How to Clean Lake Water

Knowing how to safely clean or purify water so it is safe for consumption is an essential survival skill. Water in lakes and other natural freshwater sources can contain harmful bacteria and disease-ridden spores. Simple steps can be taken to ensure these harmful substances are eradicated. Always carry water-purification tools with you when visiting the great outdoors.

Instructions

    • 1

      Check the water for chemicals and oil. Some toxins cannot be safely removed. If the water has a strong smell, is unusually colored, or there is evidence of dead wildlife on or beside the lake, find another water source.

    • 2

      Filter your collected water by pouring it through gauze or cheesecloth. If you are short of resources, a sock also works effectively. Repeat this process until all debris is removed and the water appears clearer.

    • 3

      Purify the filtered water by boiling it. Start a fire or use a gas burner to heat the water until it boils. Keep the water boiling for at least one full minute to ensure all harmful bacteria is killed. At higher altitudes you will need to boil the water longer. Allow to cool before consuming.

    • 4

      Purify the water with iodine pellets if boiling is not possible. If you are unable to start a fire, or do not have a heat-proof container to boil water, cleaning the water with iodine is an alternative purification method. Add an iodine pellet to the collected and filtered lake water. Let stand for a minimum of 10 minutes -- longer if the water is particularly cold.

    • 5

      Purify the water with household bleach if other methods are not viable. The Washington State Health Department says that water can be made safe for consumption by adding a few drops of five- to six-percent chlorine bleach. Add a minimum of three drops of bleach to a quart of lake water, and up to five drops if it is significantly cloudy. Mix thoroughly and let stand for at least 30 minutes. Only use this method as a last resort and drink in moderation -- over-consumption can have toxic effects.