A clamp saddle (also called a tapping saddle or saddle piece) is a screw-on fitting with which you take a branch directly from an existing line – without cutting the line open. The principle: the saddle is clamped onto the pipe, its seal lies around the tapping point, and only then do you drill through the pipe wall. This creates a tight, pressure-resistant branch for a new irrigation line, a tap or a draw-off point.
Anyone who wants to tap a water line saves, with the clamp saddle, the cutting open, inserting a tee and reconnecting. The method is especially suitable for PE pipes in garden and irrigation construction.
Difficulty: medium · Duration: approx. 10–20 minutes · suitable for: PE pipes in the outdoor and irrigation sector.
What you need
Material:
- Clamp saddle exactly matching the pipe outside diameter (e.g. 25, 32, 40 or 50 mm) – available from the mechanical fittings
- matching outlet at the saddle exit (usually female thread, e.g. 1/2" or 3/4") plus a transition to the desired connection fitting
- reinforcement ring / support sleeve for thin-walled pipes if needed
- sealing tape (PTFE) or hemp for the thread of the outlet
Tools:
- Drill with a metal/wood drill bit or hole saw in the prescribed diameter (observe the saddle manufacturer’s specification)
- Screwdriver or socket wrench to match the saddle screws
- Cleaning cloth, fine abrasive fleece if needed
- Tape measure and pen to mark the drilling point
Preparation & safety
If possible, depressurise the line: shut off the water supply and release the residual pressure at a draw-off point. Pressure-free tapping is much safer and cleaner than tapping under pressure, which requires special tapping fittings.
Choose a straight, undamaged section of pipe with enough space all around. Clean it thoroughly – sand, soil or burr prevent the seal from sealing cleanly. Make sure the saddle diameter exactly matches the pipe: a saddle that is too large or too small does not seal reliably.
If the branch is to carry drinking water, use only components with the corresponding approval (e.g. DVGW) and observe the manufacturer’s assembly specifications.
Step by step
- Choose & clean the spot: mark the drilling position on a straight section of pipe. Clean the pipe and sealing surface so that the saddle seal later sits flush against it.
- Place & screw on the saddle: place the upper part with the seal centred over the mark, fit the counterpart (bracket or lower shell) and screw both sides together evenly crosswise. Tighten the screws firmly but without force – the pipe must not be squeezed. With thin-walled pipes, a reinforcement ring (support sleeve) protects the pipe from being squeezed and ensures a round seat.
- Tap: drill through the outlet of the saddle only through the first (upper) pipe wall. Drill slowly and straight so that the drill does not slip or damage the opposite wall. Use the drilling diameter specified by the manufacturer so that the cross-section matches the outlet.
- Remove chips & connect the outlet: remove loose drilling chips from the saddle exit. Seal the outlet thread with PTFE tape or hemp and screw in the desired connection fitting (transition, tap, compression fitting) hand-tight plus a quarter turn.
- Check tightness: open the water supply slowly and re-pressurise the line. Check the saddle seal and the outlet thread for drips. If necessary, retighten the saddle screws evenly or the outlet slightly.
Common mistakes
- Wrong diameter: a saddle that does not exactly match the pipe outside diameter does not seal – always check the pipe Ø.
- Screws tightened unevenly: the seal then sits crooked. Always tighten crosswise and in stages.
- Over-tightened: with thin-walled pipes, the pipe is squeezed without a reinforcement ring and leaks.
- Drilled through both walls: damages the line and can lead to leaks. Drill through the upper wall only.
- Chips in the pipe: drilling chips not removed clog the filter or nozzles – always remove chips.
- Wrong screws: in the outdoor and underground area, galvanised screws rust – see the note below.
Galvanised vs. stainless steel screws
Many clamp saddles are supplied with galvanised steel screws. These are sufficient for dry, easily accessible indoor installations. Outdoors, in a damp environment or underground, however, you should opt for stainless steel screws (A2/A4): they do not corrode and remain detachable for years – important if the branch ever has to be retightened or dismantled later. A reinforcement ring is generally recommended for thin-walled or soft pipes, in order to distribute the contact pressure of the saddle evenly.
FAQ
Can I tap a water line under pressure?
For tapping under pressure there are special tapping fittings with an integrated shut-off mechanism. In the DIY and irrigation sector, however, it is safer and cleaner to depressurise the line first and then tap it.
Which drill bit do I need for the clamp saddle?
Use the drilling diameter specified by the manufacturer. With PE pipes, a sharp metal or wood drill bit works well; larger cross-sections succeed with a hole saw. A straight, clean cut through the upper pipe wall only is important.
Do I always need a reinforcement ring?
Not necessarily, but with thin-walled or soft pipes it prevents the saddle from squeezing the pipe. When in doubt, rather use a ring – it ensures a round, tight seat.
Does a branch with a clamp saddle stay tight permanently?
Yes, with correct assembly, a matching diameter and evenly tightened screws, the connection is permanently tight. Stainless steel screws and a clean seat of the seal secure the installation long-term.
Further articles & advice
You often continue the finished branch with a compression fitting – how this works is shown in the article Fitting PE pipe compression fittings. For the design of your entire outdoor system, the hub Planning your irrigation helps. Suitable clamp saddles and outlets can be found in our mechanical fittings.
Are you unsure about size, material or pressure rating? The expert advice from KLN supports you in selecting the right clamp saddle for your project.