Heavy metals such as cadmium, copper, lead and zinc are the critical metals in domestic wastewaters. Depending on the sewerage concept, the metals accumulate in different environmental compartments. With the combined sewer system, most commonly applied, the major part of the metals is bound to the sludge during sewage treatment. If the sludge is used in agriculture, the metals are enriched slowly in the top soils. With separate sewer systems, the metal loads to the receiving waters are increased, finally leading to accumulation in the sediments. If the new concept for the infiltration of runoff waters is applied, rapid and concentrated accumulation at the infiltration sites will occur. As a short term measure, new adsorptive elements in infiltration facilities would allow to control the accumulation. However, whatever measures are taken, the deposition of heavy metals in the environment cannot be avoided as long as no further efforts are made to reduce metal emission at the source. On the long run, copper and zinc are considered to be inadequate materials for roofs and runoff installations for ecological reasons.