Springs in volcanic areas cannot be relied upon. The water often does not filter thru sandstone or a pourous aquifer like in sedimentary rocks. The " springs" in this area can be little more than fissures that water from lakes and runnoff flows thru. No filtering involved. DO NOT DRINK ANY WATER FROM SUCH A SOURCE WITHOUT BOILING, FILTERING, OR CHEMICALLY TREATING. Outfitters are full of sh!t about water. Most of ' em had giardia at one time or another. I had one tell me he' d been drinking lake water near his camp for 20 years with no problem. Its like driving without a seat belt. It only takes once to make a BIG difference. Insist on boiling or filtering water for your personal use. An' if you don' t an' end up spendin' yer trip squirtin' in the bushes an' tendin' to a blood raw bung hole, don' t say I didn' t warn ya.