Legal Question in Landlord & Tenant Law in California

Good morning, She can give notice of the problem in writing, explain why it is a pressing issue and give a reasonable time for it to be repaired. (2-8 weeks is my estimate for a reasonable repair time barring other circumstances.) It might help if she includes an estimate from a licensed contractor. If the landlord fails or refuses to address the issue it must be a "habitability" issue before she can take action, (ie. if she cannot use the tub at all it may rise to that level. There is no definitive answer.) The action she can take is to request a rent reduction or she can advise the landlord she wishes to fix it herself and deduct it from her rent. She should not, however, deduct it from her rent if the landlord does not agree because I suspect there is another room where she could take a bath and/or shower if she needs to - thus in all likelihood, not rendering this a habitability issue. She can later try to recoup the money in small claims court but she will also have established a tense relationship with the landlord.