This depends on your use case.
Ad targeting: You must apply Watt's suppression lists before activating any audience segment, and your privacy policy should disclose use of third-party data for advertising.
Email outreach: You bear CAN-SPAM compliance responsibility, including a functional opt-out mechanism and accurate sender information.
ICP analysis: The requirements are lightest — you primarily need a lawful basis for sharing your own customer data with Watt, typically covered by your existing privacy policy.
In all cases, Watt data is expressly prohibited from use in any eligibility determination under FCRA — meaning credit, insurance, employment, or housing decisions.