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Water Filters

Water Filters

Water Filters

If you are interested in learning more about water filtration options for your home, the information here can help you get started.

Point-of-entry (POE) systems, treatment that is installed near the location where the water service line enters a home, can be effective for reducing contaminants from the water entering the home. It will not reduce contaminants that are released from plumbing inside the home. It is not as reliable as point-of-use (POU) devices for lead reduction because there are multiple potential sources of lead in household plumbing, as described here. Lead can dissolve into water passing through household plumbing after it has been treated by a point-of-entry system.¹,²

It is important to select point-of-entry devices that are certified to reduce the contaminants you are concerned about. Certification standards and product markings are described here.

References:

Point-of-entry (POE) systems, treatment that is installed near the location where the water service line enters a home, can be effective for reducing contaminants from the water entering the home. It will not reduce contaminants that are released from plumbing inside the home. It is not as reliable as point-of-use (POU) devices for lead reduction because there are multiple potential sources of lead in household plumbing, as described here. Lead can dissolve into water passing through household plumbing after it has been treated by a point-of-entry system.¹,²

It is important to select point-of-entry devices that are certified to reduce the contaminants you are concerned about. Certification standards and product markings are described here.

References:

You may want to consider point-of-use (POU) treatment or filtration because of sources of lead in your plumbing, sample results for your home, information from your water supply, or from hearing about lead in the water in other communities. You should use filtered or treated water for drinking, cooking, or preparing formula if you have a lead service line, or if you have a pregnant woman or children under 6 years old in your home.

Always follow the manufacturer’s instructions when installing or using any water treatment system. You will need to replace the filter cartridge on a schedule as instructed by the manufacturer.

All tests for drinking water treatment devices are completed using cold water, so you should only use cold water in your treatment device at your home. Most faucet mount filters have a bypass that you can use for washing dishes with hot water. 

When a device has an indicator that tells you when to change a filter cartridge, the indicator device typically measures the time the treatment unit has been in use or measures the water flow through the device. In most cases, the indicator does not measure when the filter is no longer reducing contaminants from the water.

The Michigan Department of Health and Human Services (MDHHS) has made YouTube videos to explain how to install¹ and replace² Brita faucet mount filters.

References:

  • ¹ “Brita Faucet Filter Installation”. YouTube, uploaded by the Michigan Department for Health and Human Services, February 12, 2019, youtube.com/watch?v=fdGjZWAF6RU.
  • ² “How to Replace your Brita Water Filter.” YouTube, uploaded by the Michigan Department of Health and Human Services, November 4, 2015, youtube.com/watch?v=plsOvmH___0

It is important to select water treatment devices that are certified to reduce the contaminants you are concerned about.¹ The device package should clearly indicate that the treatment device meets at least one drinking water certification standard, and the package should list the contaminants that it is certified to reduce as in the example below. The USEPA has developed a tool to help consumers recognize the markings on certified filter packages.³

Certified filter mark
Certified filter mark. Click to enlarge.

NSF/ANSI 53, NSF/ANSI 58, and NSF/ANSI 42 are the drinking water treatment certification standards you are likely to see. If you are selecting a device to remove lead, the package needs to state that it meets NSF/ANSI 53 or 58 for the reduction of lead.

NSF International (formerly known as the National Sanitation Foundation) is an independent, not-for-profit organization that writes standards, and tests and certifies point of use treatment devices. NSF International uses a consensus-based process to develop national standards which means that regulators (including the U.S. Environmental Protection Agency (USEPA)), consumers, academia, and industry are involved in developing standards. NSF International drinking water certification programs are accredited by American National Standards Institute (ANSI).

NSF/ANSI Standard 53 for Drinking Water Treatment Units is the nationally recognized standard for evaluating and certifying drinking water treatment systems for the reduction of contaminants from drinking water. NSF/ANSI Standard 58 is the national recognized standard for Water Treatment Systems that use reverse osmosis technology. Water filters are tested and certified to NSF/ANSI 53 and 58 to ensure they reduce contaminants, including lead, per the requirements of the standards.

The NSF/ANSI standards define specific tests that treatment devices must pass to be certified as effective for reducing an individual contaminant. Filters can be certified to reduce multiple contaminants.

NSF/ANSI 42 is used to evaluate and certify filters that reduce aesthetic impurities such as chlorine and taste/odor. These can be point-of-use or point-of-entry treatment systems. Both NSF/ANSI 42 and 53 cover adsorption and filtration which is a process that occurs when liquid, gas, or dissolved/suspended matter adheres to the surface of, or in the pores of, an adsorbent media. In contrast, NSF/ANSI 58 uses reverse osmosis system that uses reverse pressure to force water through a semi-permeable membrane. Most reverse osmosis systems incorporate one or more additional filters on either side of the membrane.5

References:

It is important to select point-of-use (POU) and point-of-entry (POE) water treatment devices that are certified to reduce the contaminants you are concerned about. These devices are certified using the NSF/ANSI certification program as described here.

The NSF/ANSI standards define specific tests that treatment devices must pass to be certified as effective for reducing an individual contaminant. All drinking water treatment devices are tested using cold water. They are not tested for contaminant reduction at higher temperatures that you might use for showers or dishwashing.³ The lead reduction certification test uses water containing 150 parts per billion (ppb) of lead. The treatment device must reduce lead to 10 ppb or less¹ to be certified. A recent peer reviewed study found that certified filters reliably bring lead down to non-detect levels even when lead levels in the tap water are higher than the 150 ppb required in the certification test.4

References:

Water Filter Information

Change the filter cartridge when the indicator light flashes red or, for non-electric filters, when there is more red visible than green. Most filters are guaranteed to last for 100 gallons, which for an average family of four will be every 2-3 months. (Note: It is always a good idea to read the packaging to confirm that the filter you have has a 100 gallon lifetime. There are some products designed for longer performance.)

PUR and Brita can be contacted to provide the required adapter, or you can bring your faucet aerator and adapters from box to local hardware store and ask for help connecting the two.

For a battery powered filter housing, the batteries will die approximately every 2 years. The filter will still be functional, but there will be no indication of when the filter needs changed so it is advised to replace the system once the batteries die. The batteries are not replaceable.

Activated carbon filters are capable of filtering out copper but have only been tested and guaranteed to remove what it states on the box/instructions. PUR and Brita faucet filters differ on the exact types of contaminants they filter out, but both are certified to remove lead, chlorine, and most disinfection byproducts. To be sure, check the box/instructions/website for more information.

If there is a Boil Water Advisory, wait until the advisory has lifted and then change the filter.

No, it is never safe to run hot water through activated carbon filters. Other types of POU filters that do not use activated carbon, like those designed to remove legionella bacteria, are capable of filtering hot water.

Some shower filters have activated carbon and some use other technologies (such as membranes). We would strongly advise against using activated carbon filters in the shower because, although they remove lead and chlorine, they can also breed harmful bacteria.

More Water Filter Resources

Identifying Certified Drinking Water Filters

View/Download A Consumer Tool for Identifying Point of Use (POU) Drinking Water Filters Certified to Reduce Lead from the EPA (PDF).

Centers for Disease Control and Prevention

Choosing Home Water Filters & Other Water Treatment Systems

Visit Choosing Home Water Filters & Other Water Treatment Systems on the Centers for Disease Control and Prevention (CDC) website.

POU filter installation, use, and maintenance

Point-of-Use Filter Installation, Use, and Maintenance

Review Point-of-use (POU) filter installation, use, and maintenance (PDF) with this guide developed by Greater Flint Health Coalition, Community Foundation for Greater Flint, US EPA, Flint Neighborhoods United, Genesee Health System, Wayne State University, and the University of Michigan.