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Old 06-13-2016, 10:34 PM   #1
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Decreasing water pressure


When we moved into our house 10 years ago, we had great water pressure. We could shower and flush a toilet at the same time with no problem. In the last year or so, the pressure has slowly dropped. Now if we're in the shower and the toilet is flushed, the pressure in the shower becomes just more than a trickle. I'm using these as an example but it applies to the rest of the faucets, the washing machine, etc. Only one can really be used at a time.

We live in the country, so we have a well. It comes in the house and goes to the tank that is in the photos. The house is heated by baseboard heat. (I don't think that matters but mention it since it uses hot water)

I haven't seen any evidence of a leak anywhere.

What do I have to do to get our water pressure back?
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Old 06-14-2016, 09:39 AM   #2
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Re: Decreasing water pressure


Does the pump run more often?
It sounds like a water logged pressure tank. It happens after a time with the type of tank you have. The fix is simple. Pump some air into the tank.
Somewhere on the tank is a schaeder valve. It looks like the stem on tire where you fill it. Turn off the pump and pump some air into the tank.

It could also be a filter issue. If you have filters or a water softener they could be clogged. Remove the filters or bypass the softener and see if the pressure improves.
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Old 06-14-2016, 12:47 PM   #3
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Re: Decreasing water pressure


From your description, you have a flow problem (not enough flow), and you may have a pressure problem. The two are different, but sometimes related. A low flow problem can be caused by a blockage in the pipes, sometimes due to pipe corrosion. A low pressure problem can be caused by a defective pump, a defective pressure switch, or pipe blockage causing pressure loss.

To solve the problem, you need to identify the cause. Pressure drop is easy to identify, you purchase an inexpensive pressure gage at any big box store, and measure the pressure at faucets in your house. Most well pumps are set to turn on at about 30 - 40 psi, and turn off around 60 psi. So your pressure at the faucet should be between the on pressure and the off pressure. If it is low, you have a pressure issue. If the pressure is correct, but the flow is low, you have a blockage issue.

If the pressure is low, you start by looking at the gage which should be on the well T that leads into the pressure tank. You should be able to watch the gage as the pump turns on and off. If the pressure never reaches the correct off pressure, and the pump keeps running, you have a bad pump. If the pump turn off before you reach the design off pressure, you may have a bad pump switch, or the switch needs adjusting. Often the switch goes bad due to corrosion, in which case you need to replace the switch.

If the pump cycles too quickly, you may have a pressure tank that is out of air. You may be able to pump it up, but it may have a burst bladder, in which case you need to replace it.

This is not the entire picture of what can go wrong, but it should be a start. I would get the pressure gage, make some readings, then you can at least narrow down the issue.
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Old 06-14-2016, 03:51 PM   #4
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Re: Decreasing water pressure


Quote:
Originally Posted by Daniel Holzman View Post
From your description, you have a flow problem (not enough flow), and you may have a pressure problem. The two are different, but sometimes related. A low flow problem can be caused by a blockage in the pipes, sometimes due to pipe corrosion. A low pressure problem can be caused by a defective pump, a defective pressure switch, or pipe blockage causing pressure loss.

To solve the problem, you need to identify the cause. Pressure drop is easy to identify, you purchase an inexpensive pressure gage at any big box store, and measure the pressure at faucets in your house. Most well pumps are set to turn on at about 30 - 40 psi, and turn off around 60 psi. So your pressure at the faucet should be between the on pressure and the off pressure. If it is low, you have a pressure issue. If the pressure is correct, but the flow is low, you have a blockage issue.

If the pressure is low, you start by looking at the gage which should be on the well T that leads into the pressure tank. You should be able to watch the gage as the pump turns on and off. If the pressure never reaches the correct off pressure, and the pump keeps running, you have a bad pump. If the pump turn off before you reach the design off pressure, you may have a bad pump switch, or the switch needs adjusting. Often the switch goes bad due to corrosion, in which case you need to replace the switch.

If the pump cycles too quickly, you may have a pressure tank that is out of air. You may be able to pump it up, but it may have a burst bladder, in which case you need to replace it.

This is not the entire picture of what can go wrong, but it should be a start. I would get the pressure gage, make some readings, then you can at least narrow down the issue.
Good job Dan. Well explained.
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Old 06-14-2016, 06:37 PM   #5
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Re: Decreasing water pressure


Thanks for the explanations!

How would I know how often the pump runs?

The house was built in 1999, would a 17 year old house have blocked pipes after that long?

Where is the pressure switch?

How do I know what the correct off pressure is? My tank says that the factory pressure is 30 psi. Is that the same thing?
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Old 06-14-2016, 07:49 PM   #6
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Re: Decreasing water pressure


If you listen to the incoming pipe from the well, you can hear the water running, which only occurs when the pump is pumping. This assumes you have a submersible pump in the well. The pressure switch is usually immediately above the well T, which is usually a copper or brass fitting with the inlet from the pump, the outlet to the house, a sillcock to drain the lines, and a connection to the pressure tank. So it is usually a 4 way fitting.

The pressure switch is usually on top of a small tube, often brass, which is usually about 3/8 inch diameter, and sticks up a few inches above the well T. The tube transmits water pressure to the pressure switch, so the switch knows what the pressure in the line is. The switch is almost always adjustable, you have to take the top off, then you can see the contacts, and there is usually an adjustment device to change the on and off pressure. Be careful if you pull the top off, most pumps run at 240 volts, and the contacts are live, so you can get a hell of a shock if you touch them. Best to turn off the pump (there should be a pump off switch near the panel) before you try to adjust the on off pressure.

Usually the pressure tank is set within 2 psi of the pump on pressure, so in your case if the tank is set to 30 psi, the pump is supposed to turn on at about 30 psi. Usually the pump is set to turn off about 20 psi above the cut on pressure, so your system sounds like it is set for 30 psi on, 50 psi off, which is pretty common.
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Old 06-18-2016, 07:18 AM   #7
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Re: Decreasing water pressure


I haven't had a chance to pick up the gauge yet. But I went to do a load of laundry just now and the water pressure drops almost immediately. And I can hear water coming in from the well. The dryer is right next to the tank and the gauge on the tank faces, you guessed it, the dryer. Since my head isn't 1" thick, I stuck my cell phone down there to try to take a picture of the gauge to see what it read but it was too dark for a photo.

Does this help narrow things down?
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Old 06-18-2016, 06:46 PM   #8
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Re: Decreasing water pressure


If the pump comes on on immediately when the water is used that would indicate a problem with the pressure tank being water logged.
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