I keep a straw in my BOB as a backup to other more reliable methods. It is small enough to be a practical backup, where doubling up on a real filter system is less desirable.

BTW, it is really interesting how the people in Brisbane are resisting the notion of consuming purified recycled water. What do they think a Desal plant is? They are now below 20% in their reservoirs, and I shudder to think what the water quality of what's left is. Still, some of them would rather pay $10 a liter for water of inferior quality than to put recycle back in the dams. What a bunch of maroons.