Why filtered water matters for dogs (not just humans)
Chlorine, sediment, and trail water all affect your dog's gut. Here's what a charcoal filter actually does.
Tap water is safe for dogs in most places, but it isn't neutral. Chlorine and chloramine — added to municipal supplies to kill bacteria — change the taste and can irritate sensitive stomachs over time.
Activated charcoal works by adsorption: porous carbon traps chlorine, VOCs, and odor molecules as water flows through. It doesn't soften water or remove minerals, which is exactly what you want for a dog.
On trails, the bigger concern is sediment and algae. A filter cap won't replace a wilderness purifier for backcountry sources, but it dramatically improves the taste and clarity of tap water topped up at a trailhead.
Swap the filter every 30 days. After that, the carbon saturates and stops working — it won't make water unsafe, just stops doing its job.