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What should I do with the old hot water tap when connecting a cold fill washing machine?

As virtually all modern washing machines are cold fill, what do you do with the old hot water tap which is no longer needed?

washing machine blanking cap The old hot water tap should ideally be capped off by screwing a special blanking cap onto it. This is wise because I’ve heard of several cases where the unused hot tap has eventually started to drip, or even where the lever has been accidentally knocked partially on later. This can happen if the hot tap is in the kitchen sink cupboard. I’ve also seen cases where the washing machine itself moved about and knocked the lever when the hot tap was behind the washing machine. This isn’t so likely if your old hot water tap is a proper screw type but the ubiquitous red and blue lever taps are more prone to these issues and it’s safer to blank off any old unused washing machine tap, especially if they are installed out of sight.

Warning about buying blanking caps from DIY stores

I visited several major DIY stores including Wickes and B&Q trying to find a blanking cap for my old hot water tap. They only seemed to stock one blanking cap that looked anything like what I was after but after buying it and opening it, it was just fractionally the wrong size. Presumably it’s designed to cap off some other plumbing requirement. If I remember right I think it was 22 mm – I can’t recall, but I remember taking it over to an actual hot tap at Wickes and through the plastic packaging of both parts it did appear to be the right size. It wasn’t. The size you need if you want to try and source one from a shop is – 3/4″ Brass blanking cap and washer (which is around 19 mm).

washing machine blanking cap Recommended source to buy blanking cap: It took me several wasted visits to large DIY stores, one wasted purchase (of one that was the wrong size) and a lot of time searching the Internet to find this product and I found a good source and linked to it. Sadly it appears they have closed down now, so the best I can recommend is that you search Google for “3/4″ Brass blanking cap and washer” or specifically ask for that at DIY stores or plumbing merchants. The seal is needed for proper sealing off of the old tap but if you don;t get one, try using one from the old hot fill hose.

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  1. avatar Anonymous says:

    do you fit this after the pre-existing tap (ie leave the old blue/red handle control where it is) or do you have to remove the old control piece?

  2. You just unscrew the old hot fill hose from the tap and screw the blanking cap on in its place, and of course leave the hot water tap turned off.

    Make sure the seal is fitted inside the blacking cap and tighten it firmly but there’s no need to use any tools, just nice and firm with the fingers should do. If you want to nip it up with some pipe pliers just nip it a millimetre or so past finger tight.

  3. avatar John Shuttleworth says:

    My hot fill pipe doesn’t have a dedicated tap. Whoever plumbed it in didn’t fit one. The cold and hot fill pipes to the washing machine each share stopcocks with the cold and hot fill pipes to the kitchen sink taps which will obviously have to be switched on again after installing the new, cold-fill only machine. I presume the blanking cap will be sufficient to seal off the hot water pipe at the point where the old hot fill hose currently attaches but would welcome your advice.

  4. Hello John. Yes, the cap has the same thread as the old hot fill hose so when you remove the old fill hose you screw the cap on in its place. However, ideally you’d like the tap to then be turned off so it’s not under any pressure.

    If you can’t turn off this tap because it also supplies the sink tap you will have to rely on the rubber seal inside this cap preventing leakage. It should do, but keep a close eye on it for a few weeks at least.

  5. avatar John Shuttleworth says:

    Just wanted to thank you for your help and advice. I bought the cap from as you recommended. Excellent service – ordered Friday pm, delivered Saturday am. Fitted it Saturday and all seems fine. As you say, I will keep an eye on it for a while. Again, many thanks!

  6. Thank you for a very good and clearly written article, the information about the blanking caps was particularly helpful, and I have used your contact to order the caps I need.

    Thanks again for your information
    Bob Ashton

  7. I also just wanted to say many thanks for this, my blanking cap arrived today from and it fits perfectly (this followed on from 3 fruitless trips to different DIY stores before I read your article).

  8. Many thanks Joanna. I wrote the article specifically to help people like yourself after having a lot of problems trying to buy one myself and it’s great to get feedback that makes it worth while.

  9. Thankyou so much for this advice. I’ve been worrying about the un-used hot water pipe for exactly the reasons you cited as well as a whole load of others including random teenage guests of my daughter fiddling with the lever, boiling hot water spewing everywhere, flooding into the hairdressers shop below etc. I was actually on the verge of ordering a 22mm compression blanking disc from somewhere or other (having spent hours trying to work out what the damned thing is called) so you’ve saved me a great deal of hassle. I shall order the right one now. Really appreciate your advice.

  10. Thanks for the excellent advice. Have ordered a blanking cap today from saving me the hassle of wandering around DIY stores hoping to find the right part.

  11. Thank you Sarah. It’s great to see any of my articles being so useful.

  12. Found this site so useful before so hoping you can advise…
    Just taking out my old machine to make way for new one arriving tomorrow. Old machine has hot and cold – new is cold only. However hot tap when disconnected from old machine and red “valve tap” is turned off still runs. HELP!?! Dont know why as this didnt happen before – any ideas or suggestions welcome before I have to pay a plumber a fee!

  13. avatar Eric Nelson says:

    Looking for the cap in white plastic, are they available?

  14. I wouldn’t think so Eric. I wouldn’t think there was a demand for white plastic ones.

    Sam: Chances are your tap is broken. It’s extremely common with the ubiquitous red and blue tabbed taps most plumbers use. The plastic used for the levers isn’t of good enough quality and they break. This results in you thinking you’ve turned the tap off but the plastic lever hasn’t really turned the metal valve. Either that or it’s turned it almost off but can’t turn it completely off because of another common problem with these taps where they go very stiff.

    The answer is to remove the plastic lever and use pliers to turn the tap off and then use the blanking cap. Otherwise you’d need a plumber to replace the tap.

  15. avatar Eric Nelson says:

    Thanks for thr response much appreciated

  16. I can only endorse the comments above. I ordered from the supplier as suggested, and the part arrived in a couple of days and fitted perfectly. The internet, I’ve found, is a remarkable resource for self-help and self-instruction in so many areas, from advice on addressing nagging worries as in this case, or on sealing a shower tray, to finding recipes for baking terrific cakes and breads, but only because decent people who know what they’re talking about are prepared to share what they know. Many thanks.

  17. Thank you so much for the above information. I was a little dismayed when my new machine arrived this afternoon, only to be told I needed some cap that I had never heard of. It was such a help reading your advice, and even better, I discovered that I live less than 8 miles from their shop – so have just been there in person to pick up the cap.
    Many thanks!

  18. avatar Ross Foley says:

    A friend has moved to a new house. She has an eight year old Indesit washing machine with both hot and cold fill. However, in the house she has moved to, the hot feed has been stop-ended. She is worried that she can’t use the machine with the hot fill hose attached or with an open fill hole if the hose is removed. Do you know if these machines have a non-return valve to prevent water being forced out of the hot fill hole? If not, do you know where we might be able to get a stop for that hole? Thanks in anticipation for any help you can give so that I could set her mind at rest.

  19. Thanks Keith and Hannah.

    Ross: She can use it by connecting the hot and cold hoses to the single cold supply. This might help Is it possible to use a hot & cold fill washing machine with just a cold supply?

  20. Ordered one of the brass blanking caps from on Wednesday afternoon, arrived this morning. Saved lots of time rummaging around the DIY stores trying to find the right one.

    I notice that it has a full rubber insert rather than the usual type washer – assume this is OK?

  21. Thanks Steve, yes I would presume it’s OK too.

  22. Thank you so much-this has helped so much (just got a new washing machine and its single valve…)

    I would be lost if it wasnt for this guide!

  23. I cannot thank you enough for your advice here which I found via Google. I recently got a new washer with just a cold fill behind it instead of the old hot & cold. I recently noticed the floor getting wet around it and found the red plastic lever causing a drip. Getting to a DIY store is difficult at the best of times as I don’t drive so your warning there was timely. I followed your link to – blanking cap (£2.99) came 2 days later and fits brilliantly.

    I’m not exaggerating to say you’re my hero for providing this valuable advice. Thanks to you this non-DIYer woman got this sorted out with little fuss. I have whitegoodshelp on my bookmarks list now!

  24. Thanks very much Gavin and Carol: This is proving to be my most popular bit of advice. I’m really pleased it’s helped so many people.

  25. Thanks for the excellent tip.
    Ordered Friday arrived Monday morning via Royal Mail.

    As a temporary measure you could use the old red or blue, round, plastic connector that came off the old hoses.
    By inserting a 10p piece into it,covering the hole, and then add the washer.
    This is what I did until the correct blanking cap arrived.

  26. avatar jean-louis says:

    You’re a star. That’s exactly the advice i was after, just bought the blanking cap from the link you gave. Brilliant! Thanks

  27. Hi,
    I bought a brass blanking cap this morning from a local hardware store for the very same reason as everyone on this thread. The cap did,nt come supplied with a washer though so was wondering will any type of rubber washer suffice?

  28. I would try the rubber seal from the hot fill hose Derek.

  29. avatar Cliff Stewart says:

    I notice I have a plastic Y-piece attaching the red and blue hoses to my now broken down 10-year old washing machine. The Y-piece is connected to a copper pipe with switch, which switches off the water to both hoses. In anticipation of a new cold-fill machine what do I use to isolate the hot water outlet of the Y-piece when the water is switched on? Would a plastic blanking 3/4″cap be sufficient on the red hose outlet? Are they sold?

  30. Cliff: The set up you describe sounds like you are already running your washing machine (which is presumably a hot and cold fill) as a cold fill washing machine. If your red and blue hoses are attached to a y-piece they must both be being supplied by the same water tap as described here – Washing machine is a hot and cold fill, but I only have a cold water supply

    If this is the case I would just remove the y-piece from the tap as you would no longer need it and just connect the cold water hose for the new washing machine directly to the cold tap.

  31. avatar Cliff Stewart says:

    Thanks for your advice on the y-piece connection. It was just the information I needed.

    Cliff Stewart

  32. This has been a serious time-saver. Just got a new washing machine with a cold only inlet and was quite concerned about leaving the hot pipe with just the lever valve preventing an accidental flood. Like many other posters I had a look in our local big name DIY shops but could only find 15 and 22mm blanking nuts, no 3/4″ ones. Ordered one from the above link on Thursday, turned up on Saturday – Perfect.

  33. This is turning out to be a very useful topic for people and I really appreciate your thanks. It’s very encouraging to see people genuinely being helped, and being very happy about it too.

  34. Excellent article! This was exactly the answer to the problem I had on delivery of my new washing machine today – have sent off for the cap from the link you gave.

    Thanks so much.

  35. Thanks very much for this advice – I visited two DIY stores and was advised that I needed the 22mm blanking nut. They had none in stock so I visited a third and purchased one. As everyone here now knows (thanks to you!), that size is fractionally too big. I ordered one from your link late on Tuesday night, it has just arrived and fits perfectly. Excellent advice, thank you!

  36. Cracking advice. Exactly what I needed. Thanks :-)

  37. I measured the end of my hot water tap and it is 19mm internally but 26mm externally.
    Presumably I need a different blanking cap?
    If so, do you know where I can get one?

  38. Geoff: All washing machine taps are exactly the same. If you connected the washing machine hose to this tap then the blanking cap I described is the one you need.

  39. Excellent advice, thanks. washing machine died yesterday and whilst ordering replacement discovered all new machines to be cold fill only. After investigating reasons for change (google is so wonderfull):decided to cap off old tap as a preventative measure before new one arrives. This information and link is BRILLIANT, lovely to know that it will fit perfectly.

  40. Thanks for the advice. I ordered the blanking plug from the supplier you mention. Having tightened it hand tight and then progressively tighter still, I found that it still leaked ever so slightly. I placed a second rubber seal inside the blanking plug and this did the trick. A very helpful resource, thanks very much.

  41. avatar winslowboy says:

    Fantastic advice – you should get an MBE! I have just fitted a cap to my now redundant hot water valve and, having seen how much water leaks past the closed valve whilst waiting for the blank cap to arrive through the post over New Year, now plan to buy another one and fit it to the cold tap whenever I go away on holiday.

  42. avatar sliding_doors says:

    Like other people your article saved me so much time looking for a solution then visiting DIY shops. Thanks so much

  43. just to echo the thanks for this fantastic help. I had just realised that my new machine is cold fill and I wondered what I would do with the hot fill hose. Thanks to your knowledge and generosity I have been saved hours of boiling my brain thinking and worrying about it.
    thanks ever so much :)

  44. avatar Sue Tortoise says:

    Thanks – exactly the good, clear information I was looking for. Knowing what I needed, I then walked down to a small, local appliance sales, repairs and spares shop and got the part for £1.60.

  45. avatar Plum Bum says:

    You’re dead right. B&Q looked at me like I was a madman when I asked for 19mm – and they actually argued that 19mm caps don’t exist. Yet 22mm is too big, and 15mm is too small.

    Thanks for the link and sharing your expertise. It’s great to find someone who knows what they’re talking about.

  46. Just ordered the blanking cap and a y piece. Moved washing machine that has a hot and cold fill, to fit a new floor but when we reconnected it, the washing was coming out steaming hot! Checked that pipes were connected correctly but am worried about shrinking my clothes! Plan to blank off the hot tap and use the y piece to fill both pipes with cold water. Fingers crossed! Thanks for the advice and web link!

  47. Liz: If your washing was coming out steaming hot the chances are you connected the pipes the wrong way round and the hot water supply was inadvertently connected to the cold valve. This is easily done, sometimes the hoses or taps have been fitted the wrong way round as explained in my article here – Should the washing come out warm or cold?

  48. Thanks very much for the tip on getting hold of the blanking cap it saves me a whole lot of time searching and asking my way round DIY stores, I must add to your words of warning about the red and blue valve levers and I flooded my kitchen when I thought that the cold fill had been shut off but the lever had broken without me realising, you won’t realise how strong mains pressure is until It’s spraying all over your kitchen!!! Thanks again for such quality and easy to understand information.

  49. Thanks graham

  50. Hi,.thanks for the article. We have just bought a new washing machine, that only requires one tap so I want to switch off the hot tap. The problem is that the plastic lever is no longer there, and it looks like the screw of the tap us also missing. is this a job for a plumber is it simple to tighten the tap? after all, I wont be wanting to switch it on again.
    Thanks again, neil

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