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I'm polling my peers regarding lead concentration in residential water piping

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MikeL_2
MikeL_2 Posts: 557
in Pipe Deterioration

A long time customer discovered high lead concentration in his water during a test needed for the sale of his home.

He has elected to replace his copper piping that was installed with lead bearing solder in 1980; the water test was clean at the well water tank.

Is there any reason to replace the hot water piping? Or the piping to toilets? The water PH is 6.9..…

Comments

  • mattmia2
    mattmia2 Posts: 18,254
    edited October 23

    probably cheaper and would make everything last longer to add treatment to raise the ph instead.

  • hot_rod
    hot_rod Posts: 28,544

    I would do a lead retest. 6.9 is not very aggressive to metals. Below 6.5 is where it can be a problem.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Jamie Hall
    Jamie Hall Posts: 27,911

    If the lead retest still comes back as too high… you can try to see if the pH can be reduced, but there are two problems with that: a lower pH is going to attack the copper, and you will have a different problem. So… yes, he may need to replace the copper piping. ALL of it. Hot water and cold both, and there's not much point in not doing the short takeoffs to the water closet.

    However, before he goes to that trouble, check two other things: look everywhere in the main coming in in the basement. Is there any chance that that might be an old lead pipe? It's happened. And also, if at all possible, check the material of the pipe from the well to the house and the drop pipe in the well. But with the water test at I presume the pressure tank in the hose — not likely to be those.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • hot_rod
    hot_rod Posts: 28,544

    probably more potential to get lead leaching from any of the faucets, in the 1980 vintage

    PRVs, backflows, shutoff valves, angle stopd, etc any brass in the piping would be leaded back then

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • EBEBRATT-Ed
    EBEBRATT-Ed Posts: 21,190

    Doesn't the water have to sit in the copper pipes for some time to start leaching?

  • mattmia2
    mattmia2 Posts: 18,254
    https://forum.heatinghelp.com/discussion/comment/1907430#Comment_1907430

    i'm thinking it was sitting vacant for weeks or months and they just put whatever had been sitting in the pipes or fixtures for weeks in the sample jar.

  • hot_rod
    hot_rod Posts: 28,544

    Copper tube and fittings tend to develop a patina on the inside. Minerals in the water put a coating on the pipe which protects the system and eliminates solder leaching

    Unless you have aggressive water an or excessive velocity, copper piping pretty much protects itself

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Larry Weingarten
    Larry Weingarten Posts: 4,205

    Hi, I'd want to know more about the test that was done. Was it a first draw test, where the first water drawn after sitting overnight is tested? If using older brass faucets, this could be the source of the lead. I might retest, using first draw and then water from the same tap after running for 30 seconds or so. If the second test is clean, copper replacement is a waste and just older faucets should be looked at for changing.

    Yours, Larry

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