Maintenance of treatment facilities is a set of special measures to maintain optimal parameters of the treatment facilities and maintain high operational reliability of the treatment system. The maintenance of treatment facilities includes compliance with the technological process during wastewater treatment, inspection of installed treatment equipment, diagnostics, troubleshooting and require stable monitoring by specialists to maintain high reliability of systems and environmental conditions. We conclude a contract for long-term maintenance and preventive maintenance of our equipment and existing ones. This agreement provides for priority in the departure of the service team for maintenance and low prices for consumables, work and equipment.