Pittsburgh, Pennsylvania

In Pittsburgh, I sample water from two different faucets on one sink: the first is normal tap water and the second comes from a reverse osmosis filter beneath the sink.  

The normal tap has a strong odor of chlorine disguising the scent of something slightly sour. When sipped, it is full and thick. Chalky melon is the dominating flavor. It is vicious to swallow, but leaves a fresh after taste. 

Then, on the side of the sink where in-counter soap dispensers sometimes are, there is a small spigot that pulls water from the reverse osmosis reservoir underneath the counter. This water comes out with force in a clear, round stream. It is almost like that waterjet dental tool, but with a much thicker steam. The water is entirely odorless. This version is soft in the mouth and bland in flavor. 

Can I tell the difference without drinking them back to back? No. 

So, why have two sources of drinking water? The answer is lead.

Lead in the Water

Pittsburgh sources its water from the Allegheny River, but that is not the problem. 

In 2016, the city of Pittsburgh began to detect high levels of lead in its drinking water. Based on the federal Lead and Copper Rule, any concentration of lead above 15 ppb (parts per billion) in at least 10% of customer taps sampled requires that the water managing authority take a series of actions to address corrosion in pipes. 

Upon exceeding the federal limit, Pittsburgh Water and Sewer Authority (PWSA) underwent an evaluation of corrosion in their water infrastructure. They began to replace water lines in 2017. 

Unfortunately, the municipal water authorities in Allegheny County did not have permission to use funding to replace service pipes that brought water onto private property. In many cases, replacing lead lines in the street actually led to a temporary spike in lead levels because corrosion on the private lines was disturbed. 

The private dilemma has since been addressed. PWSA and other water authorities now have extended permissions to use public funding to replace all lead lines. The work, though, is not complete. A lawsuit from some civil society groups now dictates that the replacement must be complete by 2026. 

In the meantime, lead levels have dropped below the 15 ppb that triggers EPA action, but there is still lead in the water–and no level of lead is technically safe. Advocacy efforts point to the inequitable access to clean drinking water in the city. At the same time, elevated blood lead levels (EBLLs) among children under the age of six exist in pockets around Allegheny County. 

Which brings us to the reverse osmosis filter. 

How Does Reverse Osmosis Work?

Osmosis is a middle school science topic. It is the inactive transport of liquids across a membrane. When one side of a semipermeable membrane has a higher concentration of something, solvent particles on either side will move across the membrane until an equilibrium is reached. 

This liquid membrane idea is the basis of reverse osmosis. In the case of water filters, reverse osmosis takes water with impurities in it and uses energy to force it through a membrane that has holes in it big enough only for individual water molecules. That water may also pass through charcoal filters to take larger contaminants out or remove unpleasant flavors.

These filters are highly effective at removing toxins from water, so many households in Pittsburgh have decided to buy them in order to avoid any danger that municipal water may pose. 

I drank both tap and reverse osmosis. A little sip of Pittsburgh water won’t hurt me, but chronic consumption of lead in children is highly dangerous.