What can cause air in home plumbing?

[D2Cat]

There is no odor at all. We do get blue deposits in the sink and toilets. I was told that is because of the magnesium content in the water around these parts.

Blue deposits could be from minerals in water, or I suppose wear on copper piping, but that seems pretty slim. Just make sure your wife isn't dumping some cleaning solution in anything.

 

[North Idaho Wolfman]

There are mutiple reasons you could be getting air in the water.

Do you have an in well pump or above well pump?
If it's an in well pump there should be at least 2 check valves, and the lower check valve can be failing.
You could also have this same setup on the suction line.
A leak or failure of these check valves will not be obvious and will cause air to get into the system.
A crack or leak in the well down pipe will not be easy to detect till you open it up.
If you do have a air bleeder on the hot water tank then you wouldn't notice any air in the hot water side as it's burping the air out.

If you do have sulfur gas or hydrogen gas in the system, they will both smell.
You could have carbon dioxide and that won't smell.

 

[lynnmor]

If you are going to flush the tank, just as well put in a new anode. Use your cordless impact to remove the thing easily. New anodes are flexible so if you don't have good headroom it doesn't matter. You'll already have the power off and water out.....

An elec water heater will last a LONG time if you keep a good anode in there.

Those hot dog string anodes are something to avoid, the hot dogs split and stop you from removing it as the harder you pull the more it widens. I wasted nearly a day fighting that junk.

 

[Flintknapper]

When the anode begins to fail there is usually a sulfur smell in the water.

A corroded anode rod could certainly allow for Hydrogen gas bubbles to form. However 'pure' hydrogen gas has no odor and the gas bubbles could be mistaken for air.

Worth checking out, but my suspicion is OP has leak somewhere in the suction side of the system (since he said the system holds pressure).

So principally....anywhere from the pump up to the holding/pressure tank. Most likely in the drop piping/connections.

 

[GrumpyFarmer]

It is just the cold water, not the hot water at all.

So I am not a plumber, but to me that means hot water tank functioning correctly and may be preventing the air bubbles from entering the hot line. That’s good, I think.

From there I would suspect chasing the water back the line goes to pressure tank and then to well pump. Do you have any faucets/taps between the pressure tank and hot water tank inlet? If so does that also have the bubbles? (That would tell you air entering before or after hot water tank). Not sure that helps much.

Seems like it is either pressure tank or well pump?

 

[Tughill Tom]

Sounds like the Foot Valve at the pump leaking down. Pull the pump and check.

 

[pigdoc]

I rented a house near a landfill for 6 years.
The well was deep ~500 feet.
Intermittently, 'air' would come out of the spout when the faucet was turned on.
At one point, the landlord was compelled by the Health Department to test my water.
Tech came out, and before sampling, he flamed the the spout.
WHOOSH! With blue flame.

Turns out, the 'air' in my lines was actually methane, a by-product of bacterial metabolism.
[The pressure tank/pump system in the house was ancient.]

Just a consideration.
-Paul

 

[McMXi]

Quite the mystery with lots of interesting possibilities. I hope we all get to learn the source of the gas, whatever the bubbles turn out to be.

Speaking of @armylifer's well and setup, I would have expected a cistern or holding tank in addition to a jet pump before the pressure tank. This is how my well is set up but as mentioned earlier it's not currently being used. The idea is to pump water from the well when the kW h cost is low to fill up the cistern, and then to pump water from the cistern to the pressure tank as needed. Perhaps this system is more important for a deep well rather than a shallow one.

I sure would like to have one of those wind mill pumps sitting over the well but from what I can gather, 550 ft is a no go for those iconic things.

 

[armylifer]

There are mutiple reasons you could be getting air in the water.

Do you have an in well pump or above well pump?
If it's an in well pump there should be at least 2 check valves, and the lower check valve can be failing.
You could also have this same setup on the suction line.
A leak or failure of these check valves will not be obvious and will cause air to get into the system.
A crack or leak in the well down pipe will not be easy to detect till you open it up.
If you do have a air bleeder on the hot water tank then you wouldn't notice any air in the hot water side as it's burping the air out.

If you do have sulfur gas or hydrogen gas in the system, they will both smell.
You could have carbon dioxide and that won't smell.

It is a submersed pump. I thought that one of the check valves was in the pump itself. I could be wrong about that but that is what I thought I was told. I don't know where the other check valve would be. I am going to check out all of the suggestions that involve above ground plumbing before I crack the well head. That will be the last ting I try.

 

[armylifer]

A corroded anode rod could certainly allow for Hydrogen gas bubbles to form. However 'pure' hydrogen gas has no odor and the gas bubbles could be mistaken for air.

Worth checking out, but my suspicion is OP has leak somewhere in the suction side of the system (since he said the system holds pressure).

So principally....anywhere from the pump up to the holding/pressure tank. Most likely in the drop piping/connections.

How many years would an anode last? The hot water tank is just 7 years old. I have never replaced an anode in a water heater before, and the water heaters typically last about 18 to 20 years before they have failed.

 

[GrumpyFarmer]

If the bubbles in cold water only how would the anode creating bubbles be applicable?