Ask Greenlaurel: We have great Baltimore City tap water. Do I still need to filter our tap water?
Short answer: Yes. Tap water needs to be filtered to remove unintended and unavoidable chlorine by-products and contaminants. Greenlaurel suggests installing an under-the-sink Big Blue filter for the cold water line.
Here's why and what to do:
For the most part, our drinking water is clean because in 1973 the Safe Water Drinking Act was signed into law and set minimum health standards for municipal-supplied tap water.
Here in Charm City, the Baltimore City Department of Public Works supplies 2 million homes with drinking water. Baltimore is known for good water that meets all federal standards and ranks in the top 20 for water quality and taste.
Baltimore's (and all cities) tap water “catch-22”
Even though Baltimore enjoys good water, there’s a catch-22 because our water is disinfected with chlorine. Tap water needs to be filtered to remove unintended and unavoidable chlorine by-products and contaminants. Filtering drinking water is a homeowner’s responsibility to ensuring clean and healthy drinking water and may help you and your family avoid health issues in the future.
Unintended consequences - chlorine by-products
Since the 1920s, chlorine has been used by most water treatment plants to disinfect water; it’s cheap and effective and saves millions of lives. Until 1915, when Baltimore began disinfecting water with chlorine, roughly 2,000 Baltimoreans died each year (4% of the population) from water-borne illnesses.
To ensure that your home’s water stays contaminant-free between the water treatment plant and your tap, drinking water leaves the treatment plant chlorinated at 1 ppm (part per million). But, as the water travels through Baltimore City pipes to your tap, the chlorinated water reacts with organic matter (rust, dirt, leaves) and unavoidably forms chlorine by-products.
Discovered in 1979, the 600 or so chemicals that make up chlorine by-products are grouped into THMs (trihalomethane s) and HAAs (haloacetic acids). The 2011 Baltimore Water Quality report reveals that Baltimore meets all regulatory requirements for chlorine by-products and other contaminants with levels hovering right at the legal limits.
Chlorine by-products linked to increased bladder cancer.
Substantial scientific research reveals that THMs are linked to higher bladder and rectal cancer rates in people. The Environmental Protection Agency (EPA) began regulating chlorine by-products in 1998 and created maximum allowable levels for THMs (80 ppb) and HAAs (60 ppb). Chlorine by-products are classified by the EPA as a “Group B” carcinogen, a probable carcinogen based on lab research on animals. Estimates are that 20 percent of bladder and rectal cancers are due to chlorine by-products.
Filtering you tap water
The good news is that homeowners have control and can easily filter their drinking water to eliminate chlorine by-products and contaminants for healthier and better-tasting water with a charcoal-based filter. Click here for a water filter chart and best picks.
Greenlaurel has tried them all, and in the end, an under-the-sink unit installed by a plumber for $200 is the most convenient. The Pentak's "Big Blue" under sink filter is switched out every 6 months.