Forum Discussion

Adventurer_Buck's avatar
Adventurer_Buck
Explorer
Aug 09, 2014

Foamy Water

Now and then we experience foam in the water in all the fresh water faucets.

We discovered why (in our instance) and wanted to share with the forum. Many posts regarding this occur when de-winterizing. We are not sure that anti-freeze causes this and it's more likly the process of de-winterizing and having an empty holding tank.

Recently, we started getting foamy water again. After thinking through where air could be introduced into the water lines (since we are miles and months away from de-winterizing), we gave credit to having just disinfected our holding tank and water lines. After that process, we drained the holding tank and did not refill it right away. Instead, went back to the water source (we had planned on refilling the tank when we left that stay). Apparently, we were drawing water from the faucet and taking air in from the holding tank simultaneously. Until now, we thought both water sources would be independent and not interconnected.

We are not sure if this is normal or just the way our system is working, but wanted to share what we found. After filling the holding tank with water (just partially to test our theory), the water stopped foaming. So, while on a water source, yet still having an empty holding tank, when using water, water (or air in this case) is also being drawn from the holding tank.

For those that experience this after de-winterizing, it would make sense that while flushing the anti-freeze from the lines, there's no water in the holding tank yet and that may be where the air is being introduced to the water making it foam???
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Aug 09, 2014
    If you are connected via a hose to your city water connection ALL plumbing lines in the system are pressurized even right up to pump discharge and fill valve to fresh water tank if you have one on water panel.

    So.......no place to suck air into that pressurized system.
    If there was an 'air' source it would leak water check valve in pump---water would leak back into fresh water tank, fill valve---water would leak back into fresh water tank, any other fitting etc---water would leak out)

    Think you just have some trapped air in system from recent disinfecting.

  • Adventurer_Buck's avatar
    Adventurer_Buck
    Explorer
    Aug 09, 2014
    Thanks for the diagram. That all makes sense if all's working as designed.

    So, it leads me to believe that we might have a bad check valve at some point in relationship to the holding tank..

    Stages of Discovery:

    - Disinfected, drained the holding tank and did not refill.

    - Began running off city water with holding tank empty. Water was immediately foamy when not foamy before.

    - Filled the holding tank and the foam immediately stopped.
  • Dave_H_M's avatar
    Dave_H_M
    Explorer II
    Aug 09, 2014
    I have noticed foaming for years after de winterizing when you would fill a glass of water. It always went away pretty quick - but I did not keep any stats on what pretty quick is.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Aug 09, 2014
    Adventurer Buck wrote:
    Thanks for the diagram. That all makes sense if all's working as designed.

    So, it leads me to believe that we might have a bad check valve at some point in relationship to the holding tank..

    Stages of Discovery:

    - Disinfected, drained the holding tank and did not refill.

    - Began running off city water with holding tank empty. Water was immediately foamy when not foamy before.Was not foamy before...prior to the disinfecting ?

    Now foamy cause there is/was trapped air in system

    - Filled the holding tank and the foam immediately stopped.


    If the check valve in your rv water pump was bad (leaking) the water from city water connection would go thru pump, thru check valve and fill your fresh water tank cause it is pressurized from the city water. It would not suck air back thru the check valve.
  • Adventurer_Buck's avatar
    Adventurer_Buck
    Explorer
    Aug 09, 2014
    Old-Biscuit wrote:
    Adventurer Buck wrote:
    Thanks for the diagram. That all makes sense if all's working as designed.

    So, it leads me to believe that we might have a bad check valve at some point in relationship to the holding tank..

    Stages of Discovery:

    - Disinfected, drained the holding tank and did not refill.

    - Began running off city water with holding tank empty. Water was immediately foamy when not foamy before.Was not foamy before...prior to the disinfecting ?

    Now foamy cause there is/was trapped air in system

    - Filled the holding tank and the foam immediately stopped.


    If the check valve in your rv water pump was bad (leaking) the water from city water connection would go thru pump, thru check valve and fill your fresh water tank cause it is pressurized from the city water. It would not suck air back thru the check valve.



    Was not foamy prior to disinfecting when holding tank was full or partially full.

    Cold water not foaming now after adding water to holding tank.

    Hot water still bit foamy which I'd contribute to holding the previously foamy water and to stay that way until it had time to flush fully.

    I understand your expalination of a bad check valve reverse filling the holding tank, yet that did not happen. The holding tank was empty until filled.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Aug 09, 2014
    AFTER you purge all the air out of system......opening all faucets hot/cold side, flushing toilet etc. etc.

    Go drain your fresh water tank.......you could even leave the drain open.
    Air is NOT getting into your 'pressurized' (from city water) rv plumbing system via an empty fresh water tank.
    High pressure goes to low pressure not the opposite.
  • DutchmenSport's avatar
    DutchmenSport
    Explorer
    Aug 09, 2014
    Did you also sanitize your water heater? If you did, it's possible you did not flush your water heater completely.

    I don't understand how no water in the fresh water holding tank would create foam, sucking air. Mine never has (all 3 TT's) and it's empty 99% of the time. Did you try running water from your fresh tank unhooked to city and see if you still get the foam?

    I just can't imagine your system sucking air anywhere. With pressure in the water lines, water will spew out, not allowing air to suck in. Same is true for your fresh water tank. Even if the check valve on the on-board water pump was broken, it would not suck air in, it would spew water out... back into the tank. Air and foam has to be coming from somewhere inside the system. I'd flush the water heater.
  • Adventurer_Buck's avatar
    Adventurer_Buck
    Explorer
    Aug 09, 2014
    DutchmenSport wrote:
    Did you also sanitize your water heater? If you did, it's possible you did not flush your water heater completely.

    I don't understand how no water in the fresh water holding tank would create foam, sucking air. Mine never has (all 3 TT's) and it's empty 99% of the time. Did you try running water from your fresh tank unhooked to city and see if you still get the foam?

    I just can't imagine your system sucking air anywhere. With pressure in the water lines, water will spew out, not allowing air to suck in. Same is true for your fresh water tank. Even if the check valve on the on-board water pump was broken, it would not suck air in, it would spew water out... back into the tank. Air and foam has to be coming from somewhere inside the system. I'd flush the water heater.


    Thanks to all for all the explanations and ideas on what might be causing this and for helping to trouble shoot the mechanics of the water system.

    Going to have to ride it out and see what comes of it all. We do know that if a cup is filled with foamy water, then allowed to sit, it does clear, so we know it's safe.

    Thanks again.
  • DutchmenSport's avatar
    DutchmenSport
    Explorer
    Aug 09, 2014
    Does it foam only at the kitchen sink, or does it also foam at the bathroom sink too. If only the kitchen sink, try removing the aireator (however its spelled) at the end of the kitchen sink faucet and see if it's still foam? If it does not, there's your problem. Which is really not a problem at all!

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