We’ve made mention (here) of  recent news on drinking water contamination, such as the recent NY Times article, “That Tap Water Is Legal but May Be Unhealthy,” making use of a lot of publicly available data.  The discussion largely revolves around increases in pollution in recent decades.

This issue provides an opportunity for adding other crucial information to the mix.

One point is the importance of correlating drinking water data with water sources, comparing protected watershed areas to rivers receiving wastewater discharges, for example, as a means of helping decide where to best put scarce resources.

Another important point, not really being brought out as it should in this recent news about drinking water, is that dual water systems are an approach worth considering to address these contamination problems.  As noted here (pdf file):

Dual water systems feature two separate distribution systems that supply potable water through
one distribution network and non-potable water through another. The two systems work independently of each other within the same service area. Using dual systems can boost public water supplies because they lessen the burden on drinking water systems because they do not have to provide water treated to drinking water standards for activities such as toilet flushing, firefighting, street cleaning, and irrigating ornamental gardens or lawns. In addition, dual water systems have the potential to save communities money because water can be used for more than one purpose thus reducing consumption of potable water.

In this scheme, potable treatment systems can be smaller than necessary to meet all of a community’s water needs, helping increase the cost-effectiveness of producing very high quality drinking water using advanced treatment technologies.  Put another way:  do we really need to flush our toilet with water clean enough to drink?