Our sprinkler system is nearly 20 years old. When working on the yard lately I noticed the area near these pipes was wet on the ground and then within a couple of weeks it was leaking tremendously like you see in the beginning of the embedded video.
I began by searching for the numbers on the top cap of the part that was leaking. I found out that this is Toro 53300 1″ PVB (pressure vacuum breaker). This is basically a back flow preventer. It keeps the water in the irrigation pipes from flowing back in to the water supply in the event of a loss of pressure from the main.
I ended up finding the part on Amazon. Got it order and delivered. I had a really hard time getting the fittings off. I mean so much that I thought they didn’t come off. I asked on the irrigation subreddit (r/irrigation) and they confirmed that they do indeed come off. They recommend a strange tool but it worked like a charm. They said to use a pair of oil filter pliers. The teeth in the pliers sat perfectly in the grooves on the fittings.
The most important advice I can give you is that when you take the old part off, make sure you pay attention to the orientation of the o-rings and washers. They can be a little tricky if you didn’t watch how it came apart closely. The instructions with this are not very detailed. They really only show flow direction and the assembly of the parts inside the valve.
In conclusion, it’s an easy fix. Dont over pay a sprinkler company for this. You can do it with the right tools and the right parts.