Wash well and don't forget the lid: how to clean your reusable water bottle
Reusable water bottles harbor bacteria introduced by hands and saliva and require regular, thorough cleaning with soap, diluted bleach or vinegar plus good hygiene.
Here's What Science Says About Double-Dipping And Germs - Tasting Table
Double dipping transfers saliva and bacteria into communal dip, greatly increasing contamination risk and potentially spreading thousands of bacteria between people.
You Should Never Leave Water In Your Nespresso Canister. Here's Why - Tasting Table
Refill Nespresso water daily because standing water loses chlorine, allows bacterial growth (including Legionella), alters taste via CO₂ absorption, and increases health risks.