Legal Question in Landlord & Tenant Law in California

Unless you had wording on or with a paper attached to or enclosed with the check saying cashing the check was an acceptance of a settlement of all claims, her cashing the check does not waive any rights she has to a claim agaist you. Within 21 days after you regained full possession of the property [which also means your getting the keys back], you had to send her a list of all deposits you had, and any deductions you were taking and why. If you failed to do that, you will lose in Court even if she did owe back rent. You will want to try to settle with her.