# Corrosion at supply pipes **URL:** \ **Category:** Plumbing Inspections\ **Created:** [July 15, 2008, 4:55pm UTC](https://forum.nachi.org/t/corrosion-at-supply-pipes/30070 "2008-07-15T16:55:45Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![dmacy](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/dmacy/32/1466_2.png) [@dmacy](https://forum.nachi.org/u/dmacy)\ **Post date:** [July 15, 2008, 4:55pm UTC](https://forum.nachi.org/t/corrosion-at-supply-pipes/30070/1 "2008-07-15T16:55:45Z")
What would cause just the water pipes to corrode at certain areas? No moisture noted in basement. ![122608 034 (Small).jpg](https://global.discourse-cdn.com/internachi/original/3X/f/5/f5263068365bd8d71c4165c9a85ec8f7db38d08a.jpeg) ![122608 032 (Small).jpg](https://global.discourse-cdn.com/internachi/original/3X/9/c/9cb204b050978dff2aca4d23ff07a3b46607e370.jpeg) ---
**Author:** ![mlarson](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/mlarson/32/89225_2.png) [@mlarson](https://forum.nachi.org/u/mlarson)\ **Post date:** [July 15, 2008, 5:03pm UTC](https://forum.nachi.org/t/corrosion-at-supply-pipes/30070/2 "2008-07-15T17:03:39Z")
Are the green ones hot? Chemical reactions tend to accelerate with warmer conditions. ---
**Author:** ![dmacy](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/dmacy/32/1466_2.png) [@dmacy](https://forum.nachi.org/u/dmacy)\ **Post date:** [July 15, 2008, 5:23pm UTC](https://forum.nachi.org/t/corrosion-at-supply-pipes/30070/3 "2008-07-15T17:23:18Z")
I was looking at that. The furnace humidifier is tied to the lines that are corodded. I thought it was the hot. ---
**Author:** ![jpope](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jpope/32/59425_2.png) [@jpope](https://forum.nachi.org/u/jpope)\ **Post date:** [July 15, 2008, 8:07pm UTC](https://forum.nachi.org/t/corrosion-at-supply-pipes/30070/4 "2008-07-15T20:07:33Z")
Condensation. . . It looks like excessive flux in some areas as well. . . ---
**Author:** ![dmacy](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/dmacy/32/1466_2.png) [@dmacy](https://forum.nachi.org/u/dmacy)\ **Post date:** [July 15, 2008, 8:47pm UTC](https://forum.nachi.org/t/corrosion-at-supply-pipes/30070/5 "2008-07-15T20:47:43Z")
What would your recomendation be? Insulate the pipes? The same home had glavanic corrosion and a leak above the water heater. I recommended a qualified specialist review the supply piping. There were 2 receptacles that the kids chalked and I wanted to make sure they were not messing with the plumbing.; ![122608 044 (Small).jpg](https://global.discourse-cdn.com/internachi/original/3X/9/e/9e2cb212f07b4c47c5f944e89bef3f771e50945e.jpeg) ![122608 033 (Small).jpg](https://global.discourse-cdn.com/internachi/original/3X/1/e/1eda4569db58ffceeef198a861b32ba4bd9d4dff.jpeg) ![122608 050 (Small).jpg](https://global.discourse-cdn.com/internachi/original/3X/b/6/b6caa0039ae13029017f1d9270bf6006794d471b.jpeg) ---
**Author:** ![rbrady](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/rbrady/32/980_2.png) [@rbrady](https://forum.nachi.org/u/rbrady)\ **Post date:** [July 15, 2008, 9:18pm UTC](https://forum.nachi.org/t/corrosion-at-supply-pipes/30070/6 "2008-07-15T21:18:50Z")
If you have contact between galvanized steel and copper pipe ANYWHERE on the system, you can get that corrosion in a different area. I find that many times if there is contact at one area, most of the corrosion will be near an area where the copper pipe is in contact with the ground or electrically grounded somehow. It looks like you have steel to copper contact at a duct (?) ---
**Author:** ![bkelly2](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/bkelly2/32/58257_2.png) [@bkelly2](https://forum.nachi.org/u/bkelly2)\ **Post date:** [July 15, 2008, 10:11pm UTC](https://forum.nachi.org/t/corrosion-at-supply-pipes/30070/7 "2008-07-15T22:11:39Z")
> [@dmacy](#): > > What would your recomendation be? Insulate the pipes? > > The same home had glavanic corrosion and a leak above the water heater. > > I recommended a qualified specialist review the supply piping. > > There were 2 receptacles that the kids chalked and I wanted to make sure they were not messing with the plumbing.; Replace all of the pipe hangers for a start. ---
**Author:** ![dbucknavich](https://avatars.discourse-cdn.com/v4/letter/d/ee7513/32.png) [@dbucknavich](https://forum.nachi.org/u/dbucknavich)\ **Post date:** [July 15, 2008, 11:17pm UTC](https://forum.nachi.org/t/corrosion-at-supply-pipes/30070/8 "2008-07-15T23:17:23Z")
> [@bkelly2](#): > > Replace all of the pipe hangers for a start. Good eye Brian ---
**Author:** ![jgilleland](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jgilleland/32/1326_2.png) [@jgilleland](https://forum.nachi.org/u/jgilleland)\ **Post date:** [July 15, 2008, 11:24pm UTC](https://forum.nachi.org/t/corrosion-at-supply-pipes/30070/9 "2008-07-15T23:24:27Z")
Nice catch Brian. If only the hot is reacting it is a chemical reaction that takes place only at a certain temp. The green (patina) comes from sodium or other salt reacting with the copper. This happens over time with all copper, look at the statue of liberty. In most cases it is not corrosive. ---
**Author:** ![bkelly2](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/bkelly2/32/58257_2.png) [@bkelly2](https://forum.nachi.org/u/bkelly2)\ **Post date:** [July 16, 2008, 12:21am UTC](https://forum.nachi.org/t/corrosion-at-supply-pipes/30070/10 "2008-07-16T00:21:48Z")
> [@jgilleland](#): > > Nice catch Brian. If only the hot is reacting it is a chemical reaction that takes place only at a certain temp. The green (patina) comes from sodium or other salt reacting with the copper. This happens over time with all copper, look at the statue of liberty. In most cases it is not corrosive. I believe Ralph pointed it out first. I just chimed in after. 😃 ---
**Author:** ![dbucknavich](https://avatars.discourse-cdn.com/v4/letter/d/ee7513/32.png) [@dbucknavich](https://forum.nachi.org/u/dbucknavich)\ **Post date:** [July 16, 2008, 12:33am UTC](https://forum.nachi.org/t/corrosion-at-supply-pipes/30070/11 "2008-07-16T00:33:03Z")
> [@bkelly2](#): > > I believe Ralph pointed it out first. I just chimed in after. 😃 Yeah, for some reason, I never listen to Ralph. 😉 Like I said, Good eye Brian. ---
**Author:** ![jgilleland](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jgilleland/32/1326_2.png) [@jgilleland](https://forum.nachi.org/u/jgilleland)\ **Post date:** [July 21, 2008, 1:33am UTC](https://forum.nachi.org/t/corrosion-at-supply-pipes/30070/12 "2008-07-21T01:33:17Z")
Sorry Ralph. ---
**Author:** ![rbrady](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/rbrady/32/980_2.png) [@rbrady](https://forum.nachi.org/u/rbrady)\ **Post date:** [July 21, 2008, 4:40am UTC](https://forum.nachi.org/t/corrosion-at-supply-pipes/30070/13 "2008-07-21T04:40:11Z")
I was just sharing my personal experience. If I see that type of corrosion, I pretty much always find copper to galvanized steel contact somewhere in the system. In the posted pictures I did see what looked like copper to galvanized steel contact at some type of sheet metal (second set of pictures). The other type of corrosion I see is due to excessive flux, but that is typically only near soldered joints. I haven’t really seen much patina type corrosion on copper which is not exposed to the weather. ---
**Author:** ![jmckee](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jmckee/32/211009_2.png) [@jmckee](https://forum.nachi.org/u/jmckee)\ **Post date:** [July 21, 2008, 1:40pm UTC](https://forum.nachi.org/t/corrosion-at-supply-pipes/30070/14 "2008-07-21T13:40:22Z")
Dave in looking at the first picture in the second set I’d have to ask is there a disconnected dryer vent near by?..the excess of hot moist air would speed along some of what You are seeing imo…jim