Recently in the news there have been banner headlines about lead contamination in the tap water distributed by the city of Flint, Michigan.
A story on January 23 was headlined, “Flint mayor (Karen Weaver, D): Lead fix could top $1.5 billion.”
It would appear to any knowledgeable engineer that the problems they have had are the predictable result of failure on the part of those in charge to exercise long-accepted and standard-maintenance operating practices. The story, by Tammy Webber of Associated Press, indicated that the city managers had decided in 2014 to quit buying water from Detroit and instead pump water from the Flint River. Because of pollutant chemicals in that water, one would expect to need added anti-corrosion chemicals along with the usual sanitation ones.
An earlier news story included a picture of water pipe ends with substantial build-up of deposits inside the pipe. This probably could have been prevented by a proper chemical treatment program, but it seems that the funds were diverted to other, politically important uses, or were missing because of the departure of high-paying manufacturing jobs from the area and the associated reduced tax revenues.
One of the main complaints of citizens, as shown on TV news, are the results of lead contamination. It is most likely, and implied in that story, that the lead contamination is the result of leaching of the lead from the waterline joint seals by the polluting chemicals in the new water being used. By explanation, cast-iron lines which were installed many years ago, like before World War II, were connected by bell and spigot slip joints that were sealed with lead poured into the joint. After the war the pipe used was called ductile iron or they were steel and the joint seals were a rubber gasket, which was much more seal effective and allowed for some expansion in the pipe with temperature change (such movement could crack the lead seals to allow leaks).
Another source of lead contamination was reported to be the use of lead pipe for the service lines connecting the buildings to the main distribution lines. That is a first for my experience. Lead pipe was previously used for sewer lines in the buildings, but not for water lines, in my experience. Even that has been replaced with the PVC in recent decades.
Still later, plastic, such as PVC or PE pipe, with the same bell-and-spigot connections with rubber seals, came into common usage. These have less tendency to expand and contract and more flexibility to move slightly with ground shift. They also have the ability to tolerate freezing because of that same feature. Also, with the plastic there is no tendency to find rust in the water from the pipe as with iron or steel.
Actually the situation in Flint is a more pronounced example of what is, or could be, going on in many cities where normally accepted maintenance procedures are neglected or postponed. Even in Tulsa, which is a much newer city than Flint, there have been a large number of line breaks reported which were blamed on soil shifting because of temperature changes.
All this is a glaring example of the usual tendency of officials of government at all levels, from schools to the White House, to neglect the ongoing maintenance necessary to keep facilities usable for the original purpose. Then when those facilities become overly expensive to restore, they resort to bond issue financing, at great added expense, to restore or replace the facility. Their attitude seems to be to let the populace (taxpayers) pay the added expense of the interest and fees that become involved in those bonds.
A further problem is, in my opinion, the exorbitant salaries and expense accounts that such officials have heaped on them. The budgets could be thus reduced into revenue amounts.