Hi Shannon,

It sounds like the valve must have failed. It’s a mechanical piece, and if it ever leaks that means it needs to be replaced.

If you have one like this one ,all you need to do it unscrew it and replace it (wrap teflon tape on the threads before screwing it in). Purchase a new one at any hardware store. It’s called an auto-vent, or in-line vent.

If you have something different please post a picture!

Best,

Laura

That sounds frustrating, especially after you’ve already gone through the effort of levelling the line and clearing everything out. When water starts spurting from a vacuum (anti-siphon) valve under normal flow, it usually points to pressure or airflow imbalance rather than a simple blockage. If the line was recently re-dug, even a slight change in gradient or backpressure from the outlet zone can cause the valve to open more aggressively than it should.

One thing worth checking is whether the valve is rated for the flow your washer is producing, particularly if you’re running newer machines with stronger discharge cycles. Also, double-check that the valve is installed fully upright and above the highest point of the system, as incorrect positioning can trigger spurting. In a similar case discussed by Radley Engineering, issues like this were tied to minor pressure surges and improper vent placement rather than outright valve failure, so it may not be as simple as replacing the part straight away.

If everything looks correctly installed, it could still be wear inside the valve seal after 10 years of use. Swapping it out is a relatively low-cost step, but it’s worth confirming the setup first so the problem doesn’t repeat.