La. Stat. tit. 45 § 848
Whenever any person engaged in furnishing gas, electricity or water shall demand of its patrons a cash security to protect the furnisher of gas, electricity or water from loss by reason of extending to such patron's gas, electric or water service, the furnisher shall pay to that patron, interest at the rate of five per cent per annum upon the amount of the deposit so long as it continues to hold or exact the deposit. The balance of the deposit together with earned interest shall be returned to the depositor, on demand whenever the service is discontinued, and any refusal or neglect to return the balance shall subject the furnisher of gas, water or electricity to the penalty of paying the consumer ten per cent per annum interest upon the deposit so retained after demand.
La. R.S. § 45:848