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About Proposition 65


What is Proposition 65?

In November 1986, California voters approved a ballot initiative to address concerns about exposures to toxic chemicals. That initiative became the Safe Drinking Water and Toxic Enforcement Act of 1986, better known by its original name, Proposition 65 or simply, Prop 65.

New regulations affecting Proposition 65 were adopted in August 2016 and will take full effect in August 2018. Changes to the law impose additional requirements for products sold in California, including:

Please note that any modifications made to Watts and its brands’ product labels and packaging do not reflect any changes to our products. We will continue to provide high-quality solutions used to safely convey, conserve, and manage water.


What does Proposition 65 require?

First, it requires the State of California to publish a list of chemicals that are known to the State of California to cause cancer, birth defects, or other reproductive harm, and requires businesses to inform Californians about exposures to such chemicals. These chemicals can be in the products that Californians purchase, in their homes or workplaces, or released into the environment. It also requires the state to maintain and update the list at least annually. As of July 7, 2017, more than 900 chemicals and materials, including many metals and plastics, have been listed.

Second, it requires businesses to provide a "clear and reasonable" warning before knowingly and intentionally exposing anyone to a listed chemical. This warning can be given in several ways, such as by labeling a consumer product, posting signs at the workplace, publishing notices at a rental housing complex, or publishing notices in a newspaper.


What does a Proposition 65 warning mean?

A warning means that the business issuing it is complying with Proposition 65’s requirement to identify the presence of one or more listed chemicals, even in trace amounts. Watts and its brands have chosen to label all of their products available in North America. We use language approved by the State of California as follows:



What kinds of chemicals and materials are on the list?

The list contains a wide range of naturally occurring and synthetic chemicals that are known to cause cancer or birth defects or other reproductive harm. These chemicals include additives or ingredients in pesticides, common household products, food, drugs, dyes, or solvents. Listed chemicals may also be used in manufacturing and construction, or they may be by-products of chemical processes, such as motor vehicle exhaust. The complete Proposition 65 List is available at


How can I get more information?

The California Office of Environmental Health Hazard Assessment, OEHHA, maintains a comprehensive website at, which explains the law and offers a list of all the chemicals and materials.

You can call the Office of Environmental Health Hazard Assessment's Proposition 65 Implementation Office at (916) 445-6900 or send email to