Project scope: landscaping, new fence, new plumbing (from the main and in the house), new electrical, converted from oil to gas, new HVAC, water heater, reconfigured upstairs to include 2 BRs and a real full bath, gutted kitchen, new bathroom on 1st floor, refinished HW floor, new roof and gutters, repair fascia, soffits, siding, painting, concrete work on sidewalk and driveway, new basement windows, new door and windows on detached garage.

I would recommend MainLine Plumbing, message me if you'd like contact info.

Step one is to study your state landlord tenant regulations.

No, no, no...I see these all the time in properties...houses and foundations move and shift over time...in my area, for example, all of our floors are sloped because of settling and foundation movement...no big deal...have a contractor look at them if it really bothers but I would say look at the HVAC/electrical/plumbing/sewage in the basement (I've had that in one of my properties)/those type of critical issues...those are way more important than cracks in the wall...just my opinion BTW!

There are several ways to structure these deals, but to be in compliance with current regulations and to be very fair and clear to all parties involved, your terminology and the clauses of your agreements actually matter.

Read and learn your state landlord tenant regulations.

Another thing to consider is tenants friendly laws and regulations in CA.

I especially thoroughly check out the plumbing.  

Study and learn the appropriate state landlord tenant regulations if you want to do it right.Based on the circumstances you should be seriously looking to get rid of this tenant.

When the tenant has noticed that the plumbing or pipelines are prone to damage, the tenant should inform the landlord.