Water Treatment

Water Treatment

Water treatment and water disposal! Why?

In the last 15 years, special waste water laws have evolved within German federal law and legislation at state (land) level. For the services the ETRAS Group provides the requirements sets for indirect dischargers are relevant. Indirect discharge refers to the fact that waste water (including water used for cleaning facades) is later discharged or fed indirectly into inshore waters via a sewerage system and through a purification plant..

Given the deposits of harmful substances that have often accumulated over decades on facades in conjunction with substances from various paints cleaning or stripping work results in very high concentrations of harmful substances, in particular heavy metals. All municipalities in Germany have determined similarly graded limits for the admissible concentration of harmful substances in waste water.

When granting permission to discharge, the authorities must ensure compliance with the so-called indirect discharger regulations or similar provisions. Since these limits are almost always exceeded during façade work it is absolutely crucial to capture the soiled water that arises and clean it with a suitable and authorized treatment plant (like the ETRAS one) and to dispose of the harmful substances and sludge from façade cleaning in an orderly manner.

The legal basis for mandatory water treatment is the German Act for the Organization of the Water Supply (WHG or German Federal Water Act) of November 12, 1996 (Federal Legal Gazette. p. 1696).

For the work of the ETRAS GmbH, section 7a of the WHG applies.

Here is an excerpt:
“Permission to discharge waste water may only be granted if the concentration of harmful substance is kept to the possible minimum using the most suitable method and the most up-to-date technology available. Section 6 remains unaffected.”
In consultation with the Bundesrat the Federal Government sets out requirements in the form of legal provisions that are aligned to the current level of technology. These requirements can also be determined for the place of the waste water occurring or prior to its mixing.


Other relevant laws and regulations exist in addition to the WHG. In the case of the State of North-Rhine Westphalia, for example, these are:

• Waste Water Origin Directive of July 3, 1987
• State Water Act of June 9, 1989
• Indirect Discharger Regulation of Sept. 25, 1989
• MURL Decree on "facade treatment" of Nov. 13, 1991
• Municipal bylaw on drainage


In the "MURL decree" (issued by the Ministry for the Environment, Environmental Planning and Agriculture) the topic of dirty water and sludge arising from facade cleaning but also its treatment and disposal is specifically mentioned.

Every German state has similar regulations. Generally speaking, these regulations are known under the more general term "indirect discharger regulations". On the whole, these provisions vary little from state to state. The State of Hesse goes relatively far with its directive "Requirements for the capture and treatment of waste water occurring during the cleaning and stripping of facades" from 22 June, 1992.

However, regardless of the above compliance with the waste water bylaws of the respective municipality must be ensured. Every town and district has its own bylaws. The aforementioned limits for the discharging of dirty water including dirty water from the facade must be met under all circumstances.

Before work begins on the façade, regardless of whether the masonry is being cleaned or paint being stripped the building site must be registered with the responsible authorities (Environmental Protection Agency, Water Protection Agency) and permission for discharging water be secured.

Generally speaking this permission is also necessary when only water is used for cleaning and no chemicals are involved.


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