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Boil Water Notice: Wilder Reservoir Incident

 UPDATE 2/20/2020


Este informe contiene información muy importante sobre su agua potable.

Tradúzcalo o hable con alguien que lo entienda bien.


 On Tuesday, February 18, 2020 you were notified of the need to boil/disinfect all tap water used for drinking and cooking purposes. 

The City of Thousand Oaks’ Water System in conjunction with the State Water Resources Control Board, and/or the Ventura County Local Environmental Health Jurisdiction, has determined that, through abatement of the health hazard and comprehensive testing of the water, your water is safe to drinkIt is no longer necessary to boil your tap water or for you to consume bottled water. We apologize for any inconvenience and thank you for your patience during this process. 

Water Testing Update:

In the Boil Water Notice you were notified that passing bacteriological sample results needed to be verified before confirming that the water is safe to drink. Bacteriological samples were taken throughout the affected area on Tuesday morning, February 18, 2020. On Wednesday morning, February 19, 2020, a second set of bacteriological samples were also taken per the State Water Resources Control Board’s guidance. On Thursday morning, February 20, 2020 all of the results were finalized and it was confirmed that all of the samples passed, and they had good disinfection residuals. The presence of good disinfectant residuals combined with the absence of bacteriological contamination confirm that the water was and is safe to drink.

 For a copy of the notice, please click here.

For more information please visit the City’s website at or call:

City of Thousand Oaks: Paul Jorgensen, Water Quality Supervisor at 805-449-2499

State Water Resources Control Board, Division of Drinking Water at 805-566-6625

Local Environmental Health Jurisdiction, Ventura County at 805-654-2818


 POSTED 2/18/2020

The following information is a Boil Water Notice that was hand delivered to impacted residents.

Click the map to search the area under the Boil Water Notice:

 Wilder Resivor Boil Water Notice Map

If you live within the impacted area, and did not receive a notice, please follow the precautions listed below. If you do not live in the area identified above, your water is unaffected and do not need to boil it prior to consumption. 

February 18, 2020

Este informe contiene información muy importante sobre su agua potable.
Tradúzcalo o hable con alguien que lo entienda bien.

Failure to follow this advisory could result in stomach or intestinal illness.

Due to a water system disruption, a limited portion of the City’s water system experienced a short-term water outage event on Monday, February 17, 2020, at approximately 7:00 a.m. As a precautionary measure, the State Water Resources Control Board, Division of Drinking Water, in conjunction with the Ventura County Environmental Health Division, and Thousand Oaks Water Department are advising residents to use boiled tap water or bottled water for drinking and cooking purposes until bacteriological sample results are available on Thursday, February 20, 2020. The water outage lasted approximately two hours on Monday morning, and water was restored to the system after the City’s water crew members thoroughly flushed all water mains in the affected areas. On the morning of Tuesday, February 18, 2020, the City’s water quality staff took bacteriological samples at nine locations throughout the affected area and all samples had high disinfection residuals, which is a strong indicator of good water quality. The following practices are advised as a precaution until all sample results are returned. Once that occurs, water customers will be notified and this notice will be lifted.

DO NOT DRINK THE WATER WITHOUT BOILING IT FIRST. Bring all water to a boil, and let it boil for one (1) minute, and let it cool before using, or use bottled water. Boiled or bottled water should be used for drinking and food preparation until further notice. Boiling kills bacteria and other organisms in the water.
Optional alternative to include for prolonged situations where it fits.

• An alternative method of disinfection for residents that are not able to boil their water is to use fresh, unscented, liquid household bleach. To do so, add 8 drops (or 1/8 teaspoon) of bleach per gallon of clear water or 16 drops (or 1/4 teaspoon) per gallon of cloudy water, mix thoroughly, and allow it to stand for 30 minutes before using. A chlorine-like taste and odor will result from this disinfection procedure and is an indication that adequate disinfection has taken place.

• Water disinfection tablets may also be used by following the manufacturer’s instructions.

We will inform you when tests show that water is safe to drink and you no longer need to boil your water. We anticipate resolving the problem within the next couple of days.
If you are in need of bottled water, please contact the City at 805-449-2499.

For more information call:
• Water Utility contact: Paul Jorgensen, Water Quality Supervisor, 805-449-2499, 2100 Thousand Oaks Boulevard Thousand Oaks, CA 91362
• State Water Resources Control Board – Drinking Water Field Operations Branch- District Office at 805-566-6625.
• Local Environmental Health Jurisdiction: Ventura County at 805-654-2818.

Please share this information with all the other people who drink this water, especially those who may not have received this notice directly (for example, people in apartments, nursing homes, schools, and businesses).

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