What removes heavy metals from tap water?

The EPA sets legal limits, called maximum contaminant levels, for several metals in public water. The ones people ask about most are arsenic, lead, copper, chromium, cadmium, mercury, barium and selenium.

• Arsenic: the limit is 0.010 milligrams per liter, which is 10 parts per billion.
• Lead: the goal is zero. The EPA regulates lead with a treatment technique and an action level of 15 parts per billion measured at customer taps.
• Copper: the action level is 1.3 milligrams per liter.
• Chromium (total): the limit is 0.1 milligrams per liter, or 100 parts per billion.
• Cadmium: 0.005 milligrams per liter.
• Mercury (inorganic): 0.002 milligrams per liter.
• Barium: 2 milligrams per liter.
• Selenium: 0.05 milligrams per liter.

Now look at what one big local utility reports. In its 2025 report, the City of Phoenix lists these detections in its water: arsenic from not detected to 8.5 parts per billion, chromium from not detected to 87 parts per billion, barium from 0.007 to 0.13 parts per million, and selenium from not detected to 2.2 parts per billion. Every one of those falls under the EPA limit, as the report shows in its table. The report adds that while the water meets the arsenic standard, it does contain low levels, and the EPA continues to research the health effects of low levels of arsenic.

Lead and copper work differently. Phoenix's tap sampling from residential taps found lead from not detected to 41.8 parts per billion, with 90 percent of taps at or under 3 parts per billion. Two of 56 sampled taps were above the 15 parts per billion action level, and none of the 56 were above the copper action level. The city's report explains why: lead in drinking water comes mainly from service lines and home plumbing, and the city cannot control the materials used inside your home. That is why the most common heavy metal question at a house is really about your own plumbing, not the water leaving the plant.

If arsenic is your concern, our page on arsenic in Arizona drinking water goes deeper. To find out whether lead is in your house water, start with how to test home water for lead.

NSF lists the standards that apply to home treatment. Here are the ones that matter for metals.

### Filters certified to NSF/ANSI 53

NSF/ANSI 53 covers filters certified to reduce a contaminant with a health effect. That includes carbon-based filters that trap contaminants in the pores or on the surface of the media. The important detail is that manufacturers pick which contaminants their product claims to reduce. NSF says NSF verifies that the filter will do what it says, and that you need to check the package for both the standard name and a claim for the specific contaminant, such as lead. A filter certified to NSF/ANSI 53 for lead is not automatically certified for arsenic.

The EPA gives the same instruction for lead. If you use a filter, use one certified to remove lead, read the directions on installing it and replacing the cartridge, and know that an expired cartridge can be less effective. The EPA also says not to run hot water through the filter.

### Reverse osmosis certified to NSF/ANSI 58

NSF describes reverse osmosis systems as using reverse pressure to force water through a semi-permeable membrane. Most also include one or more additional filters on either side of the membrane. NSF/ANSI 58 certified systems reduce contaminants regulated by Health Canada and the EPA. The CDC says reverse osmosis removes some chemicals, including lead, copper and chromium, and may reduce arsenic, fluoride, radium and nitrate, and it tells you to check the system's label for the specific chemicals it removes. As with the filters above, the certification lists specific claims, so check the ones that match your worry. Reverse osmosis is a point-of-use tool that treats water at one tap, most often under the kitchen sink. For upkeep, see our page on reverse osmosis filter replacement and maintenance, and for the trade-offs, whether reverse osmosis is worth it. If you wonder whether it removes healthy minerals too, our page on reverse osmosis and minerals covers that.

### Distillation

NSF lists distillation systems under NSF/ANSI 62. They heat water to boiling and collect the vapor as it condenses, which leaves contaminants such as heavy metals behind. NSF adds that some contaminants that convert readily into gases, such as volatile organic chemicals, can carry over with the water vapor. The CDC lists arsenic, barium, cadmium, chromium, lead and nitrate among the chemicals distillation removes, and says it does not remove some volatile organic compounds, solvents and certain pesticides. So distillation handles metals well but is not a cure-all.

Some common fixes do not work, and a few can backfire.

• Boiling. The EPA says plainly that boiling water does not remove lead from water.
• A water softener with no metal claim on its label. NSF/ANSI 44 covers softeners, which use a cation exchange resin to reduce hardness caused by calcium and magnesium. The CDC adds that some softeners may also remove iron, manganese, arsenic, chromium or other metals, and tells you to check the product's label for the specific chemicals it removes. If the label claims only hardness, do not count on it for metals. If you want a softener for scale, that is a separate decision, and our guide on signs you need water treatment helps sort out which problem you have.
• A basic pitcher or refrigerator filter with no metal claim. If the package says nothing about lead or arsenic, do not assume it treats them.
• Whole-house sediment or carbon filters. NSF describes whole-house filters as commonly aimed at chlorine, taste, odor and particulates. A certified point-of-use unit is the more common route for metals, unless a whole-house product carries the specific claim and certification you need.
• Ultraviolet treatment. NSF/ANSI 55 covers UV systems, which NSF describes as inactivating bacteria, viruses and cysts. That is microbial treatment, not metals treatment.

Test your water first, then match the product to the result. The EPA says you cannot see, taste or smell lead dissolved in water, and testing is the only sure way to know whether harmful amounts are present. Testing also tells you which metal to look for on the package, so you avoid paying for treatment that targets the wrong thing. The EPA suggests contacting your water supplier, which may also know whether your home's service line contains lead.

Then follow these steps.

1. 1Get the result in writing. Note the metal and the level, and compare it with the EPA limit above.
2. 2Pick a certified product that lists that metal. Look at the package, and the NSF listing, for the standard and the specific claim.
3. 3Install it on the cold water line. The EPA says use only cold water for drinking, cooking and making baby formula.
4. 4Replace the cartridge on time. A filter that has gone past its rated life is the most common way a certified product stops working. Our page on changing a whole-house filter explains how service cycles work.
5. 5Flush after the water sits. The EPA advises running the tap before drinking when water has been sitting in pipes, because the longer it sits, the more lead it may contain.
6. 6Consider fixing the source. If the test shows lead from your own plumbing, removing the leaded part is a better long-term answer than treating the water at one tap. A licensed plumber can look at the service line, fixtures and fittings, and we give an upfront price before any work starts, plus a free estimate.

Here are the short versions.

Does a pitcher filter remove lead? Only if that specific pitcher is certified for lead reduction under NSF/ANSI 53. Check the package for the claim.

Is Phoenix tap water safe from heavy metals? The city's 2025 report shows metals detected below their federal limits, and reports lead sampling at customer taps that included two of 56 sites over the action level. If you are pregnant, feeding a baby formula or concerned about your plumbing, test your own tap.

Can I remove arsenic with a filter? Only with a product that carries an arsenic claim. Look up the product in NSF's certified listings and read the claims, because each certification names specific contaminants.

Do I need to treat the whole house? Usually not. Most people who want metal removal treat the drinking and cooking tap, which is where the water gets consumed.