Lead Monitoring in Service Lines and Buildings

Development of a harmonised monitoring strategy for determining the release of lead into drinking water in service lines or indoor installations


Following the adoption of the new European Drinking Water Directive 2020/2184, the limit value for lead in drinking water will be changed from 10 to 5 μg/L. This is a standard value for the average weekly lead intake of consumers.

The results of the RDT (Random Day-time) sampling method, which has been widely used for many years, show that the average background concentration of lead in drinking water in the Netherlands is approximately 0-2 µg/L. This is partly the result of targeted actions by the drinking water utilities in the past decades to replace lead-containing materials in their treatment and distribution systems with lead-free alternatives. As a result, the lead that is still present in drinking water systems can mostly be found in service lines and residential water systems, more specifically in buildings from before 1960.

Lead pipes being replaced with lead-free alternatives

Lead pipes being replaced with lead-free alternatives

The joint Dutch water utilities have expressed the need for a harmonised sampling strategy for lead in service lines and water systems in buildings, in addition to the legally prescribed RDT sampling regime for lead in distribution areas. More specifically, the sampling methodology should allow for a better estimate of the average weekly lead intake of  individual consumers.

Goals & Objectives

The main objective of this project is to develop a widely supported, harmonised monitoring strategy for determining the release of lead into drinking water in service lines or pipes and/or appendages in indoor installations. The overall goal is to achieve a significant reduction of potential lead exposure via drinking water.


The starting point for drawing up a uniform step-by-step plan for lead sampling of connecting pipes and indoor installations is the Flemish Action Plan for Lead Prevention in Drinking Water, as developed by the Flemish Environment Agency. The Dutch approach differs from the Flemish action plan on a number of points.


Four specific goals of lead sampling have been defined, each with two sub-goals:

  1. determining whether lead is present
  2. determining where lead-containing compounds are located
  3. estimating the exposure risk
  4. consulting/advising

Different sampling strategies have been developed for each sub-goal. Subsequently, possible outcomes, conclusions and possible courses of action have been defined for each combination of goal and sampling strategy.

A uniform sampling protocol has been written for carrying out lead sampling which can be used by both drinking water laboratories and commercial parties. Based on all available information and discussions with drinking water utilities and laboratories, a step-by-step plan has been drawn up that can be used by all drinking water utilities. The step-by-step plan is described on the basis of six flowcharts.

What's Next?

This project is linked to a modelling study by KWR Water Research Institute into lead emissions from appendages in indoor installations and service lines. This study can produce additional relevant data in the follow-up phase, on the basis of which the step-by-step plan presented in this project can be further refined.

The report of this project is submitted to the Dutch National Public Health Authorities (RIVM) via the Water Quality Advisory Group of the Dutch drinking water sector, as part of the revision process of the Dutch Drinking Water Act and Regulations, following the new EU Drinking Water Directive, which was adopted in 2020.

More Information

Simple sensors which can accurately determine the lead concentration in drinking water online and in real time are currently not available. The instruments with which measurements can be carried out online and on-site are (too) complex and can therefore not be used without supervision for a longer period of time in e.g. residential houses or apartment buildings.

On our Resources Pages, you can find more information about online lead monitoring and the latest updates on technology developments. Or sign up for our alert services via the button below, and we will inform you when new online lead sensors become available.

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