Skip to content
My WebMD Sign In, Sign Up

Water Purification to Prevent Giardia

Font Size

Topic Overview

The cold, clear water found in mountain streams and lakes may look appealing but often contains Giardia lamblia, the parasite that causes giardiasis. On short hikes, you may be able to carry from home enough water to drink. But when you are camping and backpacking, you often need to use other water sources. Water from pumps in campgrounds is usually safe, but if a sign tells you that the water is not safe or if you have any doubts, treat the water before you use it.

To avoid infection with Giardia lamblia and other parasites, use one of these purification methods:

Recommended Related to

Rubella

Important It is possible that the main title of the report Rubella is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.

Read the Rubella article > >

  • Boil the water before using it for drinking, cooking, washing hands or dishes, or brushing your teeth. Bring the water to a rolling boil for 1 minute. If you are at an elevation of 6,562 ft (2,000 m) or higher, boil the water for 3 minutes. Even small amounts of water can contain parasites.
  • Add a chemical disinfectant to the water. Depending on the water temperature and how much sediment is present, you may need to let the water settle for several hours before you use it. You can find products to disinfect water in drugstores or camping supply stores. If the water is very cold or cloudy, increase the settling time before using it. Examples of chemical disinfectants are:
    • 5 tablets of halazone for 1 qt (1 L) of water. Treat for 30 minutes before using the water.
    • 1 Tbsp (15 mL) of crystalline iodine for 1 qt (1 L) of water. Treat for 30 minutes before using the water.
    • 0.1 tsp (0.5 mL) (about 5 drops from an eyedropper) of 2% tincture of iodine for 1 qt (1 L) of water. Treat for 70 minutes to 8 hours before using the water.
    • 2 to 4 drops (from an eyedropper) of household chlorine bleach for 1 qt (1 L) of water. Treat for 30 minutes before using the water. Iodine is considered to work better than chlorine against giardia.
  • Filter the water using a commercial filter specially designed for treating water. These filters range in price from $40 to $200 or more. The price generally depends on the quality of the filter and how fast it pumps water. Look for a filter that has these features, regardless of price:
    • Filter has an absolute pore size of 1 micrometer or less (will remove Giardia and some other parasites).
    • Labeling specifically states that it protects against Giardia.
  • Treat the water with a portable ultraviolet light that is designed to purify water. These devices can affect bacteria, viruses, and parasites so they can no longer reproduce. But these devices work best on water that has already been partly purified by another method.
1

WebMD Medical Reference from Healthwise

Last Updated: September 09, 2011
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
Next Article:

Water Purification to Prevent Giardia Topics

Hot Topics

WebMD Video: Now Playing

Click here to wach video: Dirty Truth About Hand Washing

Which sex is the worst about washing up? Why is it so important? We’ve got the dirty truth on how and when to wash your hands.

Click here to watch video: Dirty Truth About Hand Washing

Popular Slideshows & Tools on WebMD

hands on abdomen
Can you catch one?
Woman sitting in front of UV lights
Is yours working?
woman using breath spray
What's causing yours?
womans hand on abdomen
Are you ready for baby?
MS Overview
Recognizing symptoms.
bowl of yogurt with heart shape
Eat for a healthy heart.
woman doing pushups
To help you get fit.
Colored x-ray of tooth decay
Know what to look for.
Woman sitting with child
Do you know the symptoms?
mosquito
Stings, bites, burns, and more.
Allentown, PA
Are you living in one?
Thyroid exam
See how much you know.

Women's Health Newsletter

Find out what women really need.