Air discharge at a sink faucet may be normal or it may be a problem (C) Daniel FriedmanAir Eliminators & Vents
Use an Air Eliminator to Remove Air Bubbles in Water & Stop Air Discharge from Plumbing Fixtures

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Use an air eliminator device to fix air bubbles in water or air coming out of faucets:

This article describes cures & devices for removing fine air bubbles in the building water supply, bubbles in hot water, or air discharge at plumbing fixtures. After reminding you to make the correct diagnosis of the cause of air in the potable water supply, we list devices and approaches to removing it or preventing its entry in the first place. At page top: our photo shows fine air bubbles in the discharge at a sink faucet. These may be normal or they might indicate a problem.

This article series 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.

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Cures Air Bubbles in Water or Air Discharge Bursts at Plumbing Fixtures

Bladder type water tank (C) Daniel FriedmanTypes of Air Eliminators for Potable Water Supply Systems

[Click to enlarge any image]

Reader Question: how to get rid of fine bubbles in water from a deep water well

2016/06/08 Mike P said:

We have very deep bedrock well - 385 ft deep. It produces 16 GPM. From the beginning the water has been full of small bubbles. I am almost certain the bubbles are not mechanically produced as they occur when water is drawn directly from the well manifold before reaching any of the faucets and filtration systems. There are so many bubbles when water is drawn from the manifold it is milky white, not just cloudy. It takes well over a minute for a 20 OZ glass of water to clear.

When the bubbles dissipate the water is crystal clear. If I put my ear to the glass I can hear the effervescence of the bubbles releasing. I don't believe there is a problem with the pump. The water pressure is outstanding and the entire water system is new. Again we have had this problem from the very beginning ~ 4 years ago. It seems most likely there are gases dissolved in the water under tremendous pressure and cold at 385 ft below surface.

The gas is not methane (won't ignite) and has no odor. It seems unlikely it is radon as we have been living here for 5 years with no ill effects. We have installed a pressure relief valve right after the manifold but I believe the water passing the valve does not have enough time for the gas to release at that point.

There is so much air/gas in the water that our toilet on the upper level of or home (highest release point) sputters as the gas is released through the toilet valve. Initially we thought the problem was related only to hot water but obviously the toilet does not run on hot water.

I have read that installing a "holding tank" for the bubbles to release before water enters the water system may be one solution. I'd like to avoid that if possible as I have limited space in my mechanical room. Would it make sense to install a pressure release valve at the upstairs toilet as that seems to be where the air pressure "wants" to release? Any other suggestions?

Reply: causes & cures of fine air bubbles in water from a deep well


I've seen these ultra-fine bubbles in water in both private wells and public water supplies, and it's a common problem discussed among well installers and plumbers. When I see a murky white mist in the water supply at the tap, first I confirm that it's air, not sediment by filling a clear pitcher of water and watching to see the bubbles disappear. That may take time, from one to even five minutes or more.

Leaks at brass fittings on plastic water supply piping (C) Daniel Friedman

Watch out: First be sure that we have correctly diagnosed the cause of fine air bubbles in the water supply or of air bursts or discharge at faucets or toilets or shower heads. See AIR DISCHARGE at FAUCETS, FIXTURES where we list the causes of air in potable water piping or at fixtures - a problem that can occur on both well water systems and municipal water systems. Our photo above illustrates pinhole leaks in brass fittings on plastic water supply piping.

Your argument that bubbles come from dissolved gases is an interesting and credible one Mike and one that we need to discuss in more detail.

At GASES in WELL WATER we introduce the topic and list common gases (besides methane or radon) that may be in your well water.

At 450 feet we certainly could have gases in water that change from dissolved to bubble state when the water reaches the surface. At any depth below about 30 feet the pressure is greater than 1 atmosphere and we begin to see problems with gases that are dissolved in water. SCUBA divers understand very well the problem of "the bends" - a dangerous illness that can occur when gases dissolved into the blood (from breathing pressurised air at depths below 30 feet) emerge when the diver ascends to the lower ambient pressure of the surface.

Pressure relief valves for air bubbles?

You suggested installing a pressure relief valve to address this problem in your plumbing system. A typical water system pressure relief valve shouldn't have any effect on the bubbles: that type of valve on a water system opens at pressures higher than the tank is intended to survive. But your pump's pressure control switch is stopping the pump well before the water pressure exceeds the tank pressure (unless someone has done something unsafe and unusual). So a conventional water pressure relief valve or even a temperature/pressure relief valve won't act as an air eliminator.

Holding tanks for removing air bubbles?

A simple water pressure tank or water holding tank alone, without additional key devices, may accumulate air but eventually that accumulated air will reach enough pressure to emerge at plumbing fixtures where it can be annoying at best.

The holding tank solution presumes that water has enough time in the tank (basically a larger pressure tank) for gases to exit the water; older pressure tanks that use an air volume control rather than an internal bladder will release excess air (or gas) through the AVC automagically; newer water tanks that use an internal bladder will accumulate air until its pressure and volume send it out through the house piping. Thence it's reaching and misbehaving at the toilet; you might also see air discharge at faucets as we discuss in the article above.

What we both should look for is a float-operated automatic air purger or a model of the Honeywell Spirovent that also purges air and may be longer-term more reliable. At a convenient location (or more than one if experience shows its needed) you'd install a tee in a horizontal line, a vertical riser pipe of a height that's convenient and fits - perhaps a foot or two - topped by the automatic air purger. The principle is that actual air bubbles flowing along with water in the horizontal line will move up through the tee and out at the air purger.

Heating system type float valve or spiro-valve air purgers?

You can't use a standard heating system automatic air purger, as those valves typically tolerate pressures only up to 40 or 45 psi. So we need to find a model that operates in the pressure range of your water system, or perhaps between 20 psi and 80 psi as I doubt there's a home water system that should be operating at pressures higher than that.

Take a look at the Spirovent from Spirotherm, or their Spirotop, a solar application that is specifically designed to elminate micro bubbles. Spirotherm, Inc. The company's product literature doesn't seem to mention the PSI operating range. Some solar systems operate at relatively low pressure so the operating pressure range is a key question to ask. If this product isn't suitable and the company can't recommend one that is, we'll look further.

Heating system air purgers are needed to prevent loss of heat from air-bound heating piping or boilers, radiators, or baseboards. That's because a conventional hot water (hydronic) heating system circulator pump can't reliably push large boluses of air around through the loop of heating piping. Details about these devices are at AIR BLEEDER VALVES [for heating systems] - but that's not what you want for air in the potable water supply.

Devices & Suggestions for Air Elimination from the Potable Water Supply: get rid of unwanted bubbles or air bursts at fixtures

Lancaster Air Elimination Tank Installation - Lancaster Water Treatment Co. adapted by 2016

Above: an example of an air eliminator tank installation, adapted from Lancaster Water Treatment Company's instructions for their Model 230-1248 Air Eliminator Tank. Contact information is given just below.

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APCO's combination air valve (ASU) - see - at

Above: APCO's Combination Air Valve described just below.

Remove Air in the Water Supply or Find & Fix the Cause?

It's worth asking for help from an expert water supply systems plumber or well contractor to do what you can to find and fix any leak or mechanical problem before treating the remaining symptom with an air removing system. I don't love the idea of leaving a leak in well piping or equipment to fester as I worry that it may grow in size and impact, being temporarily covered over by the "solution" we added-on to the system.

Article Series Contents


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