Distillation is not a common water treatment system used for private wells or private water systems (it’s expensive). In water distillation, it is typically advisable to provide some pretreatment that may include particle filtration, water softening, and possibly post-filtration using an activated-carbon block filter. Distillation requires heating the water to the point of creating a water vapor, i.e., boiling, and then cooling the vapor to produce a 99.9%+ pure water. Vacuum distillation can be used to cause the water to initially evaporate. Distillation systems are not commonly used for private water systems, but can be found in industrial applications, research laboratories, and some waste-treatment applications. Treatment applications include some metals, salts, sulfate, and some organics (not volatile organic compounds). After treatment, it is likely the water will have a “flat” taste (the water is too pure). Because the units that are available for private water systems typically produce relatively small volumes of treated water, i.e., as low as 0.5 gallons per hour, these units are typically installed st point-of-use treatment systems and not whole-house treatment systems.
Because PFASs, Per- and Polyfluoroalkyl Substances (the "forever chemicals") will break down (decompose) readily at high temperatures, it is likely that distillation may be an effective treatment approach for these chemicals, but this has not yet been confirmed.
Distillation systems heat water to the boiling point and then collect the water vapor as it condenses, leaving behind contaminants such as heavy metals. Some contaminants that convert readily into gases, such as volatile organic chemicals, can carry over with the water vapor. Therefore, low levels of PFASs may be treatable, but it is not likely that the system would adequately remove volatile organic compounds.
NSF International provides a standard for commercial distillation units. The standard is known as NSF/ANSI 62-2017. " This standard establishes minimum materials, design and construction, and performance requirements for point-of-use and point-of-entry drinking water distillation systems and the components used in these systems. " With respect to PFOA / PFOS, the NSF, until recently, had two separate standards that applied as follows:
From the NSF Website (5/19/2020) "to comply with the standards, a device must reduce PFOA and PFOS concentrations in water to below the 70 parts per trillion (ppt) health advisory level set by the U.S. Environmental Protection Agency (EPA). Devices must also comply with material and physical requirements of NSF/ANSI 53: Drinking Water Treatment Units – Health Effects or NSF/ANSI 58: Reverse Osmosis Drinking Water Treatment Systems. Certified products must be retested periodically and manufacturing facilities must be inspected every year, which ensures products continue to meet all requirements. Previously, the PFOA and PFOS performance requirements were outlined in a protocol named NSF P473: Drinking Water Treatment Units – PFOS & PFOA". NSF International is an American product testing, inspection, and certification organization based in Ann Arbor, Michigan.
Note: It is probably not a good idea to drink a lot of distilled water; there is such a thing as water that is too pure (although distilled water is preferred for irons). Water treatment plants that use distillation will add minerals to the distilled water to improve the taste and health of the water.
We recommend that, prior to installing a CounterTop POU (Point-of-Use) Unit, you Get Informed by gathering as much information as possible and Get Tested by conducting multiple levels of testing depending on your needs: Level 1 Observational Testing using our Self Test Web App, Level 2 Do-It-Yourself Testing, Level 3 Informational Lab Testing and, if needed, Level 4 Certified Testing conducted by a water professional.
If you have any questions please Contact the KnowYourH2O team.
Prior to implementing a treatment solution, we recommend the following tests:
The following are recommended Distillation Systems: