Netafim DNL – Dripline Non-Leakage Valve

Netafim DNL – Dripline Non-Leakage Valve

The Netafim DNL (Dripline Non-Leakage) valve is the simple solution to one of the biggest headaches in drip irrigation and hydro systems: drain-back and siphoning. By shutting tight when pump pressure drops, the DNL keeps your lines full of water, prevents airlocks, and stops gravity from pulling nutrients where they don’t belong. This item is also known as a High Pressure Anti-Siphon Valve.

Has a 1/2" male thread; pair it with a reducing socket to fit 3/4" pipe work. 

Why use a Netafim DNL?

• Prevents drain-back: Lines stay primed between cycles, so your drippers start flowing instantly.
• Stops siphoning: Protects against unwanted run-off from downhill or lower-lying drippers when the pump switches off.
• Eliminates airlocks: No more trapped bubbles blocking drippers at startup.
• Even distribution: Ensures all drippers open together once the system reaches the set pressure.
• Proven reliability: Built with Netafim’s trusted quality for years of trouble-free use.

Pressure-Compensated Drippers & Siphoning

Even pressure-compensated (PC) drippers can still siphon if they sit lower than the reservoir or mainline. While their diaphragm shuts flow under low pressure, it isn’t a true check valve—gravity can still pull water through. Installing a DNL at the start of your line stops this problem cold, holding pressure in the pipe and preventing unwanted dripper run-on after irrigation ends.

How it works

The DNL is a compact check valve with a pressure threshold (commonly 0.2, 0.4, 0.6 or 0.8 bar). When line pressure is below the threshold, the valve shuts completely, locking water in place. Once your pump reaches the required pressure, the valve opens and water flows normally through your drippers.

Perfect for

• Hydroponic dripper systems with “up-and-over” pipe runs
• Grow setups with uneven elevation or multiple tiers
• Preventing nutrient waste and unwanted siphoning
• Keeping drippers primed and consistent between irrigation cycles

Pro tip: Combine the Netafim DNL with an automatic air release valve at the highest point of your line for a bulletproof irrigation setup that prevents both drain-back and trapped air.