Unregulated Contaminants Monitoring

Current Drinking Water Health Advisory Level

Cyanotoxins have not been detected in tap water, reservoirs, or the Tualatin River.
No action is needed.
Tap water continues to be safe to drink and use.

The Joint Water Commission (JWC) partners – that include the Cities of Hillsboro, Forest Grove, and Beaverton and the Tualatin Valley Water District – have finished their respective testing for cyanotoxins at various entry points to their respective water transmission systems.

Cyanotoxins are toxins produced by bacteria called cyanobacteria (also known as blue-green algae).

The testing was part of the fourth round of U.S. Environmental Protection Agency’s (U.S. EPA) Fourth Unregulated Contaminants Monitoring Rule (UCMR4). The UCMR4 rule required all public drinking water systems serving 10,000 or more customers (and some randomly selected smaller systems) to monitor for 30 unregulated contaminants between 2018 and 2020.

Testing Schedule
Partners took samples of treated drinking water where it enters their respective water transmission systems.

Testing occurred every other week for a series of eight consecutive tests. Testing periods included:

  • Hillsboro: June 2020 – September 2020
  • TVWD: June 2018 – September 2018
  • Beaverton: June 2018 – September 2018
  • Forest Grove: June 2019 – September 2019

During each of their respective sampling periods, none of the JWC partners detected any cyanotoxins.

What are Cyanotoxins?
Cyanotoxins are produced by cyanobacteria, also known as blue-green algae. Blue-green algae naturally occur in surface waters. Under certain conditions, such as in warm water containing an abundance of nutrients, they can rapidly form Harmful Algal Blooms (HABs).

Some of these blooms are capable of producing toxins known as cyanotoxins that can harm humans and animals.

Not all blue-green algae blooms are harmful, but some species can produce toxins that can cause serious illness or death in pets, livestock, and wildlife. Some studies suggest these toxins can also make people sick and in sensitive individuals also cause a red, raised rash or irritation.

Although these toxins are not absorbed through the skin, a red, raised rash or irritation of the skin and eyes can develop after contact with toxins in the water. If affected water is swallowed, you may experience one or more of these symptoms: headaches, cramps, diarrhea, nausea and vomiting, numbness, dizziness, fever. 

Children and pets are at increased risk of exposure because of their size and level of activity. The most severe reactions occur when large amounts of water are swallowed. Symptoms of exposure can mimic food poisoning. Food poisoning symptoms usually go away fairly quickly once your body gets rid of the spoiled food. 

Additional information about cyanotoxins is available online:

How You Can Prepare
Boiling water is not an effective method of removing cyanotoxins. Cyanotoxins are not absorbed through the skin, so daily tasks like washing hands, bathing, cleaning dishes, and laundry pose no health risk.

It is important to be ready ahead of time for possible emergency situations – including a Do Not Drink Advisory – by preparing an emergency water supply for yourself and your family.

Creating and storing an Emergency Water Supply 

  • Store at least one gallon of water per day for each person and each pet. You should consider storing more water than this for hot climates, for pregnant women, and for persons who are sick.
  • Store at least a three-day supply of water for each person and each pet. Try to store a two-week supply, if possible.
  • Observe the expiration date for store-bought water. Replace non-store bought water every six months.
  • Store a bottle of unscented liquid household chlorine bleach (label should say it contains between 5-6% and 8.25% of sodium hypochlorite) to disinfect your water,if necessary, and to use for general cleaning and sanitizing.
  • Print water-related CDC flyers to keep in your kit:

Please contact your respective public water provider with questions related to the UCMR4 testing program, or requests for results:

  • City of Hillsboro: 503-615-6702; E-mail
  • City of Forest Grove: 503-992-3258; E-mail
  • City of Beaverton: 503-526-2220; E-mail
  • Tualatin Valley Water District: 503-848-3000; E-mail