Water pressure spikes after using shower or washing machine.
#1
04-20-22, 12:02 AM
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Water pressure spikes after using shower or washing machine.
Already replaced water pressure regulator, is it defective? Do I need an arrestor as well, where should I install? It was set to ~40psi, spikes as high as ~100psi!
#2
04-20-22, 11:07 AM
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Start by telling us more about your water system. I assume you are on municipal water.
Where are you measuring your water pressure?
When specifically are you measuring the pressure and seeing these spikes?
Where are you measuring your water pressure?
When specifically are you measuring the pressure and seeing these spikes?
#3
04-20-22, 11:14 AM
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Hi,
Yes I'm connected to municipal water, I've been told mainline is 100-150psi since we're up on a hill.
Measuring water pressure at the cold line hookup of my washing machine.
Seeing the spike almost immediately after shutting water off at shower, see a similar spike after washing machine fills up and pressure is measured at hot water heater tank.
I looked in to water hammer arrestors, I suspect this may be due to inertia, but was also told by a plumber this could be due to a faulty water pressure regulator. That was recently replaced and issue continues.
Yes I'm connected to municipal water, I've been told mainline is 100-150psi since we're up on a hill.
Measuring water pressure at the cold line hookup of my washing machine.
Seeing the spike almost immediately after shutting water off at shower, see a similar spike after washing machine fills up and pressure is measured at hot water heater tank.
I looked in to water hammer arrestors, I suspect this may be due to inertia, but was also told by a plumber this could be due to a faulty water pressure regulator. That was recently replaced and issue continues.
#4
04-20-22, 11:46 AM
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I've been told mainline is 100-150psi since we're up on a hill.
You said the PRV was replaced and the problem remains.
What is the problem.... measured spikes or pipes banging ?
Some hammer arresters will stop the banging.
#5
04-20-22, 12:34 PM
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Sn3akyP3t3
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#6
04-20-22, 01:24 PM
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The spikes in water pressure are what concern me the most, especially since we live on the 2nd floor. My undersink water filter said not to exceed 40psi, almost sounds like water is spraying in the freezer when the ice machine fills and the pressure is high. No pipes banging but the surge in water is somewhat audible.
I don't believe there's an expansion tank, haven't seen anything like that anywhere.
I don't believe there's an expansion tank, haven't seen anything like that anywhere.
#7
04-20-22, 02:17 PM
Member
The spikes after using hot water are caused by the water heater going through a cycle. You have a check valve, probably at your water meter, therefore you have a closed system and that is why the pressure spikes so high after a water heating cycle. You need a thermal expansion tank, this is exactly what they are for and why they are required.
I am guessing this is a recent problem you have. All water utilities periodically change water meters on a regular basis. Most likely yours was recently changed. Almost all new water meters have check valves in them to prevent water from your system from backfeeding into the utility system. It's a pollution prevention device.
I am guessing this is a recent problem you have. All water utilities periodically change water meters on a regular basis. Most likely yours was recently changed. Almost all new water meters have check valves in them to prevent water from your system from backfeeding into the utility system. It's a pollution prevention device.
Sn3akyP3t3
voted this post useful.
#8
04-24-22, 03:48 PM
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I would suggest installing an expansion tank as well. If its not the current problem causing your present issue it could lead to problems later. If the previous PRV was faulty and allowed backflow then with the new hardware you now have a potential closed system pressure surge problem waiting to happen.
#9
04-25-22, 05:23 AM
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Has your pressure reducing valve been adjusted to the correct pressure? Some are fixed pressure but some are adjustable.
#10
04-25-22, 03:18 PM
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Thanks everyone! From my understanding, an expansion tank is like a much larger water pressure arrestor correct? The building was constructed in the early 1990's in California, when did it become a requirement to have the tank? I'm wondering if it used to have one and at some point was removed...
I watched a video on how to install, it looks like I need to implement a copper T-fitting to accommodate it, is this something that is sold individually or would I have to solder the pieces together? Couldn't really find one, maybe I was searching wrong.
Would a large water arrestor be sufficient?
Also sent a message to my local water district asking if they had possibly changed anything in my neighborhood that could have affected my water pressure.
I watched a video on how to install, it looks like I need to implement a copper T-fitting to accommodate it, is this something that is sold individually or would I have to solder the pieces together? Couldn't really find one, maybe I was searching wrong.
Would a large water arrestor be sufficient?
Also sent a message to my local water district asking if they had possibly changed anything in my neighborhood that could have affected my water pressure.
#11
04-26-22, 05:12 AM
Group Moderator
A pressure tank does nothing to limit or control your water pressure. It is a storage tank used in well systems so the pump doesn't have to turn on and off every time you use a little water.
#12
04-26-22, 10:39 AM
I'm concerned that we're sending the OP the wrong direction.
If I read the thread correctly, the water pressure spike happens immediately after the hot water is shut off.
If it was 10 minutes later, I'd agree that a pressure tank is required as the cold water heats back up, it expands and increases system pressure. But assuming it's happening immediately after, that's probably not the cause.
When you say the pressure spikes, is it just for a moment? Or does the pressure go from 40psi before taking a shower, to 100psi, then just stays at 100psi until the next time you open a faucet?
Can you clarify:
* Pressure when the system isn't used fo a while:
* Pressure while the shower or washer is running
* Pressure immediately after turning off the shower/washer
* Pressure 15-20 minutes after turning off the shower/washer
If I read the thread correctly, the water pressure spike happens immediately after the hot water is shut off.
If it was 10 minutes later, I'd agree that a pressure tank is required as the cold water heats back up, it expands and increases system pressure. But assuming it's happening immediately after, that's probably not the cause.
When you say the pressure spikes, is it just for a moment? Or does the pressure go from 40psi before taking a shower, to 100psi, then just stays at 100psi until the next time you open a faucet?
Can you clarify:
* Pressure when the system isn't used fo a while:
* Pressure while the shower or washer is running
* Pressure immediately after turning off the shower/washer
* Pressure 15-20 minutes after turning off the shower/washer
#13
04-26-22, 10:52 AM
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Hi Zorfdt,
The pressure remains spiked until relieved by opening a faucet, flushing toilet, etc...
Pressure set at PRV - ~40psi
Pressure while water is running - ~40psi
Pressure immediately after shutting off shower/washer - varies from ~40psi, to 100psi. I have not confirmed if this only happens with hot water. It does seem to need the water to run for a couple minutes before it happens, for example I don't think it spikes if I just run the water for 10 or 15sec.
Pressure after 15min - varies as mentioned above, does not seem to relieve itself overtime.
Water district responded to me and said they have not made any changes in my neighborhood.
The pressure remains spiked until relieved by opening a faucet, flushing toilet, etc...
Pressure set at PRV - ~40psi
Pressure while water is running - ~40psi
Pressure immediately after shutting off shower/washer - varies from ~40psi, to 100psi. I have not confirmed if this only happens with hot water. It does seem to need the water to run for a couple minutes before it happens, for example I don't think it spikes if I just run the water for 10 or 15sec.
Pressure after 15min - varies as mentioned above, does not seem to relieve itself overtime.
Water district responded to me and said they have not made any changes in my neighborhood.
#14
04-26-22, 11:42 AM
Group Moderator
I would replace the pressure reducing valve (PRV). Yours might be leaking and slowly letting higher pressure water get by. During use this slight leakage isn't noticed but you may notice the water pressure inside the house slowly rise until it matches the supply from the city.
Zorfdt
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