For wastewater conveyance and treatment, charges for service are based on annual flows from participating cities into each system.

Each year, we establish budgets to operate, maintain and improve our wastewater systems. Similar to the water system, the NTMWD regional wastewater conveyance (interceptor) and treatment systems are experiencing increasing fixed costs to address growing capacity needs and regulatory requirements. Critical repairs, system expansions and condition assessments require investments now to avoid the risk of overflows that can impact the environment and result in costly fines.

Charges are based on current budgeted expenditures and are allocated to each city at the beginning of the year based on estimated flows. At the end of the year, the actual cost for each city is determined based on actual flows and final billings are adjusted accordingly.