Water will be available for the weekend. Points are awarded when teams successfully purify water to make it drinkable, but those teams do not need to drink the water to prove that it's safe. We're focusing on confirming the ability to make clean drinking water.
Filtration
Remove as much sediment and foreign matter as possible.
Does not remove salt, dissolved chemicals, nor typically viruses.
Sterilization / Disinfection
Killing any living microorganisms within the water.
Does not remove debris. Works much better when water is clear.
Purification
Removal of minerals, chemicals, protozoa, viruses.
Distillation and a few filtration systems fit into this category.
Water Filtration and Some Purification
A water filter can be constructed using layers of different materials. The container can be an empty plastic bottle, an innertube, a plastic bag, or other materials. The layers could even be held by SEVERAL LAYERS of plastic or cloth. The charcoal should be as finely ground as possible. Purification comes from the charcoal, which can absorb some toxic chemicals.
Water Sterilization
According to the EPA, boiling clear water for 1 minute (or 3 minutes at altitudes over 5,000 ft / 1,000 m) is enough to kill all living things. Make sure the water was filtered and has attained a full, rolling boil to ensure it's at the right temperature.
Water Sterilization
Add 8 drops of bleach per gallon of clear water to kill anything living in the water. Double that for cloudy water. Make sure water is filtered before use.
CLOROX'S DISASTER PREPAREDNESS PAGE
Water Sterilization
Sunlight can kill anything living in the water. Full sun, clear water, and thinner bottles are needed because the killing properties of sunlight doesn't travel far into the water.
This method takes several hours and should be used as a last resort. Its effectiveness is questionable.
Reality Survival & Prepping
The Truth About Water Purification In A Wilderness Survival Situation
Great discussion of ways to purify water and why you should treat water that you find in the wilderness.
The King of Random
DIY: Make Swamp Water Drinkable
Notice how he differentiates between filtration and sterilization. One removes icky stuff and the other kills whatever's left.
desertsun02
DIY Solar Water Distiller! - Simple Solar Water Distilling - Easy DIY (for survival/SHTF)
Easy solar distilling of water using plastic bottles. For improved efficiency, put the upper bottles in shade.
All 4 Adventures
Emergency Water Source - Evaporating with a Solar Still: Survival Tip ► All 4 Adventure TV
Even though a small amount of water was captured over 12 hours, that amount of water could keep you alive. Once made, this solar still can keep working with minimal amounts of maintenance.
The Outsider
Survival- Turning Mud into Clean Drinking Water
Good way to distill water in a pinch. The summary at the end where it lists pros and cons is extremely informative.