On 14 February 2017 the Federal Environment Ministry published the "guidelines on compliance with the requirements of the Drinking Water Ordinance in the testing and evaluation of radioactive substances in drinking water", which recommend a course of action for water suppliers and enforcement authorities. The competent federal and Länder authorities cooperated with experts from water boards in drafting these guidelines. They aim to support local authorities by contributing to a uniform implementation of the regulations on the monitoring of radioactive substances and by serving as recommendations for action when parameter values in drinking water are being exceeded.
The 2012 guidelines on the testing and evaluation of radioactive substances in drinking water required revision following the implementation of Council Directive 2013/51/Euratom laying down requirements for the protection of the health of the general public with regard to radioactive substances in water intended for human consumption. The Third Ordinance amending the Drinking Water Ordinance, which came into force in November 2015, implemented this Directive into national law and, for the first time, introduced requirements for the protection of the public as regards radioactive substances in drinking water. This defines parameter values for the concentration of radioactive substances, specifications on reference activity concentrations and minimum detection limits for the relevant radionuclides, but also sets out requirements for sampling or frequency of monitoring which enable uniform testing. In addition, it lays down a framework for suitable national monitoring strategies. The water supply companies are obliged to carry out inspections of drinking water for radionuclides of natural origin. The obligation to carry out tests only affects "central waterworks" (a-plants) in order to avoid disproportionate expenditure for small business operations. Testing procedures in "decentralised small waterworks" (b-plants) may be ordered accordingly if higher concentrations of radioactive substances are to be expected. These new regulations form the basis for taking action to reduce radioactive substances in drinking water in individual cases and for ensuring the high quality of drinking water with regard to radioactive substances.
Depending on the individual geological conditions, all rocks and soils contain natural radionuclides. These radionuclides can enter surface water and groundwater (including bank filtrate, fissure and tunnel water) to varying extents through complex solution and transport processes. The activity concentrations of the natural radionuclides in these waters and the relative activity proportions of the single nuclides can vary within wide limits. Radiation exposure to radionuclides in drinking water is very low on average and health hazards can generally be ruled out. The fluctuation range of the concentrations of natural radionuclides in drinking water varies considerably from region to region. Consequently, precautionary measures to reduce these concentrations may be appropriate in individual cases. The testing and evaluation of radioactive substances in drinking water as laid down in the guidelines on compliance with the requirements of the Drinking Water Ordinance may only be carried out by authorised testing and examination bodies. The competent federal state authority only grants approval to a testing and examination body if the test laboratory is accredited for testing according to the Drinking Water Ordinance. It is also possible that laboratories obtain accreditation for the testing of single parameters only. The accredited laboratories have to participate in quality assurance programmes, for example in the interlaboratory comparisons of the Federal Office for Radiation Protection (BfS). The requirements for the accreditation of sampling and test laboratories have recently been revised.
The Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU), the Federal Ministry of Health (BMG), the Federal Office for Radiation Protection (BfS), the German Environment Agency (UBA), the responsible Länder authorities as well as the German Technical and Scientific Association for Gas and Water (DVGW) and the Federal Association of the German Energy and Water Industries (BDEW) recommend the application of the guidelines – within the framework of testing and evaluating the drinking water quality – in their present form, which corresponds to the state-of-the-art of science.