Copper: The Good, The Bad, & The Ugly

Over the years, copper has had something of a dichotomous reputation. One day it's good for you, the next you're advised to stay away from it. A news story might highlight its properties for bringing good health, whereas a follow‐up story might detail its link to everything from gastrointestinal problems to migraines.

Using copper pipe information

Copper – chemical element Cu, atomic number 29 – is a complex property. It's one of the few metals that can occur in nature in a directly usable metallic form. It occurs naturally in rock, soil, plants, animals, and water, and it may be this ubiquitous quality that gave rise to a few firsts:

  • It was the first metal to be smelted from sulfide ores (∼ 5000 BC)
  • It was the first metal to be cast into a shape in a mold (∼ 4000 BC)
  • It was the first metal to be blended with another metal, tin, to create bronze (∼ 3500 BC)

The element defies rash labeling. One must look at the good, bad, and ugly of copper to appreciate it fully.


The Good

Copper does the body good (in proper amounts).

All living organisms, including humans, need copper to survive. It works with amino and fatty acids, as well as with vitamins, to maintain normal metabolic processes.

According to the Copper Development Association, copper is essential to maintaining good health because it combines with certain proteins that act as catalysts for various body functions, such as making red blood cells, repairing connective tissues, and maintaining nerve cells and the immune system.

The World Health Organization (WHO) and the Food and Agricultural Administration (FAA) both have recommended amounts of copper that an individual may consume per day – usually no more than 12mg/day for adult males and 10mg/day for adult females.

Copper has antimicrobial properties.

Copper has been scrutinized over the past decade for its potential use in combatting infections. The Department of Defense sponsored a multi‐year study to determine the antimicrobial effectiveness of using copper, brass, and bronze on touch surfaces to reduce hospital‐acquired infections, with promising results.

The idea of copper fighting harmful microbes is nothing new. The Copper Development Association uncovered a few millennia of testing, sampling, and use of the element:

  • 2000 BC – Copper was used to sterilize drinking water and wounds.
  • 400 BC – Copper was found effective in treating leg ulcers related to varicose veins.
  • Roughly the 14th century – The Aztecs used copper oxide and malachite for skin conditions.
  • 1850 AD – Copper workers were found to be immune during the cholera epidemic.
  • 1983 AD – A U.S. hospital study found a low E. coli count on doorknobs made of brass (which contains a certain amount of copper).
  • 2005 AD – A study conducted in Punjab, India, discovered that E. coli was eliminated within 24 hours in water‐filled brass containers.

If the hypothesis is correct, copper has the ability to kill bacteria, and the results could revolutionize how health care and other public facilities manage the potential for infectious diseases.

Copper is a reliable building material.

Copper pipe lasts longer than plastic pipe, is durable, and connects well to valves. For years it was the gold standard in water pipes, and the only drawback, health‐wise, was the lead‐based solder used in joints. Now that lead solder has been banned, that is no longer an issue (although it is recommended that owners of older homes have their water tested for any lead residue).

Copper comes in three grades for water pipe, and the lettering on it is color‐coded:

  • M – thin wall pipe (used mainly in homes); red lettering
  • L – thicker wall pipe (used mainly outside for water services); blue lettering
  • K – the thickest wall pipe (used mainly between water mains and the water meter); green lettering

DWV Copper is used for drainage pipe and has yellow lettering.

The Bad

Copper may cause deficiency and toxicity issues.

Both too much and too little of copper in your diet can affect brain functions. Deficiencies are rare, but they have been linked to conditions such as Menkes disease. Studies have shown that a copper imbalance, including a toxic level of copper in the body, is linked to Alzheimer's disease.

Copper can be toxic in high volumes, but that's a rare occurrence in drinking water. According to the Centers for Disease Control and Prevention (CDC), "high levels of copper may get into the environment through mining, farming, manufacturing operations, and municipal or industrial wastewater releases into rivers and lakes."

Illness from drinking water is less likely to be copper‐related and more likely to come from too much flux or pipe compound that was used to join the pipes and fittings. If that's the case, the solution is to flush the water out to remove the excess.

Copper pipe can corrode.

The CDC notes that high levels of copper can get into drinking water through either well water that has been contaminated or through corrosion of copper pipes. The only way copper pipes will corrode is through acidic interaction, such as low pH levels in the water or if it's buried in certain soils with high acidity such as cinders.

If you live in an area with lower pH levels, you must have the water content tested and monitored. The CDC recommends that copper pipe not be used if the water has a pH of 6.5 or less. (This level could be higher or lower in different areas of the country. Check with your local permitting office to be sure.) Acid neutralizers can also be used to raise the pH to acceptable levels.

Corrosion can also be caused by electrolysis (stray electrical currents) formed by improper grounding or connecting dissimilar metals, such as galvanized to copper. These electric currents could wear the material or could cause pinholes. However, it's more likely that the pipe would leak long before copper would leach into the water through corrosion.

It's worth noting that "hard" water – that which contains large concentrations of minerals such as calcium or magnesium – does not corrode copper pipes.

If testing shows larger than normal amounts of copper in your water, you should flush the water out – at each faucet – for at least 15 seconds before drinking or using the water. For conservation purposes, the flushed‐out water can be used for watering plants, washing dishes or clothing, or cleaning.

Heating or boiling water will not remove copper from water, nor will chlorine bleach. To remove the copper completely, you might consider water treatment methods such as reverse osmosis, ultra‐filtration, distillation, or ion exchange. The downside is that these methods are used at one faucet at a time rather than in a whole‐house system.

Using copper pipe is labor intensive.

Installing copper pipes in a home or building takes longer to cut, clean, burr, and connect. This raises the cost of the job.

In addition, the velocity of water in copper pipes should not exceed the following levels:

  • Cold water systems with a flow duration of over 15 minutes = 6 feet per second (fps) or less
  • Hot water systems up to 140 degrees, with a flow duration of over 15 minutes = 5fps or less
  • Hot and cold water systems with a flow duration of under 15 minutes = 8fps or less
  • Smallest tubing sizes = 1.5 to 3fps
  • Hot recirculating systems = 1.5fps or less

Giving consideration to such standards will cause more work for estimating and pricing jobs. However, correctly sized systems should be a priority when estimating a job.

Pro Tip: We highly recommend that you ream all copper pipes after you cut them to reduce turbulence and velocity problems. It may also be helpful to "oversize" your copper to help slow down the speed of the water running through the pipes. The system will be much quieter and the potential for water hammer will be eliminated or greatly diminished.

The Ugly

The ugliest detail of copper is the bottom line: it's not a cheap material to use, and its cost is on the rise. When it's referred to as the "gold standard" of piping material, that's almost a literal interpretation.

The steep price of copper is no secret to most contractors, especially those in the plumbing industry. A side‐by‐side comparison of installing PEX, CPVC, or other plastic water line versus installing copper lines would show copper at twice or three times the cost of plastic water line.

The value of copper is notorious in the building trades, with the occasional copper gutters stolen and sold to scrap yards for high dollars. In fact, because its high value makes it a thief‐magnet, you could find yourself replacing copper on a job site several times. In some areas, you must have a certificate from the local police department to be able to sell copper at a salvage yard.

In the end, the use of copper might come down to personal preference and the owner's budget. When determining whether to use copper piping or when advising a customer about an installation, consider all angles of the material. There's more to copper than meets the eye.


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Frequently Asked Questions

Q. "Will using a thicker walled copper pipe help fix my corrosion problems?"
A. Most city water has to meet the EPA's list of maximum containment levels for contaminants - pH included. Type M copper is capable of lasting a lifetime under these guidelines. If there is something from well water or another source causing the piping to corrode, the problem should be fixed rather than postponing the inevitable with a thicker walled pipe. We do not believe that installing thicker pipe (i.e. going from type M to type L or to type K) is the solution to problems associated with using copper. We believe that the cause of corrosion should be solved rather than allowing the copper to leach into the drinking water. If the cause cannot be fixed or determined, then possibly using an alternative-piping product should be considered.

Q. "I have pinholes on only the cold side of my copper piping - what is the problem?"
A. Pinholes can be caused by localized corrosion cells established next to the pipe wall due to excessive oxygen. If you have more leaks in the cold side compared to the hot side then possibly it is dissolved oxygen in your water. When the water is heated, the oxygen is released and vented through the pressure release on the tank. When this happens, less corrosion. The solution is to release the excess oxygen prior to entering all the plumbing.


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