Hi.
Thanks for your query.
Noted the history of traveling from Texas to Southern California, think of tap water causing you some problems like stomach pain, instant need to have a BM, for a week, and the gut is still not alright in spite of bottled water, wants suggestions...
As per the history you have given this looks to be traveler's
diarrhea and can be due to water borne or food borne infection.
Hence I would advise you the following:
Consult a Local Doctor to get a clinical evaluation, examination and investigations of stool and blood.
Get started on proper prescription based antibiotics,
metronidazole, probiotics and symptomatic treatment as needed.
Try boiled for 20 minutes and cooled water.
Maintain good hydration and proper electrolyte balance.