It raises questions

I spent Monday working on my parents' lawn sprinkler system. I've probably saved them hundreds of dollars over the years. That thing always has problems (which may indicate I'm not very good at fixing it).

This time, there was a broken sprinkler head, weak pressure in one group of sprinklers, a nice little "spring" bubbling up about 6" from another sprinkler head (which accounted for the low pressure), and one sprinkler head that simply refused to work at all, beyond a slow trickle when it was supposed to be spraying.

I got things replaced, dug up, and fixed, until I had only the stubborn trickling head left.

Before digging that one up, I tried backflushing it. It seemed to work for a second or so, then it suddenly shut off again. So I backflushed it a second time. Same result. I got a wire and tried to "snake" out the clog, but it didn't change the situation. It was time to dig.

I dug it up and checked each piece as I took it apart. Everything was in good shape. Then it was time to remove the riser piece that came off the horizontal line. I screwed it out and everything looked good with the horizontal line. Then I flipped over the riser- in the bottom of that pipe, a perfect fit, was a marble. I removed the marble (which was easy to do), reassembled everything, and it worked as it was supposed to.

However, my suspicions have been raised.

My parents had a sprinkler company come work on it a month or so ago when they thought there was a different (major) problem. I think the company fixed the issue without digging or disassembling anything, and they didn't charge much for their work, but... where did the marble come from? 

I helped install this sprinkler system 16 years or so ago. No marbles were used during installation. It hasn't had this issue in all this time. Marbles don't usually pop into existence in sealed systems.

Would an unscrupulous sprinkler repair company place a marble in the line to cause a problem later? One that would be simple to fix, but that they could get a quick service call out of? The marble was small enough to move easily through the horizontal lines, but a perfect fit for shutting off one sprinkler head like a valve. Like it was made or chosen for the purpose. It is slightly smaller than my standard-sized marbles, but only a little. Was it intentional? I don't know, but I have questions.

It's unlikely an elderly couple would have ever discovered the problem themselves- they aren't going to dig it up. If I hadn't done it, what would the company have "found" as the problem when they came back to fix it?

I didn't mention this quasi-suspicion to my parents. I dislike myself for thinking like this, but there are too many questions, and only one obvious answer that comes to mind. 

What do you think? Have you ever heard of this practice or seen a similar experience?

-

Thank you for reading.
Show your support.