Inspection and maintenance

On-site inspections and tests should be carried out twice a year by competent experts / inspectors in accordance with DIN 13564-1 and DIN 1986-3 for manual backwater valves (for wastewater without sewage) and, in the case of Type 3 electric backwater valves (for wastewater with sewage), by qualified competent experts / inspectors. If necessary, appropriate maintenance measures must be carried out to ensure compliance with the tightness requirements.

The following work must be carried out:

• Removal of dirt and deposits
• Checking seals and sealing surfaces to ensure they are in perfect condition; replacing seals if necessary
• Checking the mechanical aspects of the moving sealing components and re-lubricating them if necessary
• Verify the tightness of the operating seals by means of a functional test in accordance with DIN EN 13564-2, using a test pressure of 1 kPa and a test duration of 10 minutes, and in accordance with the manufacturer’s instructions

Backwater valves in accordance with DIN EN 13564-2 Type 3 must be inspected and maintained by competent skilled persons. Other types of backwater valves must be inspected by competent experts / inspectors. 

The following work must be carried out:

• Check that the operational closure is working
• Confirm the emergency closure by closing and opening it

Drainage systems must be operated and maintained in accordance with DIN 1986-3, DIN EN 752-7 and the provisions of the relevant wastewater regulations. They must be checked for proper functioning and the absence of defects through regular condition assessments, and kept in a serviceable and safe condition through appropriate maintenance measures. All available relevant information regarding a drainage system must be recorded and assessed. This forms the basis for the subsequent planning of all further activities. 

Examples of such information include:

• Creating or updating an as-built plan of the property drainage systems beneath the building’s foundation slab and outside the building, specifying the type of wastewater discharged
• Materials of the main drainage pipes and specification of the nominal sizes (DN)
• Location, depth and height, relative to sea level (NN), of the chambers and inspection chambers, including their nominal sizes and connections
• Location of drainage elements, such as yard drains, floor drains, backwater valves and sewage lifting stations
• Location, type and size of wastewater treatment plants
• Water protection areas, medicinal spring protection areas and/or water abstraction areas