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one hot water tap running cloudy white

it seems to be mostly air, but it is the tub filler with no aerator and the cold does not do it, nor any other hot water taps. It's enough to be noticeable in the stream of water running from the tub which caused the tenant to call. Run into a jar It looks almost milky and then slowly clarifies from the bottom up leaving no apparent suspended solids or precipiate. seems like some kind of micro air bubbles. The tub spout is fed by an old (50 year) twin handle set that is separate from the shower valve although the shower water runs through the brass body at the back of the tub valve set.

Took the stem out and no obvious corrosion or particulates in the assembly. The tenant now thinks they smell something when the shower is on although you don't get the same cloudiness if you capture the shower water and this is an urban water system where the water smells like chemicals to me anyway since i have untreated well water. But there is nothing like it happening at any other spigot or faucet throughout the house.

I just am not sure how to explain or mitigate the effect. I have seen mildly similar if markedly less complete effect filling a glass from a faucet with an aerator but I really don't know what i'm dealing with.

This is the link to a youtube we made of filling a jar and waiting for it to clear which shows the cloudiness and the slow clarification from bottom to top of the jar:


thanks for throwing spaghetti at this wall - hope something will stick.



  • Jamie Hall
    Jamie Hall Member Posts: 22,100
    Sure does look like air bubbles to me. Is there anywhere between the hot water valve and the spout where there could be a leak which is somehow allowing air to be sucked in? As though it were an aerator? It could be a pinhole or a bad solder joint or I have no idea what -- but you wouldn't see it if the water weren't flowing. Maybe check by holding your hand to stop the water coming out of the faucet and turning the hot on?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Leonard
    Leonard Member Posts: 903
    edited February 2018
    I'm on city water too , I've seen that here when city replaced large dia under ground street mains several blocks away down the hill. Lots of air got into city mains. Guess pressure dissolves it into the water. Then when pressure is released (at tap) it micro bubbles out like you show. On my water pipes it went away in a few days, guess that's how long it took for all the air to get flushed out of street water mains.

    Been told hot water can hold less air than cold water, that's likely why cold tap doesn't do it. That or hot water tank is holding lot of air?? Also aerator might mist water enough that it's easier for air to dissolve out of small mini-drops of water.

    I see same thing when I drain condensate water out of my 150 psi air compressor tank (tank is at 150 when I drain) . But the bubbles are even smaller, can't see individual bubbles, it looks like milk, then after few minutes the air comes out and it's clear.

    Don't see how a pin hole in pipe would make this happen, as that would be an outward leak of water, not an inward leak of air ( against water pressure). Assumes water pipes are always pressurized.
  • archibald tuttle
    archibald tuttle Member Posts: 1,043
    jamie / leonard.

    i'm familiar with the ability in some circumstances and design of piping that flowing water could entrain air despite the fact that in theory it exhibits pressure everywhere. but i would figure that either it is a part of the piping that is not under constant pressure or i would have a drip leak when the water was moving. there is no aerator, this is a tub spout. I suppose there could be a very tiny passage around the o-ring in the stem that only manifests when the valve is open so you don't have water pressure on the stem seal except during valve open. maybe i'll silicone grease the crap out of the o-ring or get a new one or both and see if i get any different result.

    since the effect seems so related to one valve on one faucet that is at least a plausibility although the pressure is lowered it would stil be positive around the stem i would think, but perhaps at lower pressure circumstances with the flow involved it has some way to create suction that is pulling in the air. it is one of those old american standard aqua-seal setups although it has been updated with the redesigned stem that uses standard faucet washer, but the o-rings in the original and replacement stems are quite thin in cross section but since i didn't see any weeping out of the stem i didn't suspect that as a problem.

    my other choice, if replacing stem seals doesn't stop the effect, is just to take that valve set out of the piping (go around it with pex up to the shower valve. Thus I have stopped the 'problem' so the tenant feels we have done something and they largely use it as a shower anyway and could fill the tub with the hand shower if they really wanted to.

    I don't blame the tenant for wondering why the water is milky, but short of some expensive testing regime to demonstrate that its no different than the clear water coming from other taps I'm thinking it is easier just to eliminate the damn tap causing the trouble since it is only marginally necessary what with the not too generously sized bathtubs associated with these shower tub combos seeing little use in this day and age.

    thanks for your thoughts, and any others that trickle in . . .

    JUGHNE Member Posts: 10,898
    Could it be that when the hot water is running out the tub spout it might be drawing air in thru the shower head?
    A simple non invasive test would be to remove the shower head and cap the arm with 1/2" pipe cap.
    If it clears for this then loosening the cap allowing air in would cloud the water flow again. Just simple test.
  • archibald tuttle
    archibald tuttle Member Posts: 1,043

    not a combined tub shower valve. separate two handled aquaseal for tub, symmons temptrol shower only valve above. so don't think that could be the phenomenon.


  • Leonard
    Leonard Member Posts: 903
    edited February 2018
    Since it's city water call the water dept and ask (anonymously).
    They likely have seen it before, from air introduced into city mains during street water pipe replacements/additions.

    What I was trying to say was the aerator likely helps get excess air out of water by breaking water into fine drops with more surface area for it to dissolve out thru. Tub doesn't have aerator so nothing to help get air out quicker. At least that's my theory.
  • archibald tuttle
    archibald tuttle Member Posts: 1,043
    got it on aerator, so under this theory if it take the aerator off the sink i might see the same thing .i'll try it. thanks
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,137
    Hello, A remote possibility is that the shape of the plumbing from the water heater lest gas float up and collect where the tub then flushes it out. Does the water clear after running for a minute or two? Anyway, if it's from the water heater, it could be hydrogen gas from the action of the anode that you are seeing. Very hard or softened water can speed up the anode and create gas that appears daily, particularly on first use in the morning.

    Yours, Larry
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,840
    Carefully light a match or a lighter near the jar opening while it is dissipating the gas. If it POOFs, it's hydrogen and as Larry noted, probably a by product of anode degradation.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • HomerJSmith
    HomerJSmith Member Posts: 2,309
    Flow occurs from higher pressures to lower pressures in any liquid or gas, or to put it another way from higher densities to lower densities. You're not going to be sucking air into a higher pressure.

    Cold water holds air in solution better than hot water. As water is heated air moves out of solution, forming first micro-bubbles that coalesce into larger bubbles that are more visible. Micro bubbles form when there is a pressure change, too.

    "...although you don't get the same cloudiness if you capture the shower water..." Shower water is in fine sprays which makes it easier for the gases to exit the water before you collect it, so there would be a difference in what you see.

    "But there is nothing like it happening at any other spigot or faucet throughout the house."--That's troubling. I would expect it to be present at any other hot water faucet, too. Micro bubbles form when there is a pressure change, too.

    Is it a personal well or is it a municipal well? Municipal entities could be working on the water system or submersible pump or surface pump could be entraining air in the system.

    If the gas does turn out to be flammable, I would ask are you living in a fracking zone where oil fracking is going on? Sometimes odors can be psychosomatic although the sense of smell is one of the most powerful of the senses. It's wired directly into the lymbic system.

  • archibald tuttle
    archibald tuttle Member Posts: 1,043
    thanks for that thoughtful rundown. this is municipal water system in large urban setting with a motley crew of varied pipes in the street from old oak mains to cast iron, concrete lined and some modern plastic replacement.

    the tenants haven't been able to really well describe the 'smell' and honestly i think because it is experienced in the shower it has the character of some of this air coming out of the water stream and smelling like treatment chemistry of which EPA and our antiquated system guarantee us quite a bit.

    That said, my confusion continues because i really don't see much of the effect if I take the shower head off and run the shower. I understand that the shower head would break up the stream and help get rid of trapped air but i've tried it without the showerhead and i see nothing like what i see coming out of the tub making me wonder if, despite theoretical objections, there could be something about the tub valve itself. how it could be possible to create some kind of low pressure venturi or entrainment around the tub valve, since the water is never, at least as i consider it in theory, at less than air pressure, I remain mystified.
  • archibald tuttle
    archibald tuttle Member Posts: 1,043
    mark and larry. interesting on anode effect and possible hydrogen. i will certainly try the combustibility test. the thing that seems strange to me is that we would be there running and testing for half hour and the effect never went away. now we didn't run it for a half hour straight. but we ran it a fair amount. I don't know if this annode on steroids affect could actually be producing gas while you wait, so to speak.

    This is a fairly high and central outlet although I would think I would see it in the shower (with the head off) as much as at the tub if this were just the natural place to which an effect originating in the hot water gravitates (or really the opposite of gravitating).

    Thanks you both for taking the time to think about and write these ideas.
    Mark Eatherton
  • Leonard
    Leonard Member Posts: 903
    edited February 2018
    Do a test. From sink with aerator fill a glass with water. see if it's cloudy. If not , dump the glass , remove aerator and refill the glass. If it's now cloudy , then it's likely the aerator removed the gases. To make sure it's not random gas , reinsert aerator and repeat.

    If you really want to be certain it's not random chance repeat test about 10 times in a row. Seriously!

    If you can make the problem come and go at will ( 10 times) then your pretty certain you have found the cause. (engineering method when dealing with odd new stuff we've never seen before)