What You Need to Know About Parasites in Drinking Water

According to the CDC, about 7.2 million Americans get sick every year from diseases spread through water. Two of the most common waterborne illnesses are caused by the parasites Cryptosporidium and Giardia intestinalis (also called Giardia lamblia or Giardia duodenalis).

Cryptosporidium and Giardia are microscopic parasites that can be found in water sources contaminated with human or animal poop. When the parasites get into your body, they live and reproduce in your intestines and are passed through your poop. Cryptosporidium (sometimes called “crypto”) and Giardia both cause diarrheal disease.

How could I come in contact with parasites?

Both Cryptosporidium and Giardia are common in natural surface waters (like rivers and lakes) and can survive for a long time in the environment. These parasites may be found in water, food, soil or surfaces that have been contaminated with the poop of infected humans or animals.

You may come in contact with Cryptosporidium or Giardia by:

  • Swallowing water while swimming or playing in lakes, streams, rivers, springs, ponds, swimming pools, hot tubs, or splash pads contaminated with Giardia or Cryptosporidium.
  • Eating food or drinking water or other liquids contaminated with Giardia or Cryptosporidium.
  • Touching your mouth after touching contaminated surfaces or objects, such as diapers or bathroom handles.
How can I stay away from parasites?
  • Do not drink or swim in water that might be contaminated. 
  • Try to keep water out of your mouth while swimming.
  • Wash your hands after swimming and before eating.
  • Regularly check your drinking water system to make sure it is sealed. 
  • Thoroughly wash all fruits and vegetables with clean water before eating.
  • Minimize contact with all human and animal poop, and wash your hands immediately after you do.
  • Do not touch your face or mouth after touching animals, and wash your hands as soon as possible after.
What do I do if I came in contact with parasites?

If you think you are having symptoms caused by parasites, first talk with your health care provider. Then follow these steps to make sure your drinking water system is safe.

Use a safe water source

If you are diagnosed with a parasite infection, switch to a known safe water source by:

Find out how parasites might be getting into your water supply

Dug wells, springs, and surface water sources are more susceptible to contamination than properly sealed drilled wells.

  • Test your water for total coliform and E.coli bacteria
    • If your results show bacteria were "detected" then surface water has somehow leaked into your water system, which means parasites like Cryptosporidium and Giardia could also get into your water supply.
  • Check for ways parasites could be getting into your water. 
  • Assume your drinking water source is contaminated if it has been exposed to animals or surface water runoff.
Testing: How do I know if parasites are in my water?

The Health Department Laboratory does not offer parasite testing in water, but testing may be available through other certified drinking water labs. Please note that specialized Cryptosporidium and Giardia tests are costly, require large water samples, and may not give reliable results. 

The Health Department recommends testing your water for bacteria and other common contaminants regularly. These results may indicate if your water system is susceptible to surface contamination. To order a Vermont Homeowner Testing Package or individual drinking water test kits, call the Health Department Laboratory at 802-338-4724. Learn more about testing your drinking water.

Treatment options: How do I make sure my water is safe to drink?

If you suspect your drinking water is contaminated with Cryptosporidium or Giardia, do not drink your water or use it for cooking, washing fruits and vegetables, brushing teeth, washing dishes, and making ice cubes, baby formula and concentrated juices. You can either:

  • Find a known safe source of water (such as the town library, town hall, fire department, school, church or town office), or 
  • Boil water for at least one minute before using it.

Unlike most bacteria, both Cryptosporidium and Giardia are resistant to chlorine disinfection. Chlorine alone is likely not enough to make sure the water is safe to drink. However, flushing and disinfecting your water supply can help resolve bacteria contamination after repairs have been made to the system.

Permanent treatment options for parasites include:

  • A filtration system that meets NSF/ANSI Standard 53 and is 1 micron (absolute), and is approved for cyst removal. 1-micron filters can clog quickly if sediment is in your water and may require additional pre-filtration to let the filter last longer.
  • An ultraviolet (UV) light treatment system that meets NSF Standard 55, along with any necessary pre-treatment to ensure effectiveness.
  • A reverse osmosis system with an NSF/ANSI Standard 58 certification.

Note: It is important to properly maintain any treatment system and change any filters by following the manufacturer’s instructions. Learn more about drinking water treatment.

Financial assistance: Is there funding available to help me pay for my water system or treatment?

Vermont Wastewater and Potable Water Revolving Loan Fund

This program, also known as the On-Site Loan Program, is available to certain Vermont residents for the repair or replacement of failed water supply and on-site wastewater systems. The On-Site Loan Program is funded and administered by the Agency of Natural Resources, Department of Environmental Conservation with loan underwriting and servicing provided by the Opportunities Credit Union in Winooski. Your drinking water supply has to be a failed system and you must be living in the residence on a year-round basis to be eligible. The family income cannot exceed 200% of the state median household income. For more information about eligibility and how to apply, call the On-Site Loan Program at 802-461-6051.

The NeighborWorks Alliance of Vermont

The NeighborWorks Alliance is made up of five local organizations offering full affordable housing services for income-eligible individuals. You may qualify for help from this program if you need money to install a water treatment system, drill a well, or repair or replace your septic system. For more information on eligibility, contact the NeighborWorks Group in your region.

Single Family Housing Repair Loans and Grants

This program offers loans and grants to existing homeowners for well construction, repair and sealing. It's administered by the Rural Development office of the U.S. Department of Agriculture. The program is for low-income families who live in a rural area or a community with a population of 25,000 or less. The family income cannot exceed 50% of the median county income. Individuals who are 62 years of age or older may qualify for a grant or a combination of a loan and a grant. Younger applicants are eligible only for loans.

Burlington, South Burlington, Essex Junction, Winooski and parts of Colchester are ineligible for the program. Even if your property is in an eligible area, your eligibility is still subject to income limits. For more information or to find out if your property is in an eligible area, call the USDA Rural Development Office at 802-828-6022.

Low-interest Loans for Individual Household Wells and Septic Systems

The Southeast Rural Community Assistance Project (SECAP) has partnered with RCAP Solutions (North Eastern Rural Community Assistance Partnership) to provide low-interest loans to construct, refurbish or replace individual water well systems and septic systems for eligible homeowners. Here are the requirements:

• Your residence must be in an eligible rural area, town, or community (defined as geographic area with 50,000 residents or less) in the RCAP Solutions service area of: Maine, New Hampshire, Vermont, Massachusetts, Connecticut, Pennsylvania, Rhode Island, New York, New Jersey, Puerto Rico and the U.S. Virgin Islands. 

• You must own (or provide recorded Lifetime Rights) and occupy the home being improved. 

• Your household limit is under the state median income limit.

• New home construction and community water systems are not eligible. 

Learn more about the loan program and fill out the form.

Please contact SERCAP staff for further information by phone at 540-345-1184 ext. 159 or email [email protected]

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