Understanding new tax charges for California online stores?

Topic summary

Online store owners in California are seeing unexpected tax combinations on in-state orders, including both origin-based (Orange County) and destination-based (city/county) taxes plus state tax. They are unsure if recent law changes or system settings are causing double-charging.

Example reported: An order shipped to Modesto showed charges for Ceres City tax, Stanislaus County district tax, Orange County local tax, and California state tax. The merchant expected an Orange County component due to store location but is surprised by simultaneous destination-area taxes.

Another case: Orders shipped to Redwood City include Redwood City and San Mateo County taxes (expected), but some also add Orange County tax while others do not. This inconsistency appears in reports without a clear pattern.

No confirmation of any new California tax law is provided, and participants could not find additional guidance. The issue remains unresolved, with open questions about whether it is a legal change or a tax configuration/reporting problem.

Summarized with AI on February 1. AI used: gpt-5.

Good Morning,

I have 2 stores in California and have noticed some new taxes being charged to customers in California.

For example: there was an order going to Modesto, Calif and there is a charge for Orange County (store is located there so expected), Ceres City tax, Stanislaus County Dist tax, Orange county local tax, California State tax? Did some laws change?

I too am running into this issue with running a report. By that logic - all would pull for Orange County Co Tax since I am operating out of orange county. But this is not the case for all orders. I have orders shipped to Redwood city in Norcal that’s charging Redwood City tax, San Mateo County which is correct. But why it also charge for Orange county tax and not other orders going to San Mateo.
I can’t find any further information on this either.