My neighbor, an evil witch, says that when my sprinkler system runs it is causing her pipes to shake (her words, water hammer I suppose). This isn't a new issue, apparently it has happened for years including with the previous owner, I just recently had my sprinkler system repaired so it's the first time it has been a recurring problem for me. I don't hear anything in my house while the system is running.

When we repaired the sprinkler system we checked and my meter runs when a zone is on but her meter is static, so I know my sprinklers aren't somehow connected to her system.

Our shut off valves are in the same meter box next to the street. I'm not sure if this means we share a Y off the main from the street or if they're separate.

My googling wasn't overly helpful, but two suggestions were that if we share a Y off the water main it is undersized and my sprinkler system is pulling too much pressure? I'm definitely not a plumber but that doesn't make much sense to me. If that was the case our entire neighborhood would have this issue. The other suggestion was a faulty pressure relief valve somewhere that bounces due to the increase in pressure, but I'm not sure if that would be on my side or hers, and I have no idea where that would even be.

Are there any other suggestions to check what the issue may be?

Just seems mighty implausible. If she's that much of a See You Next Tuesday, is the $100 solution even going to satisfy her? It makes perfect sense for the rational neighbor, but.....

If she's the evil witch of the west refer her to the wizard of oz.

BenTheGoodAg said:

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I'd be tempted to just give her the utility's number and let her call them to deal with it.

But seriously, if she's having supply issues, it's really up to the utility to solve them. I'm not familiar with the range of supply configurations, but I think it's typical to have a pressure regulator to reduce the pressure from the main to your house. Maybe there's an issue with hers/yalls?

ETA - It also sounds like she may be needing some water hammer arrestors installed. Water hammer is present when you're changing valves and not running in steady state, so something doesn't make sense there either. Ultimately, I don't really think that's your issue. Don't think I've ever heard of an arrestor for sprinkler systems.

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Yeah its strange because she says the banging is constant while the sprinklers run, not just when it turns on or switches zones.

I do believe her though. No joke, when I turned the valve on the backflow the first time she was outside within 30 seconds. So she's hearing something I just don't know what or why

There was a utility truck parked in front of her house earlier but I didn't get a chance to talk to the guy before I had to leave. I'll turn my sprinklers on tomorrow to draw her out and see what she says

I wouldn't touch that tar baby.

Wow ... well, this is cheaper than a plumber or home inspector visit but I think this saga will stump these guru chumps
https://www.moneypit.com/

I don't believe your system can cause hammer unless crossed.

I experience symptoms like these, but it's in my own house while my sprinklers are running.

It's not only a water hammer sound when the system starts or changes zones, but a constant rattling/tapping sound from near where the water enters the house while the system is running.

Might this indicate that the pipes from the main to the house and the sprinkler system are not balanced in size?

If it matters, my interior pipes were galvanized until pretty recently. Now all PEX, but the sound continues (maybe slightly quieter with PEX).

Apache said:

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Could be the copper supply lines from the meter to your respective houses are so close they touch (assuming you share a meter box) and the vibrations when your system runs carry down her supply line to her house.

I've installed sprinklers for 25 years and this is the only thing I can figure. Good luck.

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If this was the case would I hear it in my house too?

Vibrations might not reach your house due to copper yard line being severed at irrigation system tee.
Just spitballin' here…

Right, it could be any of those things. Also, it could be just as likely that it's poorly installed on her end, too. Pipes that are lacking enough supports, lack of arrestors, improper transition between materials, etc.

OP, at the end of the day, as long as your plumbing is installed on your property, and coming from your meter (check), you're under no obligation to modify your plumbing to fix her issue, and given the unknowns on her system and her attitude, I wouldn't offer it.

Even if it's because two pipes are touching in the box (which I doubt), that doesn't mean it's on you to fix.

tgivaughn said:

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Wow ... well, this is cheaper than a plumber or home inspector visit but I think this saga will stump these guru chumps
https://www.moneypit.com/

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You got a twofer out of Money Pit this week

Where did I say it was his responsibility to fix?
All I did was speculate on why his sprinkler is causing the neighbors pipes to rattle.

Does your neighbor have a pressure reducing valve on their line after the meter ? When these start failing they can cause all sorts of water hammer issues.

ABATTBQ11 said:

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Turn her supply off and run the sprinklers, but don't tell her. She shouldn't hear anything, and you want this test to be blinded. If she says she does, a) it's likely because she sees the sprinklers running and b) ask to go in and hear for yourself. If there IS some kind of sound, check her water to see if it's running. If it is, you've both got issues.

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Good test case. Just run one of the legs on the other side of her house so she might not see it.

karmapoliceman said:

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I experience symptoms like these, but it's in my own house while my sprinklers are running.

It's not only a water hammer sound when the system starts or changes zones, but a constant rattling/tapping sound from near where the water enters the house while the system is running.

Might this indicate that the pipes from the main to the house and the sprinkler system are not balanced in size?

If it matters, my interior pipes were galvanized until pretty recently. Now all PEX, but the sound continues (maybe slightly quieter with PEX).

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Mine does the same thing. I have no clue what's causing it. All my inside lines are copper FWIW.

Reviving this for my current problem. I saw a leak this weekend at a sprinkler head and replaced it, but it's still leaking so I'm going to replace the solenoid valve. It's leaking out of the top of the sprayer head and I didn't really notice that in the old one until I replaced it. This sprinkler head is probably the lowest in elevation of that leg.

Pretty sure I had to replace one on this system 10-12 years ago and the system is about 30 years old.

OP, your neighbor isn't crazy but could be overly sensitive.

I also can hear a hammering/thumping when my neighbors sprinkler is running. The water main our houses runs up the property line and my master bedroom is on this outside wall. Mine is not loud and is a very subtle noise but does sometimes wake me up in the morning. I hear noises like this much better than my wife who wouldn't even hear it if I pointed it out to her. I've confirmed it by the noise stopping the moment their zone shuts off. I can also hear it cycle through the zones.

That said, In the 23 years I've lived here it hasn't bothered me enough to do anything about it and I doubt I ever will....

Whoop Delecto said:

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You want to replace the diaphragm assembly inside the valve body. I generally buy a complete new valve and swap out the guts from the new one into the leaking one.

https://www.linquip.com/blog/parts-of-sprinkler-valve/

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OK, will pull off the top and see what it looks like inside. Good advice.

I took apart one valve and inspected the diaphragm and spring in it looked in real good condition. I have to check the other valve in the area because I'm not sure which one controls that specific sprinkler head that was leaking. I know the second valve is the solenoid I replaced before because I can see my splice job on the wiring. Problem is that I will have to dig up the valve box to be able to get channel locks on the valve head.

I would ask if I could come to take a listen while my sprinklers were running. If she's hesitant then she may be overblowing it and you can respond accordingly. Otherwise, if it's an issue come up with a neighborly way forward. Never heard of that happening but nothing surprises me these days.