HERE IN ALASKA I USE A FILTER ALL THE TIME I HAVE HAD A "SWEET WATER" PUMP FOR PROBABLY 10 YEARS I REPLACED THE FILTER THIS YEAR. GIARDIA WILL HIT YOU IN 2-3 WEEKS IF NOT MORE SO YOU WILL BE HOME....MOST LIKELY BUT THE OTHER BACTERIA IS WHAT CAN CAUSE YOU TROUBLE WITHIN A FEW HRS. LAST THING YOU NEED IN A REMOTE AREA IS NON STOP HERSHEY SQUIRTS. [:'(][:@][]ALSO EVEN THOU GIARDIA IS DELAYED SOME FOLKS HAVE SPENT DAYS IN THE HOSPITAL AND THAT CAN BE EXPENSIVE AND CAN MEAN LOST TIME FROM WORK. I STRONGLY RECOMMEND THE PUMP. GET A TYPE OF PUMP THAT PUMPS IN BOTH DIRECTION OF THE PUMP STROKE.