My wife and I spend our winters in Southern Oaxaca State. We have noticed some of these things as well. This may help with the water. You can order this water filter that will never wear out. Is one million gallons of drinking water enough? And yes they work. I found out that some people that volunteer to build wells in countries all over the world, use these. A believe they have membranes that are for kidney machines. If and when they clog up, an included syringe is used to back flush them. We bought the personal size ones for our go-bags (bug-out/disaster kits). See what you think.

From Amazon.

USA $32.60
http://www.amazon.com/Sawyer-Products-SP131-PointOne-Squeeze/dp/B005EHPVQW/ref=sr_1_2?ie=UTF8&qid=1427596022&sr=8-2&keywords=sawyer+water+filter

CDN$ 53.62 & FREE Shipping
http://www.amazon.ca/Sawyer-SP131-PointOne-Squeeze-Filter/dp/B005EHPVQW/ref=sr_1_3?ie=UTF8&qid=1427596179&sr=8-3&keywords=sawyer+water+filter