The duration for which a verbal warning stays on record for speeding can vary depending on the specific law enforcement agency and its policies. In many cases, verbal warnings are not officially recorded, and they are more like informal advisories given by an officer to remind you of the rules and regulations.
However, if the officer mentioned that the warning will stay "in house," it could mean that the information might be recorded within the police department's internal database for a limited period. This could potentially be used for reference if you are stopped by the same department's officers again in the future. It is unlikely to show up on your official driving record, which is used by insurance companies or for employment background checks.
It's important to note that different jurisdictions and police departments may have different policies, so there is no universal answer to this question. To get accurate information about the specific policies and duration of a verbal warning within that police department, you may want to reach out to them directly or consult local traffic laws and regulations.