DIN 1986-100:2026-11

Safe planning, sizing and operation of drainage systems for buildings and properties

DIN 1986-100 contains national provisions for drainage systems for buildings and properties in conjunction with DIN EN 752 and DIN EN 12056. It supports planners, engineers, building services specialists and contractors in the planning, sizing, installation and maintenance of wastewater and rainwater systems. Particular emphasis is placed on backflow protection, flood safety, emergency drainage and rainwater management.

What is DIN 1986-100 about?

The standard defines the requirements for property drainage systems inside and outside buildings. It focuses on the planning and sizing of wastewater, rainwater and combined wastewater systems, protection against backflow and flooding, and the safe discharge and treatment of different types of wastewater. The standard also specifies requirements for roof drainage, emergency drainage, retention drainage, lifting systems, backflow prevention devices, ventilation systems and wastewater treatment systems.

The 2026 edition also places greater emphasis on requirements relating to climate adaptation, flood prevention and rainwater retention.

Topics covered

• Planning of property drainage systems
• Wastewater, rainwater and combined wastewater systems
• Roof drainage and emergency drainage
• Retention roofs and rainwater retention
• Protection against backflow and flooding
• Stacks, underground pipes, collecting pipes and ventilation systems
• Wastewater lifting systems and backflow prevention devices
• Leak testing, fire protection and sound insulation
• Separator systems, on-site wastewater treatment systems and wastewater collection tanks

Practical relevance

Heavy rainfall events, backflow from public sewers and increasing requirements for rainwater management are making professional drainage planning increasingly important. DIN 1986-100 helps users to size drainage systems safely and reduce flood risks.

The provisions on backflow level, emergency drainage, retention roofs and flood-risk assessments are particularly relevant because they directly affect the protection of buildings and properties. At the same time, the standard provides a consistent basis for sizing rainwater and wastewater systems under current climatic conditions.

Changes compared with DIN 1986-100:2016-12 and DIN 1986-4:2019-08

The 2026 edition has been extensively revised. The most important changes include:

• Integration of the content of DIN 1986-4:2019-08 into the standard
• Fundamental revision of the section on protection against backflow
• Fundamental revision of the sizing of rainwater systems
• Expanded provisions on emergency drainage, balconies, loggias, roof terraces and terraces
• New provisions on retention roofs, rainwater retention and flood-risk assessments
• Extensive revision of stacks, backflow protection and retention spaces
• New annexes on leak testing, usability of construction products and graphical representations

Target audience

• Building services design specialists
• Urban water management engineers
• Plumbing, heating and air-conditioning contractors
• Civil engineers and architects
• Municipalities and public-sector contracting authorities
• Experts and testing bodies
• Operators of buildings and properties
• Drainage and rainwater management professionals

Conclusion

DIN 1986-100 provides the central basis for the planning, sizing and operation of drainage systems for buildings and properties. With its expanded requirements for backflow protection, emergency drainage, rainwater retention and flood prevention, it supports safe, future-proof drainage planning under the conditions of climate change.

This document replaces DIN 1986-100:2016-12 , DIN 1986-4:2019-08 .

And replaced by 2026-11 for:: DIN 1986-100:2016-12 , DIN 1986-100:2025-06 , DIN 1986-4:2019-08 .