance.
Jo_4 06 Oct 2009
Recently we had no water coming out of the tap in our ensuite bathroom. The plumber rang the cold tap on the bath and it started working. But now our shower doesent work. But when you run the hot tap on the bath there is a loud tapping sound in the pipes.