Well Whiggy,
I remember just hot bad coffee could taste when made with the old MWRA water flavored by Canada Geese whose droppings enhanced the nature of the Watchusett Reservoir (the geese fed on landfills outside the Watchusett drainage area but squatted on the Watchusett) - it tasted like coffee filtered through a jock strap.
I'm quite glad that the EPA helped the MWRA come into the 20th century.
Randomgear -- are You sure you weren't drinking Cambridge water flavored by terriers and beagles walking around "Fresh Pond" after having been flavored by runoff from Rt-128 in Waltham
The comment about the EPA and the 20th C is a red herring -- the MWRA water was routinely tested and taste tested and it always came out near the top of big city water supplies. The Quabbin water is very clean it did tend to go down a bit when passing through the Wachusett whose watershed is not as well protected. However, the worst of the MWRA water quality problems came from leaky pipes in various dank locations.
Ah you say a leak is water flowing out -- true if its a major leak -- and its usually fairly soon visible. But in the older pipes the joints between the pipes could have just enough loss of integrity to allow water in a hole with the pipe submerged below the water table to get sucked into the pipe by the the venturi or Bernoulli Principle.
Water flowing though the pipe encounters some narrowing at the joint due to deposits accumulating over one hundred years -- the result is that to keep water from vanishing [conservation of mass] it has to speed-up in the vicinity of the joint. By speeding up it tends to locally lower the pressure and so can entrain air or potentially water from soil say frequented on the surface by packs of terriers. New methods of lining older pipes and the new ductile iron pipes being installed as new work and replacements are much tighter and much cleaner.
But the Big problem with the EPA is that the Legislation continually tinkered with by Congress is not updated to keep abreast of the changes in measurement technology. These changes can be considered revolutionary -- so that what in the 1960's when all this stuff started was considered heroic in state-of-the-art labs is now routine in field instruments which you can buy on Ebay. This causes one of those problems which Legislators -- typically Lawyers who are Math-adverse can't seem to comprehend.
As someone once said -- the solution to pollution is dilution -- which works in real life -- but not if the regulation says something such as "Thou shalt not permit any substance which causes cancer in lab animals to enter the food chain" Of course its trivial to prove that all substances which once existed [unless they decay to something totally innocuous] and once fell under the prohibition will eventually be found everywhere. As the old chemistry exercise proves -- you are very likely at this moment to have breathed some of the Oxygen Atoms which once fueled Leonardo's incredible brain.
Exercise for those interested which of the following is One Part per million, one part per billion or one part per Trillion of something else [within a factor or 2 to 3]:
a) a piece of ordinary paper next to the Millennium Tower
b) Binge watching TV for a year versus the time it takes to view a single frame of Downton Abbey
c) throwing a cup of dog urine into the Wachusett reservoir
d) Lead levels in water samples in 2/3 of the 400 plus homes tested by the MWRA
Note no higher math than 3rd grade is needed for the above