Leak detection spray vs soapy water on a gas joint

Updated: 22 October 2026

Someone has told you to mix washing-up liquid with water and paint it on the fitting. The bubbles do appear, and that is why the tip survives.

Someone has told you to mix washing-up liquid with water and paint it on the fitting. The bubbles do appear, and that is why the tip survives. Leak detection spray vs soapy water is still an easy choice once you separate today’s bubble from tomorrow’s residue. UK gas guidance wants a proprietary leak detection fluid, wiped off, and it names washing-up liquid as the wrong thing to leave on corrugated stainless steel. The six listings, with GBP prices from the amazon.co.uk capture on 19 October 2026, are on the leak detection spray comparison. Amazon links can earn a commission at no extra cost to you.

Our top picks

Badge	Product	Standard stated	Form	Non-flammable claim	Note	Price	Offer
Best overall	Arctic Hayes Arctic Hayes PH026, 250 ml	BS EN 14291	Brush-on, 250 ml	Yes, on the bullets	8.9	about £4.33	View offer
Alternative	Everbuild Everbuild P18, 400 ml	Not stated	Aerosol, 400 ml	CFC-free only	7.6	about £8.38	View offer
Best value	Arctic Hayes Arctic Hayes PH026M, 120 ml	BS EN 14291	Brush-on, 120 ml	Yes, on the bullets	8.5	about £3.83	View offer

Best overall

Arctic Hayes Arctic Hayes PH026, 250 ml

8.9/10about £4.33

View offer

Alternative

Everbuild Everbuild P18, 400 ml

7.6/10about £8.38

View offer

Best value

Arctic Hayes Arctic Hayes PH026M, 120 ml

8.5/10about £3.83

View offer

On this page

1.Soap will bubble
2.What UK gas guidance says instead
3.Brass, copper, and corrugated stainless
4.When a spray still is not a tightness test

Soap will bubble

Washing-up liquid can blow a bubble on a pressurised joint. Everbuild’s UK reviews say a can is less fuss than mixing a jar. That praise is not a corrosion test. The limit is the residue. Soap is a kitchen detergent, and it dries on the metal. A commercial film is also the wrong residue if you never wipe it off. Guidance names a proprietary fluid and names washing-up liquid as the one to avoid. A quiet joint under soap, or under a dribbling aerosol, is no result. The how to use gas leak detector spray page treats a dead can that way. A bubble, when it grows, means gas is escaping at that wet spot. It does not mean the rest of the installation is sound.

What UK gas guidance says instead

Gas Safe Register’s Technical Bulletin 059 is the UK note to lean on. It describes gas escapes linked to corrugated stainless steel meter connections, including cases where washing-up liquid had been left on the metal. The bulletin points at IGEM/UP/1B and IGEM/UP/1C. Use only proprietary leak detection fluids. Do not use a fluid with more than 30 ppm of halogens on stainless steel. Do not use an ammonia-bearing fluid on copper or brass. Wipe the fluid off when you have finished. Washing-up liquid is named, not hinted at. Proprietary means a fluid sold for leak detection, not a detergent you already own. Installer guidance says use a BS EN 14291 fluid and wipe it off. The gauge test is still the tightness test. EIGA Document 78 also says household soap should not be used on cylinder packages. Buying a named leak detection spray is closer to the bulletin than mixing washing-up liquid. It is not a claim that every shop spray is ammonia-free.

Testsieger

Arctic Hayes Arctic Hayes PH026, 250 ml

8.9/10about £4.33

View offer

Brass, copper, and corrugated stainless

Ammonia-bearing fluid is the problem named for copper and brass. Chlorine and other halogens are the problem named for stainless steel, with the 30 ppm line. Corrugated stainless meter connections are the fitting in the bulletin’s title. You do not need to assay a supermarket bottle. Do not put it on the fitting. A proper fluid still comes off: Liqui Moly says rinse copper and PVC, and Calor says rinse after a cylinder check. The Camping and Caravanning Club’s gas page has told members to use washing-up liquid. The Caravan Club has offered washing-up liquid or a leak spray. Those pages contradict the bulletin. If a club leaflet and Technical Bulletin 059 disagree, follow the bulletin, then wipe the joint.

When a spray still is not a tightness test

A bubble from soap or from a spray means gas is leaving at that wet joint. It is not the first move if the house already smells of gas. Call 0800 111 999, ventilate, and leave switches alone. A Gas Safe registered engineer deals with a meter, boiler, cooker, or fire. On a cylinder you can isolate, shut the valve if bubbles keep forming, ventilate, and do not dismantle the cylinder valve. That sequence is Calor’s. The limit is one visible point, under pressure, for as long as the film stays. Wipe the film off corrugated stainless steel.

Common questions

Will soapy water show a leak?

It can. Washing-up liquid on a pressurised joint will blow bubbles if gas is escaping and the film stays put. Camping advice still relies on that. A bubble is not approval to use the detergent. The damage people are warned about is the residue on brass, copper, and stainless steel after you walk away.

Why do gas engineers refuse it?

Technical Bulletin 059 tells engineers to use only proprietary leak detection fluids and names washing-up liquid on corrugated stainless meter connections. IGEM guidance, as that bulletin states it, bars high-halogen fluids on stainless steel and ammonia-bearing fluids on copper and brass. The fluid is wiped off. A kitchen bottle meets none of those conditions.

Is the problem ammonia, chlorine, or both?

Both, on different metals. Ammonia-bearing fluid is the restriction on copper and brass. Halogens above 30 ppm are the restriction on stainless steel. Washing-up liquid is called out by name in the bulletin, so you do not have to assay the bottle. A shop spray is not automatically free of either. The listing has to say what it is.

Do I still wipe off a proper spray?

Yes. BS EN 14291 fluid is wiped off after a tightness test in the installer guidance. Liqui Moly says rinse copper and PVC. Calor says rinse the fluid off a cylinder check. The commercial product does not earn the right to be left in place. Soap does not either.

Are all shop sprays approved?

No. In this capture only the Arctic Hayes bullets state BS EN 14291:2004. Everbuild, Liqui Moly, and Rothenberger do not. None of the six has been assayed here for ammonia or halogens. A named leak detection spray is the right class of product. The standard line, where you need it, is a further filter.

Does a bubble from soap mean the joint is the only problem?

No. It means gas escaped under that film while the joint was pressurised. Other joints, and the installation as a whole, are untested. If bubbles continue or you can smell gas indoors, shut what you are allowed to shut and call the right help. The spray does not change that limit.

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