Annual Drinking Water Quality Report
July 1, 2007

Download the Water Quality Report in PDF  |  Monitoring Violations Under the Safe Drinking Water Act

The City of Rockville is pleased to present the 2006 Annual Drinking Water Quality Report. This report is designed to inform you about the quality of City water and opportunities you have to participate in important community drinking water decisions. Rockville provides water to approximately 50,000 people that live or work in the City. Another 10,000 Rockville residents get their water from the Washington Suburban Sanitary District (WSSC). WSSC will be issuing a separate consumer report for residents on their system.

Rockville’s goal is to always provide the City residents and businesses we serve with a safe and dependable supply of water. During 2006, Rockville water met all of the drinking water health standards established by the U.S. Environmental Protection Agency and the Maryland Department of the Environment. Rockville will continue to meet this obligation in the face of significant population and job growth expected by the City. In fact, our ability to provide an ample supply of clean water is one of the many reasons why Rockville attracts new people and companies to the City.

Spanish (Español)
Este informe contiene informacion muy importante sobre la calidad de su agua beber. Para mas información sobre la calidad de agua que usted consume, llame (240) 314-8500.

Is my water safe?
Yes, Rockville water is very safe. This report is a snapshot of the city’s drinking water quality during 2006. Included in this report are details about where your water comes from, what it contains, and how it compares to standards set by regulatory agencies. In 2006, we tested the water for over 80 different potential contaminants. Many of these tests did not find even a trace amount of the contaminant in the water.

Do I need to take special precautions?
The general population should not be concerned about consuming Rockville’s water. However, some people may be more vulnerable to even small amounts of contaminants in drinking water than others. Immuno-compromised persons such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants can be particularly at risk from infections. These people should seek advice about drinking water from any source from their health care providers. EPA/Centers for Disease Control (CDC) guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available by calling the Safe Water Drinking Hotline (800-426-4791).

Where does my water come from?
Our primary source of water is the Potomac River. When the City water plant is not operating because of necessary improvements or maintenance activities, or in cases of regional drought, Rockville purchases water from the Washington Suburban Sanitation Commission (WSSC). In 2006, Rockville purchased over 85 million gallons of water (about 4.7%) from WSSC, which also gets its water from the Potomac.

Source water assessment and its availability
The Maryland Department of the Environment (MDE) performed a source water assessment several years ago. Copies of this assessment may be obtained by contacting the Water Supply Program at MDE located at 1800 Washington Blvd, Baltimore, Maryland 21230, (410) 537-3702. For more information on the Maryland Source Water Protection Program see
www.mde.state.md.us/Programs/WaterPrograms/Water_Supply/sourcewaterassessment/index.asp

Why are there contaminants in my drinking water?
Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that water poses a health risk. More information about contaminants and potential health effects can be obtained by calling the Environmental Protection Agency’s (EPA) Safe Drinking Water Hotline (800-426-4791). The sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs, and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals and, in some cases, radioactive material, and can pick up substances resulting from the presence of animals or from human activity:

Microbial contaminants, such as viruses and bacteria, come from sewage treatment plants, septic systems, agricultural livestock operations, and wildlife;

Inorganic contaminants, such as salts and metals, can be naturally occurring or result from urban stormwater runoff, industrial, or domestic wastewater discharges, oil and gas production, mining, or farming;

Pesticides and herbicides come from a variety of sources such as agriculture, urban stormwater runoff, and residential uses;

Organic chemical contaminants, including synthetic and volatile organic chemicals, are by-products of industrial processes and petroleum production, and can also come from gas stations, urban stormwater runoff, and septic systems; and

Radioactive contaminants can be naturally occurring or be the result of oil and gas production and mining activities.

In order to ensure that tap water is safe to drink, EPA prescribes regulations that limit the amount of certain contaminants in water provided by public water systems. Food and Drug Administration (FDA) regulations establish limits for contaminants in bottled water that must provide the same protection for public health.

Water Quality Data Table

The table below lists all of the drinking water contaminants that we detected during the calendar year of this report. The presence of contaminants in the water does not necessarily indicate that the water poses a health risk. Unless otherwise noted, the data presented in this table is from testing done in the calendar year of the report. The EPA or the State requires us to monitor for certain contaminants less than once per year because the concentrations of these contaminants do not change frequently.

Reported levels are maximum values unless indicated otherwise.
Disinfectants & Disinfection By-Products.
(There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.)

Undetected Contaminants

The following contaminants were monitored for, but not detected, in your water.