water system that requires payment, before September 1 of the fiscal year following the fiscal year in which the costs were incurred. The invoice shall indicate the total hours expended, the reasons for the expenditure, and the hourly cost rate of the local primacy agency. The invoice shall not exceed the total costs to the local primacy agency of enforcement activities specified in this subdivision. Notwithstanding the reimbursement to the state board of enforcement costs, if any, pursuant to Section 116577, any public water system under the jurisdiction of the local primacy agency shall also reimburse the local primacy agency for enforcement costs incurred by the local primacy agency pursuant to this section. The local primacy agency shall not be entitled to enforcement costs pursuant to this subdivision if a court determines that enforcement activities were in error. “Enforcement costs” as used in this subdivision does not include “litigation costs” as used in Section 116585.