Registry of water utility water-quality data


In order to safeguard the quality of drinking water in the Netherlands, standards and processes for monitoring drinking water and its sources are set out in legislation and regulations (including the Drinking Water Regulations and the Drinking Water Decree). To control whether the water supplied by the drinking water utilities meets the legal requirements, the drinking water quality data need to be recorded. REWAB (the Dutch acronym for the ‘registry of water utility water-quality data’) is the system used by the Dutch drinking water utilities to record and assemble the drinking water quality data.

Monitoring process

The REWAB project safeguards the monitoring process of drinking water in the Netherlands. This process comprises two phases:

  1. In the first phase, a measurement programme is set up by drinking water utilities. This programme designates which substances and biological parameters will be measured in the upcoming year, at which locations, and with which frequency (the number of sampling events per year). This measurement programme is entered into the REWAB web application by drinking water utilities and water laboratories. The Human Environment and Transport Inspectorate (ILT) is responsible for approving the measurement programmes. The National Institute for Public Health and the Environment (RIVM) provides the required reports from REWAB. After the measurement programme has been approved, the drinking water samples can be taken, and the different substances analysed over the course of the year.
  2. In the second phase, the aggregated measurements (minimum, maximum, average, etc.,) are entered into REWAB. An automatic process has been set up for this, so that the measurements can be sent directly from the LIMS of the drinking water laboratories to REWAB. RIVM and ILT then assess these data.

Water quality data

The data that are entered into REWAB can be used for research. But there are conditions attached. The objective and the scope of the research must be clearly established for each research project. Vewin will then examine whether the REWAB data may be used for the research. Since the data have already now been entered into REWAB for many years (from 1992), trend analyses for instance can be easily carried out. The biggest challenge in this context is to maintain the data quality at the highest level possible – for example think of the unique identification of the thousands of substances that are analysed in the water. The REWAB project, besides supporting the registration of water quality data through the web tool, is therefore also focused on safeguarding the quality of these data.