Comment by mynameisnoone

Preaching to the choir here. ;] To be specific:

- RO for drinking water and icemaker for most people. Fancy: Bathroom faucet RO needs additional piping, pump (sometimes), and a larger tank.

- Whole house filters (3- to 5-stage carbon) provides a belts-and-suspenders check on tap water quality.

- Cation exchange (salt consuming) water softeners where applicable. Soft water feels good in the shower and improve laundry efficiency. A house's exterior and kitchen cold water ideally should be plumbed with filtered hard water, bypassing water softening for irrigation.