Are copper pipes safe for drinking water?

Yes. The 2024 IPC lists copper and copper-alloy tubing, Types K, WK, L, WL, M and WM, among the materials approved for water service and distribution piping. Chapter 6 also sets how the joints are made. For soldered joints on copper pipe, Section 605.12 says the cut ends must be reamed to the full inside diameter, the joint surfaces cleaned and flux applied, and that the joining of water supply piping shall be made with lead-free solder and fluxes. The code defines "lead free" here as a chemical composition equal to or less than 0.2 percent lead. It adds that solder and flux for drinking water piping must conform to NSF 61. The same lead-free solder rule appears for copper tubing in Section 605.13.

So a properly built copper system today is made of an approved pipe, joined with lead-free solder. That is the baseline the rest of this page compares against.

The EPA regulates copper in public water systems with an action level of 1.3 milligrams per liter, and the health goal for copper is also 1.3 mg/L. An action level is different from a maximum contaminant level. It is a trigger: if enough tested homes in a water system exceed it, the water system has to act, for example by adjusting its treatment so the water is less corrosive. The EPA's table lists the source of copper in drinking water as corrosion of household plumbing systems and erosion of natural deposits.

The health effects the EPA names depend on the length of exposure:

• Short-term exposure above the action level: gastrointestinal distress.
• Long-term exposure above the action level: liver or kidney damage.
• Wilson's disease: the EPA says people with this condition should consult their own doctor if the copper in their water exceeds the action level.

The federal toxicology profile for copper adds context. It says copper is required for many physiological functions, and that its recommended dietary allowance for adults is 900 micrograms a day with a tolerable upper intake of 10 milligrams a day, though those values differ for children and for pregnant and lactating women. It also says excess copper can come from sources such as copper contamination in drinking water. Studies it reviews found gastrointestinal upset, mostly nausea, vomiting and stomach pain, after people drank water with elevated copper, and controlled studies at lower levels found no signs of liver damage. The CDC lists the same symptoms for copper in water: nausea and vomiting, diarrhea and stomach pain.

### How common is high copper in tap water?

Less common than it used to be. The toxicology profile reports that since the EPA's Lead and Copper Rule took effect in 1991, action level exceedances have decreased by over 90 percent. It also reports that copper was above the action level in about 0.06 percent of the domestic wells the U.S. Geological Survey sampled from 1991 to 2004. The profile notes that copper-contaminated water may have a light blue or blue-green color with a metallic, bitter taste. If you see blue-green staining or taste a metallic edge, have the water tested.

### When does copper pipe put extra copper in the water?

Copper gets into water when the water dissolves it from the pipe. The EPA's lead page describes the same corrosion process for lead, and the factors are the same ones that apply to any metal in a plumbing system. It lists:

1. 1The chemistry of the water, meaning acidity, alkalinity and the types and amounts of minerals in it.
2. 2The amount of metal the water contacts.
3. 3The temperature of the water.
4. 4The amount of wear in the pipes.
5. 5How long the water stays in the pipes.
6. 6Whether protective scales or coatings have formed inside the plumbing.

The EPA says lead enters water especially where it has high acidity or low mineral content that corrodes pipes and fixtures. Water sitting in a pipe for hours has more time to pick up metal, which is why the first draw of the morning is the one to think about. The CDC gives a specific temperature point for copper: hot water dissolves copper more easily than cold water. Its advice is to avoid cooking with or drinking water from hot water taps.

Pipe that is corroding through the wall is a separate matter. If you already have leaks in copper lines, pinhole leaks in copper pipes explains what causes them, and what to do when a copper line keeps springing new pinholes covers when repair stops making sense.

This is the part most likely to matter for an older house. Copper pipe itself does not contain lead. Lead comes from what is joined to it.

The EPA says the most common sources of lead in drinking water are lead pipes, faucets and fixtures, and that lead pipes are more likely to be found in older cities and in homes built before 1986. Among homes without a lead service line, it says the most common problem is brass or chrome-plated brass faucets and plumbing with lead solder. That fits the history the EPA lays out:

• 1986. Congress amended the Safe Drinking Water Act to prohibit using pipe, solder or flux that was not "lead free" in public water systems or in plumbing providing water for human consumption. At the time, lead free meant solder and flux with no more than 0.2 percent lead, and pipe with no more than 8 percent.
• 2011. The Reduction of Lead in Drinking Water Act lowered the maximum lead content of the wetted surfaces of pipes, fittings and fixtures from 8 percent to a weighted average of 0.25 percent.

The 2024 IPC reflects both numbers. Section 605.2 says pipe and fittings, including valves and faucets, in the water supply system must have not more than 8 percent lead content, and Section 605.2.1 says the ones used for drinking or cooking water must comply with NSF 372 and have a weighted average lead content of 0.25 percent or less. If your copper plumbing was soldered before the mid-1980s, or the house has older brass fittings, lead is worth a test. Our page on how to test your home water for lead covers how to do it.

The CDC gives two habits for copper that also help with lead:

1. 1Flush unused faucets. If a faucet has not been used for 6 or more hours, run the water for at least 15 seconds before drinking or using it. The EPA's lead page gives the same advice in a broader form, saying the more time water has been sitting in pipes, the more lead it may contain, and suggests running the tap, taking a shower or running a load of laundry before drinking.
2. 2Use cold water for drinking and cooking. The CDC says hot water dissolves copper more easily. The EPA says to use only cold water for drinking, cooking and making baby formula, and notes that boiling does not remove lead from water.

If you want to treat the water rather than change habits, the CDC lists reverse osmosis, ultrafiltration, distillation and ion exchange as ways to remove copper, and says to look for water treatment systems certified to remove copper. The EPA says that if you use a filter for lead, it should be certified to remove lead and replaced on schedule, and that hot water should not be run through it. A filter helps at one tap. It does not change the pipe or the water chemistry behind it.

Call a plumber when you have a reason to believe the plumbing is the source, not the water main or a well. Good reasons include:

• Blue-green stains on fixtures or a metallic taste that shows up mostly at hot taps.
• A house built before 1986 with original soldered copper and no history of a lead test.
• New leaks in a copper line, or a run of pinholes.
• A remodel that will open walls, when swapping old brass fittings or shutoff valves costs the least.

A plumber can identify the pipe and fitting materials, find old solder joints and brass valves, and tell you whether a repair or a replacement is the right fix. If the answer is a replacement, whole house repipe options like PEX and copper walks through the choices without quoting prices, and signs of old, failing pipes helps you decide whether it is time.

HQ Plumbing and Air is licensed and insured, takes emergency calls 24/7, and gives free estimates with an upfront price before work starts. See our plumbing services.