Water from a properly installed and maintained household RO system can be used as drinking water. The important qualifiers are properly installed, maintained and appropriate for the source water.
What matters in practice?
- Use a system designed for the intended source water.
- Replace filters and membranes according to the manufacturer's schedule.
- Keep reservoirs, taps and contact surfaces clean.
- Check current product testing or certification where available.
- Follow the manufacturer's instructions if the system has been unused for an extended period.
For a specific health concern, contamination incident or unusual water source, use the advice of your local water supplier or an appropriately qualified professional rather than relying on a generic product article.
What about minerals?
RO can reduce dissolved minerals. Some systems add minerals afterwards. That is a product-design question and should not be confused with a blanket statement that all drinking water must be remineralised.