Ask on any RV forum how to join a water line and you will get three confident answers and an argument. The disagreement is real, and it comes from the fact that these connections behave differently in a vehicle than they do in a house.
Here is what each method actually does, and where each one belongs.
Why RV plumbing is not house plumbing
A house pipe sits still, stays at a stable temperature, and is usually accessible.
An RV water line is vibrated continuously, flexed as the chassis twists, exposed to freezing, and buried behind a panel you can only reach by removing furniture. It also spends months unpressurised and then gets pressurised suddenly when you connect to city water.
Every one of those differences pushes you towards a connection that tolerates movement and does not depend on perfect access.
The four methods
Crimp rings
A copper ring compressed around the pipe over a barbed fitting with a dedicated crimp tool.
Strengths: the strongest and most permanent of the options. Very low profile, so it fits where other fittings will not. Once made correctly it is effectively immune to vibration.
Weaknesses: needs the correct tool for the size, which is not cheap. Needs a go/no-go gauge to verify the crimp. Removing one means cutting it off. Hard to do well in a confined space, and almost every RV joint is in a confined space.
Use it when: the joint is accessible while you are building, and you want it permanent.
Stainless pinch clamps
A stainless ring with a raised ear, closed with pinch pliers.
Strengths: the tool is far cheaper and smaller than a crimp tool, and one tool covers a range of sizes. Stainless does not corrode, which matters in a damp bay. Much easier to fit in an awkward space because the tool only needs access to the ear, not all the way around the ring. Removable with side cutters without damaging the fitting.
Weaknesses: a slightly larger profile than a crimp ring. Quality varies between brands.
Use it when: you are working in a real RV rather than on a bench. This is the method most experienced owners settle on, and the reason is access rather than strength.
Push-fit connectors
The type you push the pipe into and the internal teeth grip it.
Strengths: no tools at all. Fast. Removable and reusable. Excellent for an emergency repair on the road, and genuinely useful for a temporary joint.
Weaknesses: this is where the argument lives. They have an internal O-ring that is a wear item, they are bulky, and they depend on the pipe being cut square and inserted fully. Some owners run them for years without trouble; others report weeping joints after a season of vibration.
Use them when: you need a repair now, or the joint will be inspected regularly. Many owners carry a couple for exactly that reason and replace them with a permanent joint later.
Avoid them when: the joint will be sealed behind a panel where a slow weep can rot a floor before you notice.
Worm-drive hose clamps
A screw-tightened band, the type most people already own.
Strengths: universally available, adjustable, re-tightenable. Correct and standard for larger flexible hose.
Weaknesses: wrong for pressurised small-bore water line, where they concentrate force unevenly and can cut the pipe.
Use them when: the job calls for a hose clamp rather than a pipe fitting, which means sewer hose, larger drain connections, and similar. A stainless worm-drive clamp in 304 stainless is what you want there rather than a plated one that will rust.
Rules that apply whichever you choose
Cut square. A skewed cut is the single most common cause of a joint that weeps. Use a proper pipe cutter, not a knife.
Deburr and check the pipe end. A nicked or oval pipe end will not seal reliably on a push-fit and will not crimp evenly.
Insert fully. Mark the insertion depth on the pipe with a pen before assembly so you can see at a glance whether it has gone home. This one habit prevents most failures.
Support the pipe. Clip the run so the joint is not carrying the weight or the movement of the pipe. A joint that is being levered by an unsupported run will eventually fail regardless of method.
Leave a service loop. A little slack near a fitting means the next repair does not require replacing the whole run.
Pressure test before closing up. Connect city water and leave it pressurised while you check every joint by hand and eye. It is far cheaper than finding out through a soft floor.
Freezing is the other half of the problem
A joint that is perfectly sound will still split if water freezes in it. Fittings are usually more rigid than the pipe, so ice damage tends to appear at connections.
Winterise properly rather than relying on a fitting to survive. A winterising kit with a pressure gauge lets you blow the lines down at a controlled pressure, which is what protects the joints.
What we stock, and what we do not
Being straight about this: we do not currently stock PEX fittings, crimp rings, pinch clamps or push-fit connectors. If you are plumbing a system, you will be sourcing those elsewhere.
What we do have for RV water systems:
- Water hose by the foot for flexible runs.
- Stainless worm-drive clamps for larger hose.
- City water inlet with brass check valve, which is a common failure point and a straightforward replacement.
- HepvO waterless trap, a membrane trap that cannot lose its seal to evaporation or sloshing the way a water trap can.
- Winterising kits.
If there is a fitting range you keep needing and cannot get sensibly, tell us. We would rather stock what customers actually run out of than guess.
Short answer
For a permanent joint you can reach while building, crimp. For almost everything else in a real camper, stainless pinch clamps, because the tool fits where a crimp tool does not. Carry a push-fit or two for emergencies and treat them as temporary unless you can inspect them.
And whichever you use, cut square, insert fully, support the pipe, and pressure test before you close the panel.