Legal Question in Wills and Trusts in California

You need to provide more information. If there are any cash assets in the estate, the administrator may have used those assets, which normally would have gone 50-50% to the two heirs, so you would in effect pay for half the cost. You could try to get the administrator to use only the funds due to the other heir on the argument that the work only benefits that heir.

An estate cannot make improvements to estate property. The administrator or executor can only prevent waste (repair damages that can diminish the value of the property such as a hole in the roof). Your first question should be, was the old septic system functioning? If it was functioning, then the administrator or executor acted improperly and the court can surcharge him/her for the expense. If the septic system was not functioning or was a hazard to public health or codes, the administrator or executor can make the repair/replacement and charge it to the estate. The next question is whether the septic system could be repaired rather than replaced? If it could be repaired at less expense than replacement then it should have been repaired rather than replaced. If the septic system is properly replaced or repaired, the cost is split according to the beneficiaries share of the estate.