Check out this link (click here).HM Digital COM-100 Waterproof EC/TDS/TEMP Meter
As you said, "Water comes before firearms, medicines and even food."
Here is another link to the same product (click here).Hand Held TDS Conductivity Meter
The second link has the following review:
I own a commercial water testing laboratory. This is the best portable conductivity meter I've ever seen and it has a very reasonable price.
Hi, that's pretty cool, I didn't even know these water testers even existed.
I found this other one that seems to be another good alternaitve for testing water quality.HM Digital Pocket Size TDS Meter TDS-4 Water Quality Tester
I'm not sure if it detects all sorts of micro organisms but it must narrow down nicely the sort of purity of water you are dealing with or how effective a filter actually is.
Product Description:Thanks for the tip, I didn't know there was something like this out there.
A TDS tester that's ideal for all water purification applications, wastewater regulation, aquaculture, hydroponics, and colloidal silver. Perfect for both consumer or commercial use. Carry one in your pocket at all times! .. The smallest and lightest TDS meter on the market. .. Sleek design is perfect for personal or consumer use. ... Hold Function: saves measurements for convenient reading and recording. .. Auto-off function: the meter shuts off automatically after 10 minutes of non-use to conserve batteries. ... Measurement Range: 0-9990 ppm. From 0-999 ppm, the resolution is in increments of 1 ppm. From 1000 to 9990 ppm, the resolution is in increments of 10 ppm, indicated by a blinking 'x10' image. ... Factory Calibrated: our meters are calibrated with a 342 ppm NaCl solution. Meters can be recalibrated with a mini-screwdriver.