I took one of the Base Camp filters to India to filter tap water. Should i be concerned about what might be growing in the filter now? thanks.

In India, water is often treated with lime... This precipitates out with boiling but not with filtering alone. For maximum safety in India and surrounding areas, depending on your location, filter your water first, followed by boiling and cooling to near room temp, followed by a filtration through a bandana to remove the precipitate. When an Indian tells me that the water isn't safe without the extra steps, I listen. Consequently, even though it was a pain, I followed through every single morning and night. No illnesses or stomach upsets ensued. I traveled throughout North and South India continuously for 5 months without illness or mishap.

Your concerns are justified but the main compartment is designed to contain suspect water. If you're still concerned, run a 32 to 1, water to bleach solution through it followed by a liter or two of clean water. From Ray. I just returned from doing a 16 day trek in Nepal. Our outfitter used 2 Base Camps. They love them, but also supplement them with Katadyn Micropur tablets if they suspect their water is below human feces and thus possibly contaminated with dangerous viruses. First they filter,then add one Micropur tablet per liter of water. Since the filter has taken out hard to kill protozoa (plus all bacteria), the remaining viruses are killed in 15 minutes. No chlorine or iodine taste either. I'll admit that chlorine bleach would also work, but I don't like carrying bleach, measuring bleach, pouring bleach, or tasting bleach. thanks, Ray