SFPUC's water meets all water quality standards. Note that during 1998 the SFPUC did not find any Cryptosporidium in its treated water that went to your tap. Some people have concerns that lead them to purchase a water filter or bottled water.

The information below is geared towards minimizing the occurance of cryptosporidiosis, a disease associated with the parasite Cryptosporidium that is found in most surface water supplies. If swallowed, Cryptosporidium may produce diarrhea, stomach cramps, upset stomach and fever. Some people are more vulnearable to Cryptosporidium than others and should seek advice from their health care providers about drinking water. Proper tap water filtering and bottled water are two possible methods of minimizing cryptosporidiosis. The following guide provides information to consumers so that they can make more informed choices.

Filtering tap water

Not all available home water filters remove Cryptosporidium. All filters that have the words "reverse osmosis" on the label protect against Cryptosporidium. Some other types also work, but not all filters that remove objects 1 micron or larger from water are the same. Look for the words "absolute 1 micron." Some "1 micron" and most "nominal 1 micron" filters will not work against Cryptosporidium. To find out if a particular filter removes Cryptosporidium, contact NSF International (3475 Plymouth Road, P.O. Box 130140, Ann Arbor, MI 48113-0140, 1-800-673-8010, fax: 1-313-769-0109), an independent testing group. Ask NSF for a list of "Standard 53 Cyst Filters." Check the model number on the filter you intend to buy to make sure it is exactly the same as the number on the NSF list. Look for the NSF trademark on filters, but be aware that NSF tests filters for many different purposes. Also look for the words "Standard 53" and the words "cyst reduction" or "cyst removal" for an NSF-tested filter that works against Cryptosporidium. Because NSF testing is expensive, many filters that may work against Cryptosporidium have not been tested. Reverse osmosis filters work against Cryptosporidium whether they have been tested by NSF or not. Many other filters not tested by NSF also work if they have an absolute pore size of 1 micron or smaller.  Additionally, you can check to see if a filter is certified by the California Department of Health Services by clicking on the the following link:
DHS Filter Certification

If you choose to buy a filter, look for this information on the label:

• Filters designed to remove Cryptosporidium
  (any of the four messages below on a package label indicate that the filter should be able to remove Cryptosporidium)
• Reverse osmosis (with or without NSF testing)
• Absolute pore size of 1 micron or smaller (with or without NSF testing)
• Tested and certified by NSF Standard 53 for cyst removal
• Tested and certified by NSF Standard 53 for cyst reduction

• Filters labeled only with these words may not be designed to remove Cryptosporidium
• Nominal pore size of 1 micron or smaller
• One micron filter
• Effective against Giardia
• Effective against parasites
• Carbon filter
• Water purifier
• EPA approved (Caution: EPA does not approve or test filters.)
• EPA registered (Caution: EPA does not register filters for Cryptosporidium removal.)
• Activated carbon
• Removes chlorine 
• Ultraviolet light 
• Pentiodide resins
• Water softener

Filters collect germs from water, so someone who is not HIV infected should change the filter cartridges; anyone changing cartridges should wear gloves and wash their hands afterwards. Filters may not remove Cryptosporidium as well as boiling does because even good brands of filters may sometimes have manufacturing flaws that allow small numbers of Cryptosporidium to get past the filter. Also, poor filter maintenance or failure to replace filter cartridges as recommended by the manufacturer can cause a filter to fail.

Bottled Water

If you drink bottled water, read the label and look for this information:

• Water labeled as follows has been processed by method effective against Cryptosporidium
• Reverse osmosis treated 
• Distilled
• Filtered through an absolute 1 micron or smaller filter
• "One micron absolute"
• Water labeled as follows may not have been processed by method effective against Cryptosporidium
• Filtered
• Micro-filtered
• Carbon-filtered
• Particle-filtered
• Multimedia-filtered
• Ozonated 
• Ozone-treated 
• Ultraviolet light-treated 
• Activated carbon-treated
• Carbon dioxide-treated
• Ion exchange-treated
• Deionized
• Purified
• Chlorinated

Bottled water labels reading "well water," "artesian well water," "spring water," or "mineral water" do not guarantee that the water does not contain Cryptosporidium. However, water that comes from protected well or protected spring water sources is less likely to contain Cryptosporidium than bottled water or tap water from less protected sources, such as rivers and lakes.  (See additional information from the International Bottled Water Association.)

Home distillers

You can remove Cryptosporidium and other germs from your water with a home distiller. If you use one you need to carefully store your water as recommended for storing purified water.

Other drinks

Soft drinks and other beverages may or may not contain Cryptosporidium. You need to know how they were prepared to know if they might contain Cryptosporidium.

If you consume prepared beverages, look for drinks from which Cryptosporidium has been removed: