November 29, 2013 (BALTIMORE, MD) — Public Works Director Alfred H. Foxx today announced that due to a violation for one byproduct of the drinking water filtration process, the Department of Public Works (DPW) will send a legally required notice to customers who may have used the water. Although this incident was not an emergency, our customers have the right to know what happened and what we are doing to correct the situation.

DPW routinely monitors dozens of sampling stations across our distribution area for the presence of drinking water contaminants. Quarterly sampling from October 2012 to September 2013 showed an average value for haloacetic acids (HAA5) at the Lutherville sampling location that exceeded the maximum permitted level by 2 parts per billion. The maximum allowable level for HAA5 is 60 parts per billion; this location indicated a value of 62 parts per billion. The annual averages for all other sampling locations were below the maximum allowable level.

This is not an emergency. Customers do not need to boil their water or take other corrective actions. If it had been an emergency, the affected customers would have been notified immediately.

Haloacetic acids form when disinfectants used in the water purification process react with natural organic matter in water. People who drink water containing HAA5 in excess of the maximum contaminant level (MCL) over many years may have an increased risk of getting cancer.

In recent years the allowable level for HAA5 has become more stringent, and sampling locations are now based on those with the historically highest levels. DPW performs monthly sampling for HAA5, three times as often as the mandatory quarterly sampling. If the monthly values were used to calculate the annual average, the result would have been 56 parts per billion, well within permitted levels.

Certain people may be at an increased risk. Customers with severely compromised immune systems, infants, pregnant women, and the elderly are at an increased risk, and may wish to seek advice from their health care providers.
Baltimore City has a very old water system which includes large finished drinking water reservoirs and old water pipes. HAA5 values for water leaving our three water treatment plants are relatively low, but the size and age of the distribution system contributes to higher levels in some isolated areas.

DPW has a number of plans in place to help reduce HAA5, including covering finished water reservoirs, increased mixing of water at its storage tanks, and replacing older distribution pipes. Some of these efforts are already being enacted, while others will require several years to complete.

Our most recent sample value for HAA5 was below the maximum permitted level.