Copper is in ALL water supplies around the world naturally and is coming into your homes already in minute amounts.
it is a mineral, and the copper pipes in a home will not leech into the water in the pipes unless the water sits in the pipes for a very long period of time, which is unlikely in a home.
Scare tactics have been implored over the years about the dangers of this but in fact, our bodies need copper...maybe that's why God puts it in the water naturally
This is why we use RoDi....no need to worry about it then.
Copper from pipes is a known big issue to the EPA, and they set very high limits for potability (1.3 ppm) that can sometimes be exceeded. All you need to do is read enough water supply reports to know this is a concern, and 1.3 ppm is WHOPPING high for a reef. The EPA allows 10% of homes to exceed this level before an action is required. I agree that flushing helps. Does everyone do that before collecting water?
Copper is also present in some well water.
This is a section from an older article of mine with data to back up my assertion. I have not recently checked these same locations, and values today may be differen, but when I surveyed for the article, MANY cities had excessive copper in homes in their testing:
https://www.advancedaquarist.com/2004/1/chemistry
Toxic Metals In Tap Water: Copper
One of the biggest concerns for aquarists considering the use of tap water is copper. Copper is more toxic to marine invertebrates than it is to humans, so the EPA allows more in tap water than an aquarist would want in an aquarium. Specifically, the EPA has an action level at 1.3 ppm copper in tap water, and it is only a big problem (to the EPA) if more than 10% of the homes on the water supply exceed that level. For that reason, water supplies typically report the 90% level, meaning that 10% of homes exceed that stated value. Many also report the maximum level in any home tested.
Table 5 shows copper levels for a small selection of homes for all of the cities in this study. The reason that copper must be tested at the home tap is that most of the copper in public water supplies comes from the pipes in the home itself. Further, newer does not necessarily mean better, as fresh copper pipes might be even more inclined to release copper to the water than those that have had decades to build up protective coatings.
How much copper is too much? That is difficult to say, and certainly varies from organism to organism. In a
recent test,5 Ron Shimek added copper to natural seawater and looked at the effect on sea urchin larvae. He found that concentrations above 10 ppb decreased the larval survival after 48 h, and that concentrations above 100 ppb killed all of them. Whether that translates into particular copper levels to be concerned about in typical reef aquaria is open to discussion. Nevertheless, it points out that copper is potentially toxic at levels well below the EPA action level of 1.3 ppm. That hypothesis is well supported by the
literature on copper toxicity.6
Canadian Water Quality Guidelines for the Protection of Aquatic Life suggest that copper be kept to less than a few ppb in fresh water, but they do not provide a salt water recommendation.
So how do the water supplies stack up with respect to copper? For some homes, not well. Ten percent of the homes tested in Miami have more than 1100 ppb copper in their water. In Kansas City, Orlando, Phoenix, and certain districts in Houston, ten percent of the homes have more than 500 ppb copper. At least one of my neighbors in Boston has 1100 ppb copper.
What's the best case? That's hard to say for sure, but perhaps Central Arkansas, where ninety percent of homes have copper below 50 ppb. Nevertheless, ten percent of homes are above that level, and some may be significantly above that level.
Based on the data, if your home is among the highest in your district, your water likely will be unacceptable. Since most aquarists do not know the copper levels in their water, it can be a risk to use it. If you do choose to use it, there are some simple actions that you can take to help:
- Test the water for copper with a test kit. Some of the kits available to hobbyists (Seachem and Hach LP Cube, #21938-00), for example) claim to detect copper at fairly low levels (10 ppb for Seachem and 50 ppb for Hach). Whether those limits are attained in practice or not, I do not know. But they likely will easily detect the very high levels in some tap water (500-1000+ ppb copper). Thus they can at least be used to screen out the worst offenders.
- Let the water run for 5-10 minutes before collecting it. This will greatly reduce the likelihood of getting a high copper (or lead) level from water that has been sitting in your pipes for an extended period of time.
