Which pipe should I use for irrigation?
Which pipe should I use for irrigation?
Low-density polyethylene tubing with barbed fittings for drip lines, and PVC or MDPE for buried mains.
Two things determine whether an irrigation system still works in its third season: filtration and freezing. Emitters have openings measured in fractions of a millimetre and block from silt, algae and the mineral scale that forms as water evaporates at the outlet, so a filter at the tap and periodic flushing of the line ends are not optional extras. Freezing is the other: water left in a line expands and splits fittings, so systems in cold climates are drained or blown out before winter. Backflow protection also matters more than it seems — a hose or drip line lying in a puddle of fertiliser or manure can siphon back into the supply if mains pressure drops, which is why an anti-siphon device or check valve belongs at the connection.
The options, ranked
| Option | Good at | Bad at |
|---|---|---|
| LDPE drip tubing | Flexible enough to follow beds, easy to punch for emitters, and cheap enough to replace. | Degrades in sunlight over a few seasons and is easily cut by a spade or a strimmer. |
| Buried PVC or MDPE mains | Carries pressure to distant zones with no loss and is protected underground. | Needs trenching and must be drained or freeze-tolerant in cold climates. |
| Soaker hose | Simple, no emitters to block, and it wets a whole line evenly in a small bed. | Output varies badly along its length and with pressure, and it clogs from the inside. |
| Pressure-compensating emitters | Deliver the same flow along a long or sloping run, which plain emitters do not. | Costs more per emitter and they still need filtration. |
Technique that changes the outcome
- Fit a filter at the supply and flush the line ends at the start of each season
- Use pressure-compensating emitters on long runs and on slopes
- Bury or mulch over tubing to protect it from UV and from being cut
- Drain or blow the system out before the first frost
- Fit backflow protection at the tap
What goes wrong
- Running unfiltered water through emitters
- Leaving pressurised lines out through a freeze
- Connecting to a potable supply without backflow protection
Compiled practical guidance rather than a published standard. Product formulations vary by brand and market, so read the label — and where the work is structural, electrical or gas, the regulations that apply where you are govern rather than anything here.
Other pipe questions
| For | Use |
|---|---|
| Hot and cold water | Copper or PEX for most installations — PEX is faster and more freeze-tolerant, copper is more robust and takes heat without question. |
| Waste and drainage | Solvent-weld or push-fit PVC-u or polypropylene, at the right diameter and fall — and ABS and PVC cements are not interchangeable. |
| Central heating | Copper, or a barrier-grade plastic pipe — non-barrier plastic lets oxygen into the system and corrodes it from the inside. |
| Boiler condensate | Plastic, never copper, at a generous diameter with continuous fall — and insulate any external run, because frozen condensate is the classic winter breakdown. |
| Gas | Steel, copper of the right grade, or yellow MDPE underground — and in most jurisdictions only a registered installer may do the work. |
| An underground water supply | Blue MDPE for potable water, in one continuous length at the required depth, with no joints under a building. |
| Compressed air | Copper, steel, stainless or a purpose-rated aluminium or HDPE air system — never PVC, which fails explosively. |
Common questions
- Which pipe should I use for irrigation?
- Low-density polyethylene tubing with barbed fittings for drip lines, and PVC or MDPE for buried mains.
- What should I avoid?
- Running unfiltered water through emitters Leaving pressurised lines out through a freeze Connecting to a potable supply without backflow protection
Related pages
- Which pipe should I use for hot and cold water? Copper or PEX for most installations — PEX is faster and more freeze-tolerant, copper is more robust and takes heat without question.
- Which pipe should I use for waste and drainage? Solvent-weld or push-fit PVC-u or polypropylene, at the right diameter and fall — and ABS and PVC cements are not interchangeable.
- Which pipe should I use for central heating? Copper, or a barrier-grade plastic pipe — non-barrier plastic lets oxygen into the system and corrodes it from the inside.
- Which pipe should I use for a boiler condensate drain? Plastic, never copper, at a generous diameter with continuous fall — and insulate any external run, because frozen condensate is the classic winter breakdown.
- Which pipe is used for gas? Steel, copper of the right grade, or yellow MDPE underground — and in most jurisdictions only a registered installer may do the work.
- Which pipe should I use for a buried water supply? Blue MDPE for potable water, in one continuous length at the required depth, with no joints under a building.
- Which pipe should I use for compressed air? Copper, steel, stainless or a purpose-rated aluminium or HDPE air system — never PVC, which fails explosively.
Sources
- Typical range compiled from manufacturer specifications — At One Place