View Full Version : Copper in Domestic Water
11-01-2008, 12:25 PM
We have a house with unacceptable levels of copper in the domestic water. This was first apparent when a new filter cartridge became clogged . The local water company tested at the source (outside the house) and found normal copper content but found high levels of copper in both hot and cold water lines. Residue from the surface of the filter tested as copper. The house was build in 1985 with two hot water recirculating loops on two hot water tanks. There were no check valves between the hot water lines and the cold. These pumps ran 24 hrs and day. It has been suggested that they caused erosion of the copper pipe. Our questions: How do we confirm what the cause is and how do we get rid of the copper in the system?
It that is the real cause you should either HAVE leaks in the hot water system or are going to have them. But the hot water has nothing to do with the cold water so if both have the copper it is from a different source.
master plumber mark
11-01-2008, 04:44 PM
Like HJ said,, you should be having pin holes in your copper plumbing already....
you need to turn off the pumps to save what is left. of the lineing inside the copper pipe...
you can also get copper breaking down due to any kind of electrical ground to the copper that might be putting small amounts of electricity into the line and breaking down the copper...
if it is as bad as you claim it is, it probably is already too late and eventually you will have the pin holes in the system
might as well plan on re-doing the home in pex or new copper. and put the pumps on timers
Check the acidity level of your water. Anything lower than 6.6 will eat your pipes. Do you have a well? Most well water is acidic and requires a nuetralizer.
11-02-2008, 06:12 AM
The velocity of the water being recirculated could also be a factor.
High velocity can erode pipes.
11-02-2008, 12:28 PM
I agree with Redwood, recirculation and then the velocity can cause erosion of copper tubing.
Low pH and high DO (dissolved oxygen), TDS and chlorides content can also cause copper corrosion. Excessive soldering flux can also but I doubt that is the cause.
What is the copper content; both hot and cold?
What was the copper content coming in from the street? If the water company didn't tell you, have a copper test done on it.
If you don't have a copper service line from the street into the house, there shouldn't be any copper in the water coming into the house.
11-03-2008, 06:32 PM
Some more info:
The filter that blocked up is a Franke LB 2000 on a cold water line at a kitchen sink. Service to the meter is 3/4". Supply from the meter to the house is 1 1/4" copper. There is a new regulator (the old one had failed) set at 75 lbs. There are four baths, two kitchen sinks, and a laundry. Two to three folks in the house. I don't know about pipe markings, but I'll check next time I'm there.
The water company reported 0.1 ppm copper at the pressure regulator, 1.8 ppm in the cold water at a kitchen faucet, and 2.3 ppm in the hot water at the water heater.
We are a remodeling company working on this house. The owners have occupied it for only two years and were unaware of a water quality problem. Only a small amount of new plumbing work has been done in the course of the remodel: two new shower valves, relocating fixtures in the remodeled kitchen, the new regulator, and replacing the failed recirc pumps and adding check valves and expansion tanks at the water heaters. Work was done by a licensed plumber. The replacement pumps were sized based on the original pump model number. The plumber is looking into whether this is appropriate sizing but the pumps did not seem unusual for this purpose at the time he did the work.
Our work was almost complete when the owner reported reduced flow from the new Franke filtered water dispenser which led to the discovery of copper in the water.
Another question: Having determined that the problem resides in the house the water company will do no further testing. Whatever remediation is ultimately tried, we need to verify its effectiveness by testing for copper. Who does this kind of testing?
11-03-2008, 09:22 PM
A water company will not test the water from a new house for copper rule compliance until the house is 5 years old. That's because new copper tubing has no protection from the water, like a green patina or microscopic layer of hardness scale and until then the copper level can be too high to meet the max amount allowed.
Another good probability of a cause is excessive soldering flux, it corrodes copper tubing adding copper to the water.
Any lab or some water treatment dealers can do a copper test or you can buy a test kit from www.hach.com (http://www.hach.com).
Soldered with No-Lead Solder