Q: Can I raise the rent for a tenant who gave a 30 Day notice to vacate and now wants to take it back and add a roommate?

A: In California, if a tenant is on a month-to-month rental agreement, you generally have the right to raise the rent with proper notice. However, there are some limitations and considerations:

1. Rent control: If the property is subject to rent control ordinances, there may be limits on how much and how often you can raise the rent. Check your local rent control laws.

2. Rent increase notice: You must provide the tenant with a written notice of the rent increase at least 30 days before it takes effect if the increase is 10% or less. If the increase is more than 10%, you must provide at least 60 days' notice.

3. Retaliatory rent increases: You cannot raise the rent in retaliation against a tenant for exercising their legal rights, such as requesting repairs or filing a complaint with a government agency.

4. Discrimination: Rent increases must not be discriminatory based on the tenant's race, religion, national origin, disability, sexual orientation, or other protected characteristics.

Regarding the tenant's request to add a roommate, you have the right to screen the new roommate and have them sign a new rental agreement. You can choose to create a new month-to-month agreement with both tenants' names on it.

As for the rent increase amount, if the property is not subject to rent control, there is no specific limit on how much you can raise the rent as long as you provide proper notice and the increase is not retaliatory or discriminatory. However, it's advisable to keep the rent in line with market rates and to maintain a good relationship with your tenants.

It's always best to consult with a local real estate attorney or a landlord-tenant legal expert to ensure compliance with California laws and local ordinances.