pipe corrosion

Hi, guys:
I am new here as well as to plumbing. Just recently I noticed a white fluffy residue on the main shutoff water valve in the basement (dezincation?). My question is when I should start to worry about the potential valve breakage? Or should I replace it ASAP? The house is 24 years old, the valve was used last time about 6 months ago and it worked fine. I am going away for several weeks soon. Would it be safe to leave it as it is (hoping that, as nobody uses water, nothing will happen)? Or should I take care of it before leaving?
Thank you very much for your advice. Olga

Without seeing it, it's hard to tell for sure...it could be mineral deposits from a very slow leak. Maybe post a picture.

Olga, Murphy's Law, I live by it. I would get a plumber in, have him or her look at it, and take it from there. Better safe than sorry because what is peace of mind worth?

de-zinc is usually related to the quality of the brass, and a brass valve from 24 years ago was probably made in the US of good materials.

Jimbo -

Mind I ask. Do you , as a pro, care what COO the materials you are using.
Whether it be charlotte CI pipe, can't think of any USA tubular stuff except for Wolverine brass , usa made flex hoses, etc......

I try to buy domestic where I can and sometimes will even go out of my way to buy domestic products...
Don't even ask how large my stash of Dahl valves are ;-)

Harder and harder to find US made stuff.....customers don't want to pay the price!

I'm a little fuzzy on it, but from what I recall of process work, dezincification shows up as leaks through the wall of fittings and tubing typically--creates thin walls that are porous. As jimbo says good alloys don't tend to have this problem, more recent Chinese stuff might because their experience is lacking and their standards have been so lax. You can't trust that the Chinese have used the correct materials or proper manufacturing technique in my experience (both working with them industrially and as a consumer. I had one clueless Chinese engineer that I finally stopped taking calls from...only time I've ever done that.)

Any sort of slow leak can give a fuzzy/crusty surface around a fitting. Packing leaks are common sources of this and might even seal themselves. If they don't seal themselves you can tighten the packing gland to seal the leak on some valve types--although not quarter turn valves as are typical of shut offs.

The question to ask is specifically where do you see the build up? If it is primarily around the main body of the valve then dezincification would be a reasonable fear and it should be examined and possibly replaced. If it is and either end then a fitting leak is most likely the culprit. If the leak appears to be around threads and isn't leaking at present it will likely be okay. However, if you identify a crack (such as in part of a union) then it should be replaced ASAP.

quote; customers don't want to pay the price!

Customers will pay whatever we charge. The MANUFACTURERS do not want to pay the cost of making them in the U.S.A. The valve will NOT spontaneously fail, but eventually it WILL break when you either turn it off or try to turn it back on. THEN, you can change it.

Thanks a lot, everyone. I have thought that it is not a mineral deposit as it is fluffy, not hard as I would expect a mineral deposit to be. This build up in on threads and handle, but the valve is currently not leaking. By the way, I noticed exactly the same build up on a water heater pipe intended for releasing water. And that water heater is only 5 years old. The Murphy's law always work for me, but from your answers I got a hope that the valve should hold on for a while. I am planning to get a plumber after vacations for some remodeling and will ask him/her to look at it then.
Thanks a lot. Olga

Scrape some of it off, stick it in a glass with some vinegar covering it...if it disolves in say a day or so, it is mineral deposition from the water (mostly calcium). If it is a zinc compound, don't think it will disolve in vinegar (a mild acid).

jadnashua said:

Scrape some of it off, stick it in a glass with some vinegar covering it...if it disolves in say a day or so, it is mineral deposition from the water (mostly calcium). If it is a zinc compound, don't think it will disolve in vinegar (a mild acid).

Click to expand...

Thanks a lot, I will try this today. Update: I have also noticed that when I turn on the washing machine, I can hear a dripping sound if I run to the main valve and stand next to it. This sound is heard for only 1-2 seconds and then disappears. But I could see no water on the valve, it is completely dry. It seems like the sound comes from behind the basement wall (it is "poured-in" basement). If it is a mineral deposit on the valve, does it mean that there is no leak in the valve itself but something is wrong with the outside pipe conducting water to the house? This dripping sound in ONLY heard at the moment of turning on the washing machine. Or, maybe, it is caused by the water pressure change and I should just ignore it? Please, advise.
Thank you. Olga

In order to be able to turn the handle on a valve to control the water, there is a seal in there along the shaft of the handle. On many valves, there is a nut and packing material configured such that when you tighten the nut, it compresses the packing (sealing) material to prevent it from leaking around the shaft. If that nut isn't tight enough, or the packing isn't 'packed' quite right, it might leak a little, especially after turning the handle. It might not be much. If it is an occasional drip, since most water has minerals, the drip leaks out, may not fall, evaporates, leaving the disolved minerals as a powder or buildup. THen, it all happens again, and again, making the deposits big enough to actually see.

IF that is what's going on, often, all you need to do is turn that packing nut slightly tighter, and it will improve the seal. If you tighten it too much, it presses on the shaft of the handle and it can become very hard to impossible to turn. Normally, you might only need to tighten it as little as maybe 1/16th of a turn - essentially, just nudge it a little tighter.

If the metal of the valve is degrading, disolving, from manufacturing defects, or possibly a casting defect (porous) that's an entirely different story. That could happen anywhere, while a packing leak typically would show up near the shaft/nut.

As to the WM supplies, sounds like one of those things that you'd have to be there to investigate in order to be able to supply a decent answer.

I'll tell you what Olga, if I was laying on the white sunny hot beaches somewhere, either in the US, or in NZ, I wouldn't want to either... a. Be thinking about the plumbing or b. Thinking about having to fix this when I am done vacationing. For now, you could get someone to check it out and enjoy the vacation instead of running over and listening to the main valve. Again, what is your peace of mind worth to you? I woudn't ignore a potential problem.