A whole house RO system is rated by gallons per day (GPD). A family of four needs about 50 to 75 GPD. That’s enough for drinking, cooking, showering, and filling a kiddie pool (though please don’t).
Go too small, and your water pressure drops faster than your phone battery at 5 PM. You’ll be waiting forever for a shower. Go too big, and you’re burning cash on a system that feels like overkill. Like buying a Ferrari for grocery runs.
The Tank Tango
Most systems come with a storage tank—usually 4 to 20 gallons. It sits under your sink or in the basement. It’s bulky. It’s weird. Your friends will ask, “Is that a giant water bomb?” Answer: Yes. A delicious water bomb.
No tank systems exist too. They’re smaller, quieter, and cost 10% to 20% more. But they save space. Perfect for tiny homes or people who hate clutter. Or people who just want to brag about their no-tank RO.
