Fix a Leaking Anti Vacuum Valve on Your Espresso Machine
By Bella Barista | Published: 2026-10-23
Category: Tips & Care
Learn how to diagnose and fix a leaking anti vacuum valve on your espresso machine. Step-by-step guide for replacing the Lelit Anti Vacuum Valve.
Quick answer
A leaking anti vacuum valve usually means the internal seal has failed. Replacing it with a compatible part like the Lelit Anti Vacuum Valve ($9.74) is the most reliable fix.
Why it leaks
The anti vacuum valve sits on the steam boiler and opens to release pressure when the machine cools. Over time, mineral deposits or a worn rubber seat prevent it from sealing completely, causing water to drip or steam to escape during operation. This is a common wear item on machines with a steam boiler, not a sign of a major problem.
Replacement vs. cleaning
Some leaks can be fixed by cleaning the valve seat with a descaling solution, but if the rubber seat is cracked or deformed, cleaning won't help. Replacement is the surest path. The Lelit Anti Vacuum Valve is a direct drop-in replacement for many Lelit and compatible machines, and at $9.74 it's an inexpensive insurance against water damage.
Diagnosis and repair steps
- Symptom: Water drips from the valve outlet or steam escapes when the machine is heating or idle. You may also hear a hissing sound.
- Likely cause: Worn or mineral-encrusted rubber seal inside the valve. The valve cannot close fully.
- Corrective action: 1. Power off and unplug the machine. Let it cool completely. 2. Remove the valve (usually unscrews from the boiler). 3. Install the new Lelit Anti Vacuum Valve with a little plumber's tape on the threads. 4. Tighten gently—do not overtighten. 5. Power on and test for leaks. If the leak stops, you're done. If it continues, the boiler fitting or gasket may be damaged.
- Stop or choose another option: If you are not comfortable working around a hot boiler or removing fittings, or if the leak persists after valve replacement, contact a professional technician. Do not operate a leaking machine—it can cause electrical shorts or scale buildup. Safety first: never work on a hot or pressurized machine.
Product facts
- Lelit Anti Vacuum Valve: Lelit Anti Vacuum Valve At $9.74 (catalog price $14.99), this valve is a cost-effective, factory-matched replacement that restores proper sealing without guesswork.
Lelit Anti Vacuum Valve
