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Push-fit vs compression vs soldered joints on UK water pipes
The three common ways to join 15mm and 22mm copper and plastic water pipe in UK homes, when each one makes sense, pipe inserts, which joints come apart again, and why lead-free solder matters on drinking water.
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Most water pipe in UK homes is 15mm (to taps, toilets and appliances) or 22mm (main runs, baths and hot water), in copper or plastic. There are three common ways to join it. Each has its place. Knowing which you are looking at also tells you how to undo it.
Water pipes only. Gas pipework looks similar but is a completely different matter. Any work on gas pipes, gas fittings, boilers or gas appliances must be done by a Gas Safe registered engineer. See when to call a Gas Safe engineer.
Push-fit
The pipe pushes into the fitting and is held by a ring of stainless steel teeth (a grab ring or collet), with a rubber O-ring that makes the seal.
- Pros: no heat, no spanners for most fittings, quick in tight spaces. Most can be demounted (taken apart) and reused, by pushing the collet in and pulling the pipe out, or with a release tool.
- Cons: the fittings are bulkier than solder fittings. The pipe end must be cut square, be free of burrs and scratches, and be pushed fully home. A pipe that is not fully inserted can hold for a while and then let go.
- Plastic pipe needs an insert. A metal or plastic pipe insert goes into the end of plastic pipe to stop it squashing. Use the insert the fitting maker specifies.
- Mark the depth. Measure the insertion depth, mark it on the pipe, and check the mark reaches the fitting.
- Use a proper cutter. A plastic pipe cutter for plastic pipe; a rotary cutter for copper. A hacksaw leaves rough edges that can cut the O-ring.
Push-fit fittings are for the pipe types and uses the maker lists. Check hot, cold and heating ratings on the product page.
Compression
A brass nut and a brass ring (the olive) slide onto the pipe. Tightening the nut squeezes the olive between the nut and the fitting body, gripping the pipe and making the seal.
- Pros: no heat. Works well on copper. Can be taken apart and remade, often with a new olive. Many stopcocks, isolation valves and tap connectors are compression.
- Cons: needs two spanners, one to hold the fitting and one to turn the nut. Over-tightening distorts the olive and causes leaks. Under-tightening weeps.
- Plastic pipe needs a pipe insert in a compression fitting too, and the maker must say it suits that pipe.
- Tape or no tape? The olive makes the seal. See PTFE tape for why tape on an olive is not usually the answer.
A common approach is to tighten by hand, then about a further turn with a spanner, then check and nip up a little more if it weeps. Follow the fitting maker's instructions.
Soldered (capillary)
A copper fitting slides over the pipe ends and is heated with a blowtorch until solder flows into the narrow gap, making a permanent joint. Some fittings have solder already inside (solder ring or "Yorkshire" type); others need solder fed in (end feed).
- Pros: small, neat and permanent. The standard for copper pipe in walls, floors and visible runs.
- Cons: needs a blowtorch, flux and skill. The pipe must be completely drained: water in the pipe stops it reaching temperature. There is a real fire risk near timber joists, insulation and plastics. It cannot be undone without heat.
Lead-free solder on drinking water. In England and Wales, materials in contact with drinking water have to meet the Water Supply (Water Fittings) Regulations 1999. Water Regs UK says that lead solder is illegal on any plumbing system supplying water for drinking, cooking, bathing or washing, and advises asking for lead-free solder when you have plumbing work done. See Water Regs UK on compliant water fittings. Use a solder and flux that say they are for potable water.
Soldering copper water pipe is a skill best learned before you need it, not during a leak. Many householders use push-fit or compression and leave soldering to a plumber.
Which one should I use?
| Situation | Usually sensible |
|---|---|
| Quick repair or new valve on copper under a sink | Compression or push-fit |
| Plastic pipe | Push-fit with inserts, or compression where the maker approves it |
| Somewhere you may need to undo later | Compression or demountable push-fit |
| Inside a wall or under a floor, out of reach | A permanent joint, put in by a plumber |
| Near timber or insulation with no room for a heat mat | Avoid soldering |
| Gas pipework | Not DIY. Gas Safe registered engineer only |
Before you cut any pipe
- Close the stopcock or the nearest isolation valve and drain the pipe.
- Check what the pipe is. In some homes gas and water pipes run close together, and copper gas pipe looks like water pipe. If there is any doubt, stop and ask a plumber or a Gas Safe registered engineer.
- Check for hidden cables before drilling or cutting into walls and floors.
- Have a bucket and towels ready.
The plumbing tool kit lists the cutters and spanners that suit these jobs.
Fittings and cutters at Wickes
Check the pipe size, pipe material and hot, cold and heating ratings before you buy.
We haven't tested this. Figures are as the maker states them (checked 13 November 2026).
JG Speedfit PEM0415W straight connector, 15mm. A push-fit straight connector which Wickes lists for copper and Speedfit PEX or polybutylene pipe (inserts required), for hot and cold water and central heating, with a twist and lock nut and a 50 year warranty (terms apply).
Primaflow brass compression straight coupling, 15mm. A 15mm brass compression coupling with nut and olive at each end, which Wickes recommends for copper pipe and says can be used with PEX if a pipe insert is fitted. The page title says one coupling but a feature line says two are included, so check the quantity.
Rothenberger Pro-Cut copper pipe cutter, 15mm. A compact cutter for 15mm copper pipe, with replaceable blades. Wickes also lists 22mm and 28mm versions.
Are push-fit fittings as good as compression?
Both are widely used on domestic water. Push-fit is quicker and needs no spanners; compression is compact and familiar. What matters most is fitting either one exactly as the maker says.
Can I reuse a compression olive?
It often reseals if the joint is just loosened and retightened. If you take the pipe out, or it weeps, fit a new olive.
Do I need a pipe insert for plastic pipe?
Yes, in almost all push-fit and compression fittings. Use the insert the fitting maker specifies.