Press Fittings or Soldered Copper: How Each Joint Holds

What actually holds a soldered joint and a pressed joint together?

A soldered joint is held by a thin layer of solder that fills the gap between the tube and the fitting. A pressed joint is held by the fitting itself, squeezed onto the tube by a tool, with a rubber sealing ring doing the sealing [2].

In a soldered — or “sweat” — joint, the tube slides into a cup on the fitting with a gap of about 0.004 inch all round. The Copper Development Association’s Copper Tube Handbook explains that solder fills that gap by capillary action, and that the spacing is critical for the solder to flow in and form a strong joint [2]. Flux is what makes it possible: it protects the cleaned copper from re-oxidising while it is heated and lets the molten solder wet the surfaces, and the solder is drawn in whether it flows up, down or sideways [2].

Florida’s plumbing code spells out the sequence: solder joints are made to ASTM B828, cut tube ends are reamed to the full inside diameter, the joint surfaces are cleaned, a flux to ASTM B813 is applied, and on water supply piping the solder and flux must be lead-free — 0.2 percent lead or less [3].

A press fitting has a raised ring near each end — the bead — with a sealing ring of EPDM, a synthetic rubber, sitting inside it [1][2]. The tube is cut square, deburred inside and out, marked at the fitting’s insertion depth and pushed in until it meets the stop; the jaw goes over the bead at right angles to the tube, and the tool runs its full cycle [1][2]. The handbook describes the joint as relying on that sealing ring and the proper use of an approved tool and jaws, and as taking advantage of copper’s malleability and the strength it gains when cold-worked [2].

Nothing is melted. The depth mark still showing beside the fitting afterwards is how you see that the tube stayed fully in [2].

Are press fittings as good as soldered copper joints?

Made to their instructions, both are code-approved, leak-tight joints for a house’s water lines, with pressure ratings well above anything a house should see [2][3]. They are not the same joint, though, and each has its own ways to go wrong.

On paper the soldered joint carries the higher rating. The handbook’s table, taken from the fitting standards, gives a joint made with lead-free Alloy E solder in ⅛- to 1-inch tube a maximum working pressure of 475 psi at 150°F [2]. For general-purpose press-connect joints from ½ to 4 inches it gives a typical range of 0–200 psig and 0–250°F, with a note to confirm the figures for the specific manufacturer’s fittings [2]; one press-system manufacturer lists 300 psi maximum operating pressure and 0–250°F for its copper fittings [1].

The same handbook says the water service pressure in a building should not be higher than about 80 psi [2]. Either joint, made properly, has a wide margin over that.

The real difference is in what each joint asks of the person making it. Soldering takes a flame, a clean and dry joint, and skill — the handbook says plainly that skill and knowledge are required to produce a satisfactory soldered joint [2]. Pressing takes a tool certified by the fitting manufacturer [3] and discipline about preparation and insertion depth [1].

Are press fittings code approved in Florida?

Yes. The Florida Building Code, Plumbing, 8th Edition (2023) — the edition in force as we write this — lists press-connect joints for copper tubing alongside soldered ones [3].

Section 605.13.5 requires press-connect joints to conform to one of the standards in Table 605.5 and to be installed to the manufacturer’s instructions: cut tube ends reamed to the full inside diameter, joint surfaces cleaned, the tube fully inserted, and the joint pressed with a tool certified by the manufacturer [3]. For copper and copper-alloy fittings, Table 605.5 includes ASME B16.51, the American standard for copper press-connect pressure fittings [3]. The manufacturer’s data sheet we cite lists its fittings to ASME B16.51 and to NSF 61 and NSF 372, the drinking-water standards for health effects and lead content [1].

Soldered joints follow in Section 605.13.6 [3]. One requirement covers both: when water piping is finished, it is tested and proved tight under water at no less than the system’s working pressure — or, for piping other than plastic, under an air test of at least 50 psi — held for at least 15 minutes [4].

For underground work, the same manufacturer states that its press fittings are approved above and below ground, and that local inspector approval must be obtained before they are installed below ground [1].

How long do copper press fittings last?

No source we read gives a life in years for a pressed joint in an American house — and none gives one for a soldered joint either. What the sources do give is a track record and a design basis.

The method is not new. The handbook records that press-connect joining was patented in Europe in the late 1950s and is still used successfully there, and that the fittings and tools came to the United States in the late 1990s [2]. The European product standard for copper press fittings, EN 1254-7, says in its scope that the fittings it covers are “designed for a service lifetime up to fifty years” [5].

That is a design basis for fittings made to the European standard, not a promise about any particular house. Fittings sold in the United States are listed to ASME B16.51 [1][3], and the American sources we read do not put a number of years on them.

What shortens either joint’s life is mostly workmanship. For the seal, the manufacturer’s instructions allow no oils or lubricants on it, call for the sealing element that suits the service, and require deburring so the tube end cannot cut it [1]. For solder, the handbook warns that excess flux left behind can corrode the joint — in extreme cases through the wall of the tube or fitting — and that a burr left inside a cut tube can cause erosion-corrosion from local turbulence [2].

What makes a pressed or a soldered joint leak?

A soldered joint usually leaks because the solder never properly filled the gap. A pressed joint usually leaks because the tube was not fully in, the sealing ring was damaged, or the fitting was never pressed. The sources name the causes [1][2]:

• Soldered — oxides and dirt left on the surfaces interfere with capillary flow and can cause failure [2]
• Soldered — an overheated joint burns the flux, and the solder will not enter the joint properly [2]
• Soldered — too much clearance can let the solder crack under stress or vibration [2]
• Pressed — the tube short of its insertion depth, which may result in an improper seal [1]
• Pressed — a burr left on the tube end cuts the sealing ring, or the ring is missing or damaged [1][2]
• Pressed — dents, deep scratches or stamped print lines on the tube where it seals [1][2]
• Pressed — a fitting pushed on but never pressed [1]

How do you know a press fitting was actually pressed?

By the depth mark, by the fitting’s own design on some systems, and by the pressure test that every water line gets anyway.

The depth mark on the tube should still be visible beside the fitting after pressing, which shows the tube stayed fully inserted [1][2]. The manufacturer we cite also designs its fittings so that an unpressed one shows itself under a low-pressure test — 15 to 85 psi with water, or ½ to 45 psi with air and an approved leak-detect solution — and states that this check is not a replacement for the pressure test the code requires [1]. A soldered joint has no such feature; for both, the code’s pressure test is the proof [4].

On our jobs, the depth mark is checked on every pressed joint after the jaw comes off, and the line is pressure-tested before anything is covered, backfilled or closed in.

Do press fittings cost more than sweat copper?

Per fitting, yes: a press fitting is a manufactured part with a sealing ring inside, and a plain solder fitting is not. Per job, it depends on the job — which is why we quote the job rather than the fitting, and why this page has no prices.

What moves the total is everything around the joint. A soldered joint needs the line drained, each joint cleaned, fluxed, heated with a torch, left to cool naturally and wiped of flux [2]. An open flame inside a house also calls for precautions; the handbook points to the ANSI/AWS Z49.1 safety standard [2]. A pressed joint needs a press tool and jaws certified by the fitting manufacturer [3], but no flame and no heat [2].

The Copper Development Association describes press-connect joining as fast and economical [2]. On a particular job, the number of joints, how easy they are to reach and whether the line can be drained decide which way the comparison goes.

Which joint is right for my house?

Either joint meets code [3]. Pressing is the simpler choice wherever a flame is a problem — inside a finished wall or ceiling, close to wood framing, in a home people are living in — and where a line cannot be drained dry, because soldering under wet conditions can be very difficult [2]. A soldered joint made to the standard is still a sound joint, and there is no reason to replace good soldered copper just because press fittings exist.

We install press-fit copper. On a restaurant build-out in West Palm Beach, every joint we assembled was pressed — overhead supply runs, drops into metal-stud walls, ball valves at the branches — and there is no soldered joint of ours in the building. The older soldered copper you can see in our photographs of that job is the existing water service, which was there before us.

Joining onto existing copper is a common job: a valve or a tee is cut into the line and pressed in. The fitting has to land on clean, round tube without dents, deep scratches or other surface imperfections, and the handbook allows a slightly oval tube to be rerounded with a resizing tool [1][2]; we check the pipe’s condition and size first. Where the old pipe is too worn to take a fitting, the question becomes a repipe rather than a joint — and if you are weighing copper against PEX for that, our article on what the research says covers the choice.

What this means in Clearwater, Tampa and across Tampa Bay

In a finished home in Clearwater, Dunedin, Largo or Tampa, a copper repair usually means a joint inside a wall, a ceiling or a vanity, close to framing, insulation and finished surfaces. That is where a joint made without heat or flame [2] is the simpler choice.

The fittings in the photograph above — an elbow, a tee and a coupling, held over a hand-drawn layout of the run — are from a press-fit copper job in Sarasota. Wherever the job is, the line is tested under pressure before a wall, ceiling or trench is closed [4].

FAQ

Sources

We review and cite. We do not reproduce a paper or a manual — follow the links for the originals.

1. [1]Viega ProPress Systems — Submittal Package (SM-PP 0926): system data sheet, product instructions for ½" to 4" fittings, engineering specifications — Viega LLC · rev. 0926Manufacturer's manual · cited as one published example of press-fitting instructions, not as the brand we install; factory-installed EPDM sealing element; 300 psi maximum operating, 0–250°F; listings include NSF 61, NSF 372, ASME B16.51; deburr so the sealing element is not cut, no oils or lubricants, mark the insertion depth, tube to the stop; tube free of surface imperfections including stamped print lines; tube end wiped clean and dry; unpressed connections found at 15–85 psi water or ½–45 psi air, not a replacement for code testing; below ground needs local inspector approval; read 2026-10-11
2. [2]Copper Tube Handbook (CDA Publication A4015-26/24) — Copper Development Association Inc. · 2026Manufacturer's manual · industry handbook; §6–7 solders, fluxes and soldered joints per ASTM B828 (capillary gap about 0.004 in, cleaning, flux, reaming, flux-residue corrosion, about 350–600°F, solder over 0.2% lead banned since 1986, wet conditions); §11 press-connect joints (EPDM seal, approved tool and jaws, depth mark, rerounding, Europe late 1950s, US late 1990s); Tables 14.4a and 14.4b; service pressure not above about 80 psi; read 2026-10-11
3. [3]Florida Building Code, Plumbing, 8th Edition (2023) — §605.5 and Table 605.5, §605.13.5 Press-connect joints, §605.13.6 Solder joints — Florida Building Commission / International Code Council · 2023Law / code · copper fittings in Table 605.5 include ASME B16.51; press-connect: listed standard, manufacturer’s instructions, ream, clean, fully insert, tool certified by the manufacturer; solder: ASTM B828, flux ASTM B813, solder ASTM B32, lead-free (0.2% lead or less), NSF 61; read on ICC Digital Codes 2026-10-11
4. [4]Florida Building Code, Plumbing, 8th Edition (2023) — §312.5 Water supply system test — Florida Building Commission / International Code Council · 2023Law / code · water at not less than the working pressure, or for piping other than plastic an air test of not less than 50 psi, held not less than 15 minutes; read on ICC Digital Codes 2026-10-11
5. [5]EN 1254-7:2021 Copper and copper alloys — Plumbing fittings — Part 7: Press fittings for use with metallic tubes (scope) — European Committee for Standardization (CEN), via the Estonian Centre for Standardisation (EVS) · 2021Government or standards body · scope only, read on the EVS catalogue page 2026-10-11: press fittings with elastomeric seals for copper and stainless steel tubes, designed for a service lifetime up to fifty years; the full standard was not read