I have a rather interesting water hammer puzzle that has not been solvable so far. 1000 "Who's Line is it Anyway" points to anyone who can.

Ok here is the problem:

When my neighbor runs his lawn sprinkler system I am treated to a session of really loud water hammer noises and high pressure spikes. They are so loud that it wakes me up from sleeping.

Also, I can hear his water running in my pipes. In fact, I installed a pressure gauge between my meter and my PRV valve, which the gauge and the PRV are inside my home right where the water line enters through the basement wall. The gauge rapidly oscillates about 2-5psi while his sprinklers are already on and it sounds like I have a faucet on in my home (which I do not). When his valves turn off and on, I get the loud water hammer banging and the keeper needle on my pressure gauge registers spikes up to 180psi.

I am in a residential house on a city water supply. The normal city pressure hovers around 80psi. My meter is about 30 feet from my house near the street. My neighbor's meter is about 4 feet away from my meter on his property. My line is 3/4" copper.

Here are some easy things I have tried so far:

- Checked to see if his line is somehow tied into mine after the meter by checking my meter to see if its spinning while his sprinklers are on. It is not.

- Called the water company to see if they can offer any solutions to the issue. At first they were receptive to help, so they changed both our meters and when that did not work, they informed me they will not do anything else. They actually think Im making this up. This is what they told me after they changed our meters, "If we had pressures at the level you are claiming we would be having problems in the zone."

- Put a water hammer arrester in my home where the water line enters my home. This has not helped and only slightly dampened the noise and reduced the spikes by only about 10psi.

- Shut off the supply line valve between the city main and my meter while his sprinklers are running and this solved the problem but of course is not practical since I cant run out to the street to turn the water off and on every time I want to take shower or run the dishwasher.

- Had a plumber come out, reproduce the problem and then tell me the water company needs to fix this since its coming from street side of my meter. The water company still refuses to help after I told them this.

- Talked to my neighbor about this, he doesn't hear any noises and he feels he doesn't have a problem, so doing any work on his lines is not an option.

I would like to try any more easy things before I move on to harder things like digging up the line near the meter and installing something to eliminate or reduce the noises and spikes. At this point I only have ideas, but I dont know what would work. I have thought about another PRV in line right after the meter, or another water hammer arrester or some combination of both. What would the introduction of a check valve do? Would another hammer arrester even work if its far from the source causing the hammer? Would a larger volume arrester make a difference?

Another idea is to see if our meters share one line from the main. It really seems like our meters are on a tee from a single line to the water main. If this is the case, should'nt our meters each have its own connection to the water main? I dont know how to find out if we are sharing a single line. The line likely runs under a concrete sidewalk and asphalt street. 811 blue stakes can come out and possibly mark the location of the lines, but how do I convince the water company to run separate lines for our meters?

Are there any easy things left to try? What else can I do? Im really lost at what to do next. Thanks for your help!

Here is a pic of the gauge, arrester and PRV coming in my basement--> [s-media-cache-ak0.pinimg.com] The ball valve after the gauge is to shut off the hammer arrester.

- Loosing Sleep in Utah



Edited 4 times.

your pressure reducing valve should NOT allow the downstream pressures to fluctuate like that IF IT IS WORKING properly. After all. that is why you installed it. you and your neighbor may have your meters attached to the same pipe from the city main, since they are so close together and your line is responding to the flow of the other meter.

I would put money on the probability that you and your neighbor share the same tap. Somebody screwed up and buried the mistake.