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New Member


Wednesday, September 21st 2011, 10:38am

System keeps leaking and banging

We had a sprinkler system professionally installed about 6 weeks ago by a reputable local company. As each zone starts the system makes a whirring noise as the zone fills that can be heard very loudly in the house. This then settles to a rhythmic chugging as sprinklers do their watering. The noise is loud enough that we cannot run the sprinklers at night as they wake us up so we have to run them in the late evening so they finish before we go to bed.

Here is a good description of the noise from another poster.

Continuous banging noise in house plumbing when sprinkler is running

To me it is very similar to someone starting a lawnmower outside.

The sprinkler folks have thus far been really nice, and they came round and installed a check valve on the house main line to ensure that water was not being sucked from the house when the zones started and making the noise. This made no difference to the noise. They did charge us $200+ for this though.

A few weeks later we were woken in the night to the loud noise the sprinklers make on start up, and it did not stop. I looked out of the window and water was gushing down the street. Eventually I managed to get the water to stop by shutting of the valves on the backflow prevention device. This turned out to be a failed joint between the back flow prevention device and the first master shutoff solenoid. The sprinkler company came out and fixed it the next day and also replaced the check valve with a different type to try and stop the noise. This made no difference and they told me I just had noisy pipes and nothing could be done about it.

Today the sprinkler system is leaking again, this time from a different spot and it is bubbling up through the lawn. I can here the chugging in the house, but not too loudly so the amount of water fortunately seems to be less than last time. This time I cannot turn off the water and I am currently waiting on the city to come and turn it off for me at the meter.
I am yet to get a response from the sprinkler company.

I fear to see our water bill this month.

My questions are this:

1. is something fundamentally wrong with the system? Sound is made by vibration so to me there is obviously something moving that shouldn't be.

2. Is there any chance that the next time one of these pipes break it will be in the house?

3. Since this is the second leak in a month, would you trust the repairs made by the sprinkler company. Should I get another plumber out for a second opinion?

A final important piece of information is that we have very high water pressure. ~120 psi I believe.

Thanks in advance for your comments.


Supreme Member


Wednesday, September 21st 2011, 11:00am

RE: System keeps leaking and banging

...A final important piece of information is that we have very high water pressure. ~120 psi I believe...

Did the irrigation company install a pressure regulator? If you have a static pressure at the meter greater than about 80psi, a regulator is just about required.


New Member


Wednesday, September 21st 2011, 11:34am

They did but it is after the location of the two leaks.

From what I understand the system looks something like:

meter --> split to house (2) --> back flow preventer --> (1) main shutoff solenoid --> regulator --> rest of system

Leaks have occurred at point 1, and I assume point 2. After split to house there is a check valve on the branch that goes to the house.

I do not actually have a plan of the system, so up to the back flow preventer is an assumption because it is buried and wasn't installed by me.


Supreme Member

Posts: 5,382

Location: Metro NYC


Wednesday, September 21st 2011, 1:28pm

The thread you linked is an example of confused terminology - What was called "banging" was actually a noisy water meter. Actual "banging" that is specific to sprinkler systems is a force you can feel through your feet as it resonates through the ground.

With a 120 psi supply pressure, you are getting close to the operating limits of conventional zone valves. It would probably have been best to have installed a separate brass pressure reducer right at the connection point of the system.

Some of this varies according to location (and yours is?) ~ maybe take a few photos of the work (connection point, backflow preventer, master valve, added check valve, water meter)


New Member


Wednesday, September 21st 2011, 2:31pm

Thanks for your response.

The vibration can be felt in the pipes on the back of the toilet in the house where it is loudest. It is this that I am concerned about eventually breaking. This is unlikley the source of the noise as the water in the house pipes cannot be moving as a check valve was installed. It is likely IMO to be coming from the area where the problems have been and reverberating in the house and seeming louder there. There is no noticeable vibration/banging in the lawn when the system is running though, nor is it audible from outside the house.

We are in Texas, which just had its hottest summer :-)

The connection point and check valve are buried and is what seems to be leaking this time. I'll ask them what type of valve and backflow preventer it is and check the max pressure ratings.

Also should a pressure regulator be installed before the connection to the sprinklers and cover both house and sprinkler system or after covering just the sprinkler system?


Supreme Member


Wednesday, September 21st 2011, 5:35pm

With a 120psi static pressure, you better already have a pressure regulator for the house plumbing. Typical household plumbing fixtures are only designed for around 50psi max. Most likely, there is a pressure regulator inside the house just after the water line enters. Usually, a house will have two outside hose bibbs. One bibb will be fed from the water line BEFORE the regulator, and the other will be fed from the water line AFTER the regulator.

If the irrigation regulator is installed after the master valve, then it sounds like it is the PVC kind that are NOT designed for constant pressure. The backflow preventer is most likely brass (so 120psi shouldn't be a problem there). So the only high pressure component question would be the master valve. It likely is NOT brass. Is it designed to handle 120psi?

Properly installed PVC pipe should be able to withstand 120psi. So if you are getting breaks in the system, your installer didn't take his time to do the job right. I'll admit that I only have 80psi at my house, but of the hundred+ PVC joins I put together for my DIY irrigation system, not a single PVC weld joint has failed or leaked.

Do your control valves have flow control on them? If so, can you attempt to adjust the settings and see if that makes a difference?


Supreme Member

Posts: 5,382

Location: Metro NYC


Wednesday, September 21st 2011, 5:36pm

With 120 psi, I expect that you already have a PRV in the house plumbing. Meter noise can resonate through the house, without ever causing physical harm. Can you access the meter when a zone is running, and give it a listen?


Supreme Member

Posts: 482

Location: Houston, Texas


Wednesday, September 21st 2011, 8:39pm

In Texas, it is state law that you be given an irrigation design upon completion of the system installation. You may ask for one.

It is the law and it should not be that hard to get an as built diagram of what happened. You are also supposed to have a material list. I now we haven't had rain, but I hope you got a rain sensor it is required, by state law too.

Check out the TCEQ website and look at the laws covering irrigation. The Backflow should have been inspected upon completion also.

Good Luck :thumbsup: :thumbsup:
:thumbup: :thumbsup:
LI0006121, BPAT0011021, CI0009500


Supreme Member

Posts: 493

Location: Seattle


Thursday, September 22nd 2011, 6:23am

They should have included the PRV with the install at 120 psi..

The next step is to get a PRV in to see if this will reduce the noise.


New Member


Thursday, September 22nd 2011, 9:34am

Thanks for all your responses. Much appreciated.

The leak was eventually stopped by the city in the early afternoon. The guy estimated about 1.5 gallons per minute lost. The sprinkler folks turned up late afternoon and replaced some pvc piping and I think the check valve on the supply side of the backflow preventer with copper or brass. Would have been nice if they had at least come round and stopped the leaking at 7:00 am when they were first notified.

I got no decent explanation as to why this leak happened, so I am still not convinced that we wont get yet another. I'll follow up and see if I get a response.

I'll also go to home depot and pick up one of those pressure testers and check it on the cold water from the washer and see what it is in the house. If it is really high then I assume there is no regulator anywhere and we will need to get one.

Also on the reverberation, are their any simple products that can deaden the noise, such as pipe lagging. We have about 20ft of the main line exposed under the house so this would be easy to add without needing a plumber.

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