No, Brita is activated charcoal; it does not have an affinity for charged species such as calcium and magnesium ions. However, if you filter hard water with a Brita, the filtered water will be softer than the unfiltered water, as the Brita removes SOME of the calcium and magnesium in the water. However, it does not eliminate all calcium and magnesium.
Some people use Brita water to keep Betta fish, which works quite well.
It eliminates some pesticides and VOCs. However, because it only has a limited number of ion exchangers, it may remove some of them.
However, ion exchangers have a finite capacity that begins to degrade as soon as some ions are trapped. If you truly have a hard water problem, invest in a water softener or reverse osmosis system.
ALSO SEE: Do Water Filters Filter Out Microplastics?
MY Personal Experience
Brita softens the water slightly, but not significantly. Perhaps 20%.
I own both a Brita and a ZeroWater pitcher. Additionally, I have a TDS meter.
I mix approximately 85% ZeroWater and 15% Brita to achieve my goal of 50PPM water. I’m aware that some will argue that this is too soft to make good coffee.
I’m pleased with my shots and relieved that I won’t have to deal with descaling a HX for the foreseeable future.