When starting is it normal for hair to stay slightly oily after baking soda wash?


Hey all! I’m just starting out, I’ve washed my hair with baking soda twice during the past 2 weeks and both times I come out of the shower with hair that’s more oily than I’d expect after a wash. I end up putting in cornstarch to help it look presentable. Is this normal for transition or am I doing the method wrong? Also we have hard water, so would a showerhead water filter just solve this too?

Thanks for your time!