There is no need immediately to notify your car insurance company of the DUI arrest. Wait to see what happens with the case. If you can get the DUI charges dismissed (or reduced), and win the DMV hearing, you most likely will avoid hikes in your auto insurance premiums or cancellation of the policy.
You are indeed innocent till proven guilty.

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There is no need immediately to notify your car insurance company of the DUI arrest. Wait to see what happens with the case. If you can get the DUI charges dismissed (or reduced), and win the DMV hearing, you most likely will avoid hikes in your auto insurance premiums or cancellation of the policy.
You are indeed innocent till proven guilty.

If I don’t Tell Them, Will My Insurance Company Still Find Out? How?

In general, nobody automatically notifies your auto insurance company of the DUI arrest. But if you are convicted, the insurer will almost certainly find out, and will do so one of two ways. The first is periodic review. Most car insurance companies check DMV records every few years, or when you apply for (or seek renewal of) a policy. When they do a periodic check, they will see a DUI conviction or DMV license suspension (if they don’t know already), and take action.

The second way the car insurance company will discover a DUI conviction is if you have to ask them for an SR22. If your California drivers license is suspended (either because of a DUI conviction in court, or because of losing your DMV hearing), the DMV will require you to provide an SR22 before reinstatement of your license. Moreover, you will have to keep a valid SR22 on file with the DMV for 3 years as a condition of maintaining your California drivers license.

Where do you get an SR22? From your car insurance company. When you go to the insurance company asking for an SR22, they will demand to know why you need it. Moreover, this will trigger them to do a DMV records check. They will discover that you suffered a license suspension because of a DUI, and take whatever action they deem appropriate.