Saving water is important; however, when it comes to total home health, we also need to consider more than water quantity in green.

A point-of-use reverse osmosis (RO) system is designed to filter water at a specific location, like under your kitchen sink, using pressure to push water through a semi-permeable membrane. This process removes various harmful contaminants such as lead, PFAS, bacteria, and viruses. While these systems are great for improving water quality, they do waste a significant amount of water—often five gallons or more for every gallon treated. However, models labeled with WaterSense are more efficient, producing just 2.3 gallons of waste per gallon of treated water.

Though the water from public suppliers in the US is generally safe, some people may want extra treatment, especially for well water. WaterSense doesn’t endorse RO systems for every situation, as other methods, like filtration, might be enough and waste less water. For those considering a new RO system, WaterSense-labeled models can save over 3,100 gallons per year, leading to substantial water savings nationwide.

Performance-wise, WaterSense systems are certified to meet specific criteria, ensuring they effectively reduce contaminants and maintain the membrane’s lifespan. The EPA has established specifications for these systems, which will be discussed at an upcoming virtual public meeting on Dec 17th: register here.

While most of the residential green building programs disregard RO and do not award for it or consider it, the GreenHome Institute GreenStar Homes Certification requires water filtration at the Gold level of our certification or for the Healthier Home badge. Go here to learn about what is required and get educated on why we can’t just think about air quality but also must think about water quality for total home health. The GreenStar program’s Home Water Score calculator was recently updated to be more accurate for projected water usage. What’s your Home Water Score for your home or latest project?