Water filtration straws do work. They filter out most harmful germs from water.
Many top models, like LifeStraw and Sawyer, use tiny hollow fibers. Pores block bacteria and parasites. Tests show they remove 99.9999% of bacteria and 99.99% of protozoa.
Labs certify them under NSF or EPA standards. Field use in disasters and hikes backs this up. Groups like the Red Cross recommend them.
They miss viruses, chemicals, and salts. Flow slows when dirty; clean them often. Use only clear water. For murky sources, pre-filter first.
Pick certified brands. They save lives in bad water spots. But pair with safe habits.