I would filter all the water.
Beat you to it. The New Driftless Gold-Water Filtration System is close to completion and ready for use in the near future. Hooks up to every faucet for instant gold fitering pleasure. Please send a five....uh...ten....er.....twenty thousand dollar cashiers check to this P.O. box, and I promise to send you my gold filtration system. Very soon. I promise you’ll get it sometime in the near future. Which might take a while due to shipping and handling problems. Be patient if you don’t get your system within a year’s time. Trust me. Your filtration system will be in the mail.