Submersible pump well schematicHow to Diagnose & Repair Air Discharge from Water Supply Piping or Plumbing Fixtures
     

  • AIR DISCHARGE at FAUCETS, FIXTURES - CONTENTS: How to diagnose & fix sputtering air coming out of faucets. Causes of air blasts or bubbles in water supply piping & causes of excess air in water pressure tanks. Excess air in the water pressure tank or well piping system: causes and cures. Significance of large bursts of air at faucets & Significance of fine white bubbles in water taken from a faucet. Signs of loss of well water & Signs of well piping leaks. Signs of water pump failure. Water pressure tank air volume control problems: How to restore lost air in a building water pressure tank. What is a snifter valve used on a well water system and how do they work? Hidden and antique air volume control valves and features can explain well pump rapid cycling problems & air discharge troubles at faucets & fixtures
  • POST a QUESTION or READ FAQs about air discharge at plumbing fixtures and/or excess air in water pressure tanks or in well water systems
  • REFERENCES

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How to diagnose & fix air coming out of faucets:

This article describes the causes of air discharging from building water supply piping or plumbing fixtures or the sources of excess air in water pressure tanks, water supply piping, or other plumbing fixtures.

If air blasts out of your faucets or fixtures we explain what's going on, why it's a problem, and how to diagnose and fix the trouble. Some air discharge or bubbling issues in building piping are not serious, while others could spell expensive trouble. We list the various causes of air discharge at faucets or shower heads and how to correct each one.

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Causes of Air Discharge from Building Plumbing Fixtures

Air blasts or air bubbles coming from plumbing fixtures such as faucets, showers, or toilets may be a temporary problem that cures itself or it may be a sign of a deteriorating water well. Here we list various causes of air in building water supply piping and fixtures to help in diagnosing and repairing this problem.

Question: Why is air coming out of my faucets, what does it mean, and what can I do to diagnose and fix the problem?

For a couple months now we've had excessive air in our water lines, similar to after there has been a power outage and the water spurts out of the faucets. I'm trying to figure out a solution to our water issues. We continuously have air in our water supply at all faucets, toilets, and showers; the air is intermittent, and spurts out while water is running, anywhere from immediately after faucet is turned on to a couple minutes later (in shower, for instance).

Flushing the toilet results in the pipes or toilet valve banging. we have a well that's 204' deep, and the submersible pump was replaced in July 2005 (five years ago).

Our water pressure tank is working fine, turning on/shutting off at 30/60. After shutting off, with no water running, the pressure holds steady at 60. When the pressure tank is drawing water from the well, you can hear and feel the pipe from the well drawing in a lot of air from the well the cold water has the air problem much more than the hot water for whatever reason (please advise!), on two of our faucets with separate hot/cold handles, the cold water won't come out anymore.

Did the spurting of the air/water lodge mineral deposits in the valve or something to prevent cold water from coming out, but allowing hot water to flow? the flow rate out of our faucets varies from normal at times to very low pressure we don't have a water treatment system we don't have a venturi valve that I know of (we bought the house 5 years ago) or that I can find

I don't know the static level or the recovery rate of the well, and with our air/water problem, I'm not confident that I'd get a good reading.

A licensed plumber came out yesterday (very kind, offered a free estimate) and looked at the pressure gauge on the pressure switch (between the incoming supply line from the well and the pressure tank) and concluded that it's something to do w our well or well pump. He suggested that either the well may be running dry or that the screen may be clogged up. He suggested I get some friends and pull up the well pump and examine it. - T. C., Purcellville, VA

Answer:

From your description it sounds as if your well water level is dropping and the pump is sending a mix of water and air into the building piping. If that turns out to be the case, it might be possible to increase the well yield - a step less costly than drilling a deeper or new well.

But first take a look through the causes of air in building water piping that we describe just below. If the problem were simply a leak in the water piping between well and house, for example, that would be less costly to repair.

List of common causes of air in water, or air coming out of plumbing faucets and fixtures:

Consider that because under normal conditions building water supply piping and fixtures are pressurized with water, a leak or opening in a pipe or fixture would be expected to leak water out, not air in to the plumbing system. But there are some exceptions that we describe below.

Air blasts, or air sputtering out of plumbing faucets means there is air in the water supply system. Below we diagnose the most likely causes and thus the cures for this problem.

Article Contents

Watch out: a hole or leak in a well pipe or a defective or improperly installed check valves on a private pump and well system can also cause air discharge from the building's faucets. A faulty check valve that allows water to drain back into the well causes negative pressure or "suction" that can draw air and contaminants into the well piping or into the well itself. See details
at CHECK VALVES, WATER SUPPLY.

Experts note that when the pump shuts off, if there is a hole or leak in the well piping, the hole allows air into the well line; when the pump is running, water sprays out of the same hole, possibly adding to rust and debris in the well and the pumping of silty or dirty water into the building.

Why Air Overcharge in the Water Pressure Tank Can Cause Air Discharge at Plumbing Fixtures

Photograph of a water pressure tank air volume control


If in placing an air charge into a bladderless steel or fiberglass water pressure tank the tank is overcharged air may flow out of the tank, through piping and out of plumbing fixtures when water is turned on.

This condition only occurs if the tank is one that does not separate water from air using an in-tank bladder. In this case the problem is self-correcting, typically in just a few minutes of running water at each fixture, as excess air flows out of the tank, through piping, and out at fixtures.

As the water pump cycles back on and water is pushed back into the water tank, operations will resume normally.

For details see WATER TANK AIR, HOW TO ADD

and WATER TANK AIR HOW MUCH TO ADD.

How a Burst Water Pressure Tank Bladder Can Cause Air Discharge at Plumbing Fixtures


If a "captive air" bladder-type water pressure tank has a ruptured bladder, depending on the total air charge or pressure, air may be forced out of the pressure tank and through piping and fixtures as above. As with our first example, the air flow will be temporary.

Bladder type water tank (C) Daniel Friedman

But in this case the water pressure tank will become waterlogged and the water pump is likely to be short-cycling before long
See WATER PUMP SHORT CYCLING).

A new water pressure tank or a bladder replacement will be needed. We discuss captive-air water tank bladders, their maintenance, bursting, and repair,
at WATER TANK BLADDERS & CAPTIVE AIR.

How a Bad Check Valve can Cause Air Discharge at Plumbing Fixtures

A defective or improperly installed check valve on a private pump and well system can also cause air discharge from the building's faucets. A faulty check valve that allows water to drain back into the well causes negative pressure or "suction" that can draw air and contaminants into the well piping or into the well itself.

See details at CHECK VALVES, WATER SUPPLY.

Watch out: when diagnosing the cause of air discharge from building faucets, it's easy to misdiagnose the cause: from inside the building the symptoms of a bad check valve (loss of prime, possibly air discharge at plumbing fixtures) can look a lot like a hole in the well piping, especially if the hole is in the pipe rising inside the well itself (also causing loss of prime, air at faucets) - as we discuss further just below.

How Leaks in the Well Piping Can Cause Air Discharge at Plumbing Fixtures

Schematic of a shallow well single line jet pump water system (C) Carson Dunlop AssociatesExperts note that when the pump shuts off, if there is a hole or leak in the well piping, the hole allows air into the well line; when the pump is running, water sprays out of the same hole, possibly adding to rust and debris in the well and the pumping of silty or dirty water into the building.

While water piping is under pressure and water leaks out rather than air leaking in, if we have the combination of lost water pressure (for example during an electrical power loss or a well system being shut down), and leaks in the well piping, as water drains backwards into the well air may be drawn into the water piping through piping leaks.

If the piping leak is inside the well casing where plenty of air is available, and if the well piping includes a defective (leaky) foot valve or check valve in the well, this cycle could repeat and building occupants may see recurrent air discharge from plumbing fixtures.
See WELL PIPING FOOT VALVES.

You may be able to diagnose this problem by turning off all water supply in the building and watching what happens to the water pressure gauge at the pressure tank.

If the water pressure falls slowly even when you are sure no water is running in the building, there is probably either a bad foot valve or check valve in the well, or a leak in the water piping between the well and the building. But watch out - water pressure gauges can be inaccurate or slow to respond to changes in water pressure -
see WATER PRESSURE GAUGE ACCURACY.

If there is a severe well piping leak or a water piping leak or running plumbing fixture in a building the well pump may begin to run continuously - see WATER PUMP WONT STOP RUNNING.

See Water Supply/Drain Pipe Leak Types for details on diagnosing types of water piping leaks.

Also see PUMP PRIME, REPEATED LOSS of for additional diagnostic help with well piping and foot valve leaks.

How Loss of Water in the Well Can Cause Air Discharge at Plumbing Fixtures

A falling water table or decline in well recovery rate may cause the well pump to send a mixture of water and air into the well piping and building. If this condition is occurring you might notice that the air discharge at plumbing fixtures is intermittent: when no water has been run overnight and the well has recovered, once existing in-piping air has blown out, the water flow may appear normal, without air discharge.

But as well water level drops and the well is slow in recovering, the air discharge problem will return. In sum, these well or well and pump conditions can cause air to be delivered by the well pump into the building's water supply piping:

If your WELL YIELD DEFINITION is inadequate (inadequate WELL FLOW RATE) water level in the well may drop low enough for air to enter a submersible (in well) pump or into the foot valve.

The combination of a too-small STATIC HEAD, WELL DEFINITION (water reserve) in the well and a poor flow rate make this problem more likely. A well that has performed adequately in the past may no longer have an adequate yield for a variety of reasons: drought, a drop in the water table, drilling of new wells nearby, or yield loss due to mineral clogging of rock fissures that feed water to the well.

If the well pump is too large incapacity (pumping rate) for the well's safe yield then air may be drawn into the well pump and water piping when the pump drops water level in the well too low.

The safe yield for a well may change if the water table drops. Then, if the well pump output rate exceeds the safe yield for the well, air may be injected into the building water piping and the well pump may be damaged.

See WELL YIELD DEFINITION where we define safe well yield.

See WATER PRESSURE STOPS, RETURNS - for symptoms of loss of water in the well and slow well recovery rates.

See WATER PRESSURE LOSS DIAGNOSIS & REPAIR for our complete article series on diagnosing loss of water or water pressure at a building.

Defective or Damaged Well Pump Can Cause Air Discharge at Plumbing Fixtures

It is possible that a failing well pump may introduce air into the water supply piping system due to cavitation (a vacuum forming inside the well pump mechanism), causing dissolved gases to come out of solution. Cavitation and air leaks into a water pump may be more likely with an above-ground jet pump and less likely with a submersible in-well pump that would be expected to be always submerged in water.

See WATER PUMP LIFE EXPECTANCY.

If a new well pump has been installed and is over-sized, the level of water in the well may be drawn down too rapidly when the pump is running, resulting in air entering the pump and being delivered to the building. This condition can also occur in times of drought or if your well is running dry.

Defective Air Volume Control Can Cause Air Discharge at Plumbing Fixtures

An air volume control device may be installed on some bladderless water tanks to attempt to keep the proper air charge in the water tank. If the air volume control is leaky or not working properly it may be overcharging the water tank with air. If this is the case the air discharge from plumbing fixtures will be chronic.
See WATER TANK AIR VOLUME CONTROLS.

Gases in the Well and Water Supply Can Cause Air Discharge at Plumbing Fixtures

In some areas gases, including potentially dangerous explosive methane gas, may leak into the water supply and may be delivered into the building water piping from a well.

Watch out: methane gas in well water is a pollutant and may be explosive. According to experts such as the New Hampshire Department of Environmental Services,

Methane at high concentration is explosive and thus there is a fire hazard if large amount of water with methane are used near an open flame in a closed space. The presence of methane gas in water can be simplistically detected by agitating a small volume of water in a plastic container in an outdoor location and attempting to ignite the gas released. Have a neighbor present when you try this testing.

If you have such a well you should contact your local department of environmental services and your building department.

Lowering the settings of the pump’s start/stop switch and/or providing an air release vent on the water storage tank at the high point of the stored water might allow this “off gassing” to occur at a point other than your faucet. Since this is a natural condition, and no damage is caused, there is no need to take any particular action.

Dissolved gases may also be present in water but would not normally appear as bubbles or air blasts at a faucet. These include radon, carbon dioxide, hydrogen sulfide (rotten egg smell), or other gases from dissolved organic matter or chemicals. But in some deep wells water at the well bottom, at higher pressure, may hold dissolved gases that convert to bubble form when water pressure is reduced to ambient air pressure at building faucets.

Changes in water temperature also affect the amount of gases that remain dissolved in water - warming water drives gases out of solution.

See WATER POLLUTANT SOURCES

Air Discharge from Hot Water Faucets

Watch out: if you find air discharging only from your hot water faucets a dangerous condition may be present: the hot water heating system may be too hot, risking scalding or even water heater explosion. Turn off power or fuel to the water heater itself and call a licensed plumber immediately.

Problems with Water Treatment Equipment Can Cause Air Discharge at Plumbing Fixtures

Water treatment equipment can also inject air into a building water supply. Water treatment to remove odors or gases from the water supply may use venturi air injectors intended to remove iron, manganese, or odors. Properly installed these devices should not send air out of faucets. But the following conditions can cause air injector treatments to place excess air in the building water supply piping:

  • A change in the water pump output rate may cause a mis-match between the air injection rate at the injection nozzle or venturi and the total water quantity being delivered to the building
  • A change in water piping that fails to properly pitch water supply piping to an excess air relief valve
  • A failure of the excess air relief valve to continue to release air - the valve may need cleaning or replacement
  • An improper adjustment of the air-to-water ratio at the air injection nozzle or venturi. Your water treatment company technician can reduce the level of air injection to the minimum needed to remove the objectionable odor, iron, or manganese.

Other Sources of Air in Water Piping - Work on Municipal Water Mains or Private Well Piping

Site excavation (C) Daniel Friedman

There may be other causes of air discharge from building water supply piping, including the ones we list below.

  • Leaks in well piping anywhere between the well and the building can introduce air into the well piping and water supply system.
  • Temporary air introduction into municipal water supply piping when work is being performed on the water system. Usually such conditions are temporary.
  • Faucet aerators: Fine white bubbles in the water coming from a faucet may simply be due to the faucet aerator designed to prevent splashing.
  • SNIFTER & DRAIN BACK VALVES on submersible pump and well systems that use a bladderless water pressure tank (or whose bladderless water tank was replaced with an internal bladder water pressure tank) can push excess air into the water pressure tank.

If a bladderless water tank that used a snifter valve system is replaced with a new internal-bladder tank you may need to have a plumber pull the well piping to remove the (now no longer used) drain and vent found inside the well.

Even if the bladderless water pressure tank was replaced with a new bladderless tank, if the snifter valve system was left in place but the excess air vent was not installed on the new tank (or is not working) you'll want to provide or repair these components.

If your well tank is a "captive air" or bladder type pressure tank such as the Well-X-Trol™ series see WATER TANK BLADDER PRESSURE ADJUSTMENT.

Bladder type or captive-air water pressure tanks and their repairs are described at WATER TANK TYPES and at WATER TANKS HOW THEY WORK

 

Continue reading at AIR INLET VALVES or select a topic from the More Reading links shown below.

Or see

AIR VOLUME CONTROLS, WATER TANK

SNIFTER & DRAIN BACK VALVES

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AIR DISCHARGE at FAUCETS, FIXTURES at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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