Giardia in Drinking Water
An alternative to boiling water is using a point-of-use filter. Not all home water filters remove Giardia. Filters that are designed to remove the parasite should have one of the following labels:
- Reverse osmosis
- Absolute pore size of 1 micron or smaller
- Tested and certified by NSF Standard 53 for cyst removal
- Tested and certified by NSF Standard 53 for cyst reduction.
Although Giardia is larger than 1 micron in size, filters with pore sizes of absolute 1 micron can filter out Giardia as well as Cryptosporidium.
If you are considering ways to disinfect your well, it is important to note that Giardia is moderately chlorine-resistant. Contact your local health department for recommended procedures. Remember to have your well water tested regularly after disinfection to make sure the problem does not happen again.