21.05.060 Unreasonable Preferences or Advantages Prohibited

No utility shall make or give any undue or unreasonable preference or advantage to any particular person, company, firm, corporation or locality, or to any particular character of traffic or service in any respect whatsoever, nor subject any particular person, firm, corporation, company, or locality, or any particular character of traffic or service to any undue or unreasonable prejudice or disadvantage in any respect. No utility, directly or indirectly, by any special rate, rebate, drawback, or other device or method, shall charge, demand, collect, or receive from any person, firm, company, or corporation, a greater or lesser compensation for any service rendered or to be rendered than it charges, demands, collects, or receives from any other person, firm, company, or corporation for doing a like and contemporaneous service under the same or substantially similar circumstances and conditions. Nothing in this chapter shall prohibit a utility from entering into any reasonable agreement with its customers, consumers, or employees or from providing for a sliding scale of charges, unless the same is prohibited by the terms of the authority under which such utility is operated. No such agreement or sliding scale shall be lawful unless and until the same shall be filed with and approved by the Commission.