And what about electricity or water debts?

In this case, debts will go with the person who signed the contract, and therefore the seller will be liable. However, electricity and water can be cut off if they have not been paid for.

The buyer can sign a new contract in their own name  with the supply company and remain unaffected by the debts. However, in practice it is most often cheaper to pay the bills and ensure supply than litigating with the company.

Again, a competent lawyer should check this.